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Home My WebLink AboutSWP272267(3) AG RA Earth & Environmental 1 ' GEOTECHNICAL ENGINEERING REPORT KENNYDALE SEWER INTERCEPTOR AND STORM DRAIN ALTERNATIVES 1 AND 1A RENTON, WASHINGTON Submitted to: 1 R. W. Beck, Inc. 1 2101 Fourth Avenue, Suite 600 Seattle, Washington 98121-2375 t Submitted by: 1 1 AGRA Earth & Environmental, Inc. 11335 NE 122nd Way, Suite 100 Kirkland, Washington 98034-6918 i i ' January 1997 1 6-91 M-10292-B ' 6-91 7-10292-B.108 1 , AG R A Earth & Environmental 1 1 , AGRA AGRA Earth & Earth & Environmental 11335 NE 122nd way ' Suite 100 Kirkland, Washington U.S.A. 98034-6918 8 January 1997 Tel (206) 820-4669 6-917-10292-B Fax(206) 821-3914 ' R.W. Beck, Inc. 2101 Fourth Avenue, Suite 600 Seattle, Washington 98121-2375 tAttention: Mr. Mike Giseburt ' Subject: Subsurface Exploration and Geotechnical Engineering Report Proposed Kennydale Sewer Interceptor and Storm Drain, Alternatives 1 and 1 A Aberdeen Avenue and NE 24th Street Renton, Washington Dear Mr. Giseburt: ' This report presents the results of our subsurface exploration and geotechnical engineering evaluation for the above referenced project. This scope of work was performed in accordance ' with our proposal letter dated 31 January 1996. Our work for Alignment 1 A was authorized by you via an R.W. Beck, Inc. contract amendment dated February 16,1996, and our geotechnical observations and recommendations for Alignment 1 A were published in draft form ' in our report dated 19 April 1996. Our work for the Alignment 1 project phase was authorized by a letter from R.W. Beck, Inc. dated 15 October 1996, instructing us to proceed with the Alignment 1 work phase described in our original proposal dated 31 January 1996. This report ' has been prepared in accordance with accepted geotechnical engineering practices for the exclusive use of R. W. Beck, Inc., the City of Renton, and their agents for specific application ' to this project. We recommend that we be allowed to review completed project plans and specifications, in accordance with our agreement, to ensure that our recommendations have been adequately interpreted and incorporated into project design documents. ' We appreciate the opportunity to be of service on this project. If you have any questions or desire further information, please do not hesitate to call. Respectfully submitted, ' AGRA Earth & Environmental, Inc. ' Bruce W. Guenzler Project Geologist Engineering& Environmental Services ' 6-917-1 o292-B.1 08 ' TABLE OF CONTENTS 6-91 M-10292-B 1 .0 SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 ' 2.0 PROJECT DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1 Alignment 1 A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 ' 2.2 Alignment 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3.0 EXPLORATORY METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 ' 4.0 SITE CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.1 Development Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4.1.1 Alignment 1A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 ' 4.1.1 Alignment 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.2 Surface Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.3 Project Area Geology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 ' 4.4 Soil Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 4.5 Laboratory Testing 11 4.6 Groundwater Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 ' 5.0 CONCLUSIONS AND RECOMMENDATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 5.1 Site Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 ' 5.2 Structural Fill . . . . : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 13 5.3 Temporary Slopes 15 5.4 Dewatering Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 ' 5.5 Excavation Shoring . . . . : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 18 5.5.1 Slip Box Shoring 18 5.5.2 Sheet Pile Shoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 ' 5.6 Shoring Monitoring : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 19 5.7 Microtunneling 20 5.8 Construction Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 ' 6.0 CLOSURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Figure 1 — Location Map ' Figure 2 — Site & Exploration Plan Figure 3 Surcharge Pressures Acting on Adjacent Shoring or Subsurface Walls ' Appendix A — Field Exploration Procedures and Logs Appendix B — Laboratory Testing Procedures and Results ' Boring Logs B-1 through B-11 Test Pit Logs TP-1 and TP-2 ' Hand Auger Boring Log HB-1 Grain Size Distribution Graphs 6-917-10292-B.10B ' GEOTECHNICAL ENGINEERING REPORT 6-91M-10292-B KENNYDALE SEWER INTERCEPTOR AND STORM DRAIN ALTERNATIVES 1 AND 1A RENTON, WASHINGTON 1.0 SUMMARY ' • The project appears feasible from a geotechnical standpoint with respect to the subsurface conditions observed in our explorations. Consideration will be required during construction for temporary cut slope inclinations, temporary ' excavation shoring, and temporary excavation dewatering. • Project Description: The proposed project would construct new sections of ' storm drain and sanitary sewer in the Kennydale Hill area of Renton, Washington. The new utilities would be constructed together in one of two possible alignments. Both alignments begin near an existing pump station near the intersection of Aberdeen Avenue Northeast and Northeast 24th Street, and end in connections to existing utilities on Northeast 27th Street but follow different ' routes. Each alignment is approximately 1,500 feet in length. Alignment 1, the preferred alternative at this time, would be an open - cut construction project with the two utilities located within the same excavation. Alignment 1 A would ' be constructed by microtunneling in locations where the depth of the pipes exceeds 25 feet, and by open - cut methods where depths are less than 25 feet. Attached with this report is a Site and Exploration Plan (Figure 2) that shows the different alignments, as well as the approximate locations of explorations completed for this study. ' • Exploratory Methods: We explored subsurface conditions by means of nine hollow stem auger soil borings, two HiWay auger soil borings, two backhoe test pits, and one hand auger boring, advanced at strategic locations along the two ' possible alignments. Exploration depths ranged from about 3 to 57 feet below existing grades. Our explorations were completed in two phases, one during March and April 1996, and one during November 1996. Logs of our explorations ' are appended to this report. • Soil Conditions, Alignment 1 A: The subsurface conditions observed in our ' explorations along the Alignment 1 A route generally consisted of medium dense to very dense silty gravelly sand, mantled by loose to medium dense gravelly sand with trace to some silt, along with less extensive layers of hard silt. • HiWay Auger Borings-Alignment 1A: Each of the two HiWay auger borings was terminated due to caving soil conditions at relatively shallow depths. Temporary excavation support will be required for excavation side slopes steeper than 1 .51-1:1 V above the groundwater level. 6-917-10292-B.1 08 ' R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 3 ' • Groundwater Conditions. Alignment 1 A: Groundwater was observed in five of the six hollow-stem auger borings on Alignment 1 A at varying depths, as noted on the boring logs. Most of the planned microtunneling and open cuts penetrate below observed groundwater levels. Dewatering is recommended in advance of open excavations. • Microtunneling Analysis. Alignment 1A: Our analysis indicates that ' microtunneling would be generally feasible with respect to subsurface conditions encountered on the site. Microtunneling operations would likely require shored and dewatered excavations for the staging areas. Microtunneling subcontractors ' should be made aware of the dense soil conditions, potential for encountering larger rocks during drilling, and potentially high groundwater conditions, all of which could contribute significant difficulty to the project. ' • Soil Conditions, Alignment 1: Portions of Alignment 1 are nearly coincident with portions of Alignment 1A, and the explorations advanced during our investigation of Alignment 1 A were used to develop our recommendations for Alignment 1 in those areas. Those explorations located on Alignment 1 generally encountered thick layers of loose to medium dense sand with trace silt and varying gravel ' content. In one of the three borings on Alignment 1, and two of the borings located on both Alignment 1 A and Alignment 1 these surficial soils were underlain by dense silty soils. ' • Test Pits-Alignment 1 : Test pit TP-1 encountered some fill material and severe caving, and test pit TP-2 encountered moderate caving during excavation. ' Temporary excavation support will be required for excavation side slopes steeper than 1.5H:1 V above the groundwater level. ' • Groundwater Conditions. Alignment 1: Groundwater was observed in five of six borings completed on Alignment 1 at varying depths, as noted on the boring ' logs. It appears that much of Alignment 1 will require utility construction below observed groundwater levels. Dewatering is recommended to facilitate construction. • Slope Recommendations-Both Alignments: Most of the shallow soils observed in our explorations were relatively granular and loose, while more dense and well graded soils were generally encountered below the granular deposits. For typical temporary unshored excavations in the upper granular soils, side slopes of 1.5H:1 V (Horizontal:Vertical) are recommended where worker access is ' necessary. Temporary slope design should also consider any surcharges or adjacent settlement-sensitive structures, as discussed in the text of this report. All temporary excavations should be made in accordance with applicable safety regulations. 6-1117-102112-8.1011 ' R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 4 ' • Shoring Recommendations-Both Alignments: Where construction easement widths, locations of adjacent structures, adjacent surcharges, or other factors ' limit the width of open excavations, some form of temporary excavation shoring should be used. Recommended methods of temporary shoring are utility trench slip boxes and braced sheet pile shoring. Slip box shoring has the advantage of lower cost, but with the potential to disturb a relatively wider area during construction. Slip box shoring should only be used where groundwater levels ' have been lowered to at least two feet below the base of the excavation, and where disturbance within an area defined by a line projected upwards and outwards from the excavation base at an angle of 0.75H:1 V to 1 H:1 V can be ' tolerated. Sheet pile shoring should be used where surcharges or settlement sensitive structures are located within an area defined by a line projected upwards and outwards from the excavation base at an angle of 1 H:1 V. ' • Dewatering Recommendations-Both Alignments: Open excavations should be facilitated by dewatering sufficient to lower the groundwater level at least two ' feet below the excavation base. Dewatering for excavations that penetrate less than 4 feet below groundwater levels should use pumped sumps within the excavation for dewatering, while excavations that must penetrate deeper than ' 4 feet below static groundwater levels should be preceded by dewatering with pumped wells. We anticipate that some temporary dewatering will be required for either alignment. • On-site Soil Considerations: At the time of our exploration programs, all of the soil samples recovered from below groundwater levels contained moisture levels ' above those considered optimum for compaction purposes. Soil samples recovered from above static groundwater levels were typically near or slightly ' above optimum moisture content. We anticipate that a large percentage of the excavated soils will not be compactible to a firm and unyielding condition without drying, although compaction to 90 percent of the modified Proctor ' maximum density might be possible with less silty soils. We therefore recommend planning for use of imported granular backfill material for the upper 4 feet of backfill soils beneath roadways or other structures, and to full depth in any areas where the backfill is within the bearing splay of existing or planned foundations, embankments, or other structures. Alternatively, site soils could be used for backfill in these areas if their moisture content can be lowered by aeration or drying during dry warm weather to within one to two percent of optimum. Imported soil materials should be anticipated for pipe bedding in open excavations. This summary is presented for introductory purposes only, and should be used in conjunction with the full text of this report. The site location is indicated on the Location Map, Figure 1, 1 and the site and approximate locations of explorations accomplished for this study are 15-917-10292-B.108 ' R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 5 ' presented on the Site and Exploration Plan, Figure 2. Exploration procedures and logs for subsurface explorations completed for this study, along with laboratory test results and an 1 explanation of the soil description methodology used in this report, are appended to this report. 2.0 PROJECT DESCRIPTION ' The proposed project would construct new sections of storm drain and sanitary sewer in the Kennydale Hill area of Renton, Washington. The new utilities would be constructed together ' in one of two possible alignments. Both alignments begin near an existing pump station near the intersection of Aberdeen Avenue Northeast and Northeast 24th Street, and end in connections to existing utilities on Northeast 27th Street. Each alignment is approximately ' 1 ,500 feet in length, and each has a different project stationing system. Alignment 1, the preferred alternative at this time, would be an open - cut construction project with the two utilities located within the same excavation. Alignment 1A would be constructed by microtunneling in locations where the depth of the pipes exceeds 25 feet, and by open - cut methods where depths are less than 25 feet. The alignments begin and end at the same locations, but follow different routes. Attached with this report is a Site and Exploration Plan ' (Figure 2) that shows the different alignments, as well as the approximate locations of explorations completed for this study. ' It should be emphasized that the conclusions and recommendations contained in this report are based on our understanding of the currently proposed utilization of the project site, as derived from preliminary drawings, written information, and verbal information supplied to us. Consequently, if any changes are made in the currently proposed project, we may need to modify our conclusions and recommendations contained herein to reflect those changes. After specific locations and project details have been established, AEE should be allowed to review project plans and specifications to ensure that our geotechnical recommendations have been adequately interpreted and incorporated into the project documents. Review of the completed project documents was included in our scope and cost proposal. 2.1 Alignment 1A ' Alignment 1A is located along Aberdeen Avenue Northeast and Northeast 27th Street. The project begins at the south end of Kennydale Lions Park, at approximately project station 1 + 100 (meters), continues northward through the park, crosses to the west side of Northeast 24th Street at the north end of the park, continues northward along 24th to the intersection with Northeast 27th Street, and then proceeds westward along 27th to the end of the section at approximately project station 1 +600 (meters). The alignment section considered in this study is approximately 1,500 feet in length. We understand that although other options were considered, the chosen location for Alignment 1A through Kennydale Lions Park is the one that crosses near the center of the park, rather than on the west side at the base of the roadway embankment. The project location is indicated on the Location Map, Figure 1, and the alignment location, along with approximate locations of the explorations completed for this study are indicated on the Site and Exploration Plan, Figure 2. 6-9 17-10292-B.106 ' R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 6 Most of Alignment 1A is currently characterized by asphalt paving along Northeast 27th Street and Aberdeen Avenue northeast, or by landscaping in Kennydale Lions Park. Topography along ' the alignment achieves its highest point at the intersection of Aberdeen Avenue Northeast and Northeast 27th Street, and slopes down moderately to steeply to the south and west. ' The proposed project alternative 1 A would include construction of a new sanitary sewer line along the alignment. A new storm sewer line would be constructed concurrently in the same excavation or tunnel as the sanitary sewer line. Due to gradient constraints, it will be necessary to construct the new sanitary sewer with invert elevations up to approximately 52.5 feet below the existing ground surface. Portions of the alignment where the planned invert elevation is ' less than approximately 25 feet deep will be constructed by conventional open cut techniques. Alignment sections that would require excavation exceeding 25 feet deep would be constructed in small diameter (60 inch or less) tunnels. ' 2.2 Alignment 1 Alignment 1 begins at generally the same location and is essentially coincident with Alignment 1A to the north end of Kennydale Lions Park. At the north end of the park, at approximately Alignment 1 project station 1 +400 (meters), Alignment 1 turns west and proceeds down an existing gravel driveway approximately 500 feet. At the west end of the driveway, the alignment enters an undeveloped area, and proceeds through woods , pasture land, and a wetland area to the end of the project on NE 27th Street. The new sewer and storm drain would pass near a home and garage near the end of the Alignment on NE 27th Street. Alignment 1 is currently characterized by Kennydale Lions Park, a gravel driveway, undeveloped woods and pasture, and a residential homesite at the west end of the alignment. The highest ' topographic point on the alignment is located in Kennydale Lions Park, and slopes along the alignment vary from gentle to moderately steep. ' 3.0 EXPLORATORY METHODS Subsurface conditions were observed in nine hollow stem auger soil borings, two HiWay auger ' borings, two backhoe test pits, and one hand auger boring. The hollow stem auger and HiWay auger borings were completed in March, April, and November 1996 by local drilling companies under subcontract to AGRA Earth & Environmental, Inc. (AEE). The test pits were excavated during preparation of drill rig access trails, using a track-mounted excavator operated by a local excavating contractor. The hand auger boring was advanced in an area inaccessible to other equipment by using a T-handled soil auger. The approximate exploration locations are indicated on the attached Site and Exploration Plan, Figure 2. Exploration procedures and logs are included at the end of this report. ' We explored surface and subsurface conditions at the project site in two phases: Alignment 1 A explorations were completed during March and April 1996, while Alignment 1 explorations were completed during November 1996. Our exploration and testing program comprised the following elements: 6.917.10292-B.108 1 1 R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 7 ' • A visual surface reconnaissance of the site; ' • Nine hollow-stem auger soil borings (designated B-1 through B-6 and B-9 through B-1 1); ' • Two HiWay auger borings (designated B-7 and B-8); • One hand boring (designated HB-1) advanced at a location inaccessible to powered equipment; • Two test pits (designated TP-1 and TP-2); • Three groundwater observation wells installed in three of our borings (B-2, B-5, and B-10); • Thirteen grain size analyses performed on selected soil samples obtained from ' beneath the alignments; • A review of published geologic maps . 1 Table 1, below, summarizes the approximate locations, surface elevations, and termination depths of our subsurface explorations, and Figure 2 depicts their approximate locations. ' Appendix A of this report describes our field exploration procedures, and Appendix B describes our soil classification and laboratory testing procedures. The specific number, locations, and depths of our explorations were selected in relation to the existing and proposed site features, under the constraints of surface access, underground utility conflicts, and budget considerations. We estimated the relative location of each exploration ' by measuring from existing features and scaling these measurements onto a layout plan supplied to us, then we estimated their elevations by referencing project profiles and 1 topographic information, where it was available. Consequently, the data listed in Table 1, the elevations listed on the exploration logs, and the locations depicted on Figure 2 should be considered accurate only to the degree permitted by our data sources and implied by our ' measuring methods. i 1 1 6-917-10292-a.10e 1 R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 8 TABLE 1 APPROXIMATE LOCATIONS, ELEVATIONS, AND DEPTHS OF EXPLORATIONS Exploration Functional Location Surface Termination ' Elevation Depth (feet) (feet) B-1 South side of Kennydale Lions Park 282 35 ' B-2 Kennydale Lions Park Parking Lot 285 33 B-3 Aberdeen Avenue NE 278 31 B-4 Intersection of Aberdeen and NE 27th 301 57 1 B-5 NE 27th Street 270 34 B-6 NE 27th Street 243 14 B-7 Vacant Lot (HiWay Boring) 243 14 B-8 Kennydale Lions Park (HiWay Boring) 285 14 B-9 Pasture Area 255 24 B-10 Pasture Area 262 36Y2 B-11 Gravel Driveway 275 21 TP-1 Wooded Area 265 16 ' TP-2 Wooded Area 265 10 HB-1 Boggy Area 1 243 1 3 Elevation datum: Site Profiles by R.W. Beck, Inc. It should be emphasized that the explorations performed for this evaluation reveal subsurface conditions only at discrete locations along the project alignments and that actual conditions could vary between these exploration locations. Furthermore, the nature and extent of any such variations would not become evident until additional explorations are performed or until construction activities have begun. If significant variations are observed at that time, we may need to modify our conclusions and recommendations contained in this report to reflect the ' actual site conditions. 4.0 SITE CONDITIONS ' The following sections of text present our observations, measurements, findings, and interpretations regarding site development, surface, soil, and groundwater conditions at the project site. Descriptive logs of our subsurface explorations and graphic results of our laboratory tests are included in Appendix A and Appendix B, respectively, of this report. 4_1 Development Conditions From the beginning of the alignments near Aberdeen Avenue NE and NE 24th Street, the two routes follow similar paths under NE 24th Street and through Kennydale Lions Park. Development conditions along the two alignments are significantly different west of Kennydale 6-9 T7-10292-B.108 ' R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 9 ' Lions Park. Alignment 1A is generally more developed, and in close proximity to more sensitive structures than Alignment 1. 4.1.1 Alignment 1A West of Kennydale Lions Park, Alignment 1 A would be located beneath Aberdeen Avenue NE ' to the intersection with NE 27th Street, and then turn west beneath NE 27th Street to the junction with existing utilities. Virtually all of Alignment 1 A west of Kennydale Lions Park is ' located beneath existing roadways. 4.1.1 Alignment 1 1 West of Kennydale Lions Park, Alignment 1 follows an existing gravel driveway for approximately 500 feet, then enters an area of woods, pasture, and wetland area. The alignment is located adjacent to a house and garage near the west end at the junction with 1 existing utilities. With the exception of the area beneath the gravel driveway and adjacent to the existing home and garage, the remainder of Alignment 1 A west of Kennydale Lions Park is generally undeveloped or lightly developed with no sensitive structures nearby. 4 2 Surface Conditions Surface conditions along the two alignments are significantly different. Alignment 1A is located ' primarily along developed right of way and in Kennydale Lions Park. Alignment 1 is located primarily in Kennydale Lions Park, along a gravel driveway, and on undeveloped land. 4-3 Project Area Geology We researched the project area geology in the United States Department of Agriculture Soil Conservation Service Soil Survey for King County, Washington, and in the Preliminary Geologic ' Map of Seattle and Vicinity, Washington, by Waldron, Liesch, Mullineaux, and Crandell. Based on the published geologic information the project area is generally characterized by glacially derived granular sand and gravel soils at the ground surface. 4_4 Soil Conditions ' Subsurface conditions observed in our borings generally consisted of loose to dense sand with some gravel and trace to some silt. Borings B-1 through B-5 and B-1 1 encountered interlayered silty sand and silt within deeper portions of those borings. The soil conditions were generally ' somewhat variable, and changes in soil density and gradation with depth and map locations were typical of the soil conditions in our borings. Most of the hollow stem auger soil borings penetrated below static groundwater levels. Because of the granular nature of the site soils, 1 soil "heave" was encountered during drilling below the groundwater interface. Heave occurs when groundwater enters the borings and\or the auger, carrying with it entrained particles of the subsurface soils. The HiWay auger borings encountered substantial heave and caving at relatively shallow depths. The depth of completion of the HiWay auger borings was limited by heaving soil and caving in both borings. 6-917-10292-B.108 R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 10 The two test pits completed for this study encountered similar soil conditions to those observed in the borings. Loose sandy soils were observed in the test pits, and severe caving of the test ' pit sidewalls was observed in TP-1 . Hand auger boring HB-1 was completed in a low-lying wet area inaccessible to other equipment. ' The depth of HB-1 was limited by shallow groundwater; however, the soil conditions observed in HB-1 included an organic topsoil horizon above saturated sand similar in gradation to soils observed in other explorations. Table 2, below, summarizes the approximate thicknesses, depths, and elevations of soil 1 deposits encountered in our subsurface explorations. TABLE 2 ' APPROXIMATE THICKNESSES, DEPTHS, AND ELEVATIONS OF SOIL LAYERS ENCOUNTERED IN EXPLORATIONS Exploration Thickness of Thickness Thickness of Thickness of Elevation of Topsoil of Paving Loose to Dense to Dense to (feet) and Gravel Medium Very Dense Very Dense Base Dense Sand Sand and Soils (feet) (feet) Silty Sand (feet) (feet) B-1 N/E '/2 10%2 24 271 B-2 '/2 N/E N/E 33 284 B-3 N/E 1 14 17 263 B-4 N/E '/2 30 27 271 B-5 N/E '/2 32 2 238 B-6 N/E '/2 15 N/E N/E B-7 '/2 N/E 14 N/E N/E B-8 N/E '/2 14 N/E N/E B-9 '/2 N/E 24 N/E N/E B-10 '/2 N/E 36 N/E N/E B-1 1 '/2 N/E 17 4 258 TP-1 '/2 N/E 16 N/E N/E TP-2 1 N/E 10 N/E N/E HB-1 1 '/2 N/E 1 '/2 N/E N/E Elevation datum: Site Profiles by R.W. Beck, Inc. N/E = not encountered within depth of exploration 6-917-10292-8.108 ' R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 11 4.5 Laboratory Testing A grain size analysis indicates the range of soil grain sizes included in a particular sample based ' on particle diameter. Grain size analyses were performed on 13 representative samples in general accordance with ASTM:D-422. The results of the grain size determinations are presented at the end of this report. ' Moisture content determinations were performed in conjunction with grain size analyses in order to aid in identification and correlation of soil types. The determinations were made in general ' accordance with the test procedures described in ASTM:D-2216. Moisture contents are included on the grain size reports and on the exploration logs, where appropriate. 4,E Groundwater Conditions Six of nine hollow stem auger borings and one of two HiWay auger borings encountered water ' at depths of 8 to 23 feet below the existing ground surface at the time of drilling. Three of the hollow stem auger borings, B-2, B-5, and B-10 were completed with open standpipe piezometers for monitoring groundwater levels after drilling. Subsequent groundwater ' monitoring is noted on the boring logs included with this report. In general, our groundwater observations indicate that most or all of the pipe planned along the subject portion of Alignments 1 and 1A will be installed below or in close proximity to the static groundwater ' level. Groundwater conditions should be anticipated to vary in response to changes in seasonal precipitation, on and off site land usage, and other factors. 1 5.0 CONCLUSIONS AND RECOMMENDATIONS The proposed project appears feasible from a geotechnical standpoint with respect to the subsurface conditions observed in our explorations. Completion of conventional cut - and - 1 cover pipe installations will require sloped excavations, excavation shoring, and dewatering. Pipe sections constructed in microtunnels will require excavation shoring and dewatering in tunneling staging areas, and may require temporary dewatering in the tunneling zones. ' The following text sections of this report present our specific geotechnical conclusions and ' recommendations regarding site preparation, structural fill, temporary slopes, dewatering, shoring, shoring monitoring, microtunneling, and construction monitoring. WSDOT Standard Specifications cited herein refer to WSDOT publications M41-10, 1994 Standard Specifications for Road, Bridge, and Municipal Construction. ,L1 Site Preparation The silty soils which will be encountered in some areas on the site are highly prone to disturbance when wet. To reduce site disturbance, the contractor should minimize traffic above any prepared subgrade areas. During wet site conditions, the use of geotextile reinforcement ' fabrics and a working surface of quarry spalls or sand and gravel may be required to protect subgrades, especially from vehicular traffic. Earthwork during wet site conditions may result in disturbance of the site soils and may require imported backfill or soil drying and recompaction ' to repair the disturbed areas. If earthwork takes place during freezing conditions, we 6-917.10292-B.1 06 1 ' R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 12 ' recommend that the exposed subgrade be allowed to thaw and be recompacted prior to placing subsequent lifts of structural fill or foundations for any permanent structure. Preparation of the ' project site should involve temporary drainage, clearing, stripping, and relocation of conflicting utilities. The paragraphs below discuss our geotechnical comments and recommendations concerning site preparation. Prior to site grading, any site surface runoff and groundwater seepage should be collected and routed away to a proper drainage to facilitate earthwork construction. Once surface runoff and groundwater seepage are controlled, all areas of the site to be excavated should be stripped of all topsoil, vegetation, and existing paving, and the deleterious surficial material segregated ' from native soil materials if they are suitable for reuse when excavated. We estimate that stripping depths will vary from approximately 6 inches to one foot below existing grades. Any existing buried utilities on the site should be removed, relocated, abandoned, or worked around as necessary. All utility work should be performed in accordance with applicable Federal, State, and City regulations. Localized excavations below finished grades made for removal of utilities should be backfilled with structural fill as outlined in the following section of this report. ' Excavations extending down into very dense native soils may be difficult to construct due to the nature of the material. The contractor should be prepared to use large excavating machinery equipped with ripper teeth, or other suitable means to advance excavations which ' penetrate soils described in our exploration logs as very dense. The following table summarizes where very dense soil conditions are expected: Table 3 1 Summary of Locations of Very Dense Soil Conditions Observed in Subsurface Explorations Exploration Number Very Dense Soils Encountered Below (Depth in Feet) B-1 19 B-2 18 B-3 15 ' B-4 30 B-5 32 B-11 17 Note: Explorations not listed did not encounter very dense soils. 6-911-10292-6.109 ' R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 13 1 Most or all of the deeper excavations for the project will encounter groundwater, and raveling soil conditions that will require adequate sloping or shoring to prevent loss of ground. We ' recommend that shoring and dewatering plans and equipment be in place before beginning any excavations for which shoring or dewatering may be required. 5-2 Structural Fill All structural fill placed in excavations, placed below new pipes for pipe bedding, comprising ' fill slopes or placed where future support of permanent structures of any kind is anticipated should be placed in accordance with the recommendations herein for structural fill. Prior to the placement of structural fill, all surfaces to receive fill should be prepared as previously ' recommended. Structural fill should not be placed into standing water. If proper excavation dewatering is not feasible, we should be contacted to provide situation-specific recommendations for underwater fill placement. 1 Structural fill should be placed in lifts not exceeding 8 inches in loose thickness if compacted with conventional drum rollers or hand operated equipment. Fill placed in confined excavations ' and compacted with vibratory "hoe packs" may be placed in loose lifts of up to 12 inches in thickness when depths below finished grade exceed 4 feet. For the first lift of backfill above new pipes, a single lift of 24 inches may be used to protect the pipe from damage caused by ' heavy compaction equipment. Closer than 4 feet to finish grade, all fill should be placed in 8-inch-thick loose lifts, regardless of compaction method. Individual lifts should be compacted such that a density of at least 90 percent of the modified Proctor maximum dry density ' (ASTM:D-1557) is achieved. The upper 4 feet below paved roads should be compacted to at least 95 percent of the same density standard. If buried pipes with crown elevations shallower than about 6 Y2 feet below road subgrades are planned, some form of ductile iron sleeve or 1 other structural reinforcing may be warranted to protect the pipe during backfilling and road subgrade preparation. We recommend that a representative from our firm be present during the placement of structural fill to observe the work and perform a representative number of in ' place density tests. In this way, the adequacy of earthwork may be evaluated as grading progresses. Although we do not anticipate that soft trench subgrades will be encountered, any ' soft areas should be overexcavated to reveal firm underlying soils. Overexcavations should be backfilled with compacted pipe bedding material. The suitability of soils used for structural fill depends primarily on the gradation and moisture content of the soil when it is placed. As the fines content (that portion passing the U.S. No. 200 Sieve) of a soil increases, it becomes increasingly sensitive to small changes in moisture ' content, and adequate compaction becomes more difficult or impossible to achieve. Soils containing more than about 5 percent fines by weight, such as some of the site soils, cannot be consistently compacted to the recommended degree when the moisture content is more than ' approximately 2 percent above or below optimum. Based on our previous experience with similar soils, we anticipate that the optimum moisture ' content of site soils tested in the laboratory varies from approximately 7 to 10 percent, and 8-81 7-10282-B.108 ' R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 14 ' measured moisture contents of several selected samples ranged from 4 to 27 percent. Most of the tested soils were above their estimated optimum moisture contents. We recommend ' reusing the site soils for excavation backfill when their moisture content can be adjusted to allow compaction to a firm and unyielding condition to the degree required for the situation where they are used. Native soils that are above optimum moisture could also be used even ' if firm and unyielding conditions cannot be attained, provided that a minimum compaction level of 90 percent of the modified Proctor can be maintained, and that no structures are planned ' above the fill. For instance, it may be appropriate to use over optimum soils for backfill in the Kennydale Lions Park area, provided that the trench is located away from the western slope (backfill does not support roadway embankment), that only lawn or landscaping is planned ' above the backfill, and that compaction levels of 90 percent can be achieved. Drying may be accomplished by means of scarifying and windrowing the soils during dry, warm weather conditions, or could be achieved with admixtures such as Portland cement or lime products thoroughly blended into the soils in specific proportions. If site soils are to be reused, we recommend that excavated soils be protected from inclement weather and surface water ' until moisture conditioning and compaction has been completed. If native soils are left unprotected, rain or surface water could render otherwise suitable soils unusable without additional effort to reduce moisture contents. ' If imported soil is required for construction of compacted fills, we recommend that a clean, free draining gravelly sand be used. Import material should contain no particles greater than ' 6 inches in diameter, and should contain less than 5 percent by weight passing the U.S. #200 Sieve, based on that fraction passing the US Number 4 Sieve. All structural fill should be free of organic material, roots, debris, and other deleterious materials. ' Pipe Bedding and Backfill: Sewer lines constructed in open excavations should be supported below the spring line with granular bedding material worked around the pipe by hand. The bedding material should conform to Washington State Department of Transportation (WSDOT) Standard Specifications for Road, Bridge, and Municipal Construction 9-03.15 Bedding Material ' for Rigid Pipe. If the excavated native soils contain gravel larger than approximately 2 inches, the bedding material should also cover the pipe to protect it from damage caused by coarse gravel during compaction. We anticipate that some of the excavated site soils will contain ' coarse gravel. Pipe bedding material should be placed at least 4 inches in thickness below the pipe invert, and 6 inches in thickness above the pipe crown. Backfilling should begin by bedding the pipes up to the spring line, and compacting the bedding at spring line level with hand-operated "jumping jacks" or similar equipment. Bedding material (or native soil of appropriate gradation) should ' then be placed to a depth of 6 inches above the pipe crown, and compacted again with hand- operated equipment. Above the bedding, heavy compaction equipment may be used; however, the first lift of fill above the pipe should provide 2 feet of cover between the equipment and ' pipe. Subsequent lifts of fill should be placed conventionally as described above. These 6-917.10292-B.108 ' R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 15 ' conditions are in general accordance with WSDOT/APWA Standard specifications section 7- 02.3(3), which should be consulted for additional details. ' Sewer pipes installed above dense to very dense native soils, and supported thoroughly by compacted pipe bedding material, are anticipated to settle less than one inch during deactivation of the dewatering systems and filling of the pipes. Compaction Criteria: Using the Modified Proctor test (ASTM:D-1557) as a standard, we recommend that structural fill used for various on-site applications be compacted to the following minimum densities: ' Minimum Fill Application Compaction General Fill - Non-structural areas 90 percent Concrete sidewalk subgrade 90 percent Asphalt pavement base and subbase 95 percent ' Asphalt pavement subgrade (upper 4 feet) 95 percent Asphalt pavement subgrade (below 4 feet) 90 percent Overexcavations below utilities 90 percent 5—a Temporary Sloes t Temporary excavation slopes may be used in lieu of shoring where the necessary space is available and provided that existing structures, roadways, utilities or other sensitive elements would not be adversely impacted. Slope stability during excavation is a function of many ' factors, including: the presence and abundance of surface and groundwater; type and density of various soil strata; the depth of the cut; surcharge loading adjacent to the excavation, and the length of time the excavation remains open. ' Consequently, it is exceedingly difficult to preestablish safe and maintenance free temporary slope angles. Temporary slope stability should be made the responsibility of the contractor, who is continuously on the job site and able to observe changes in the site soil and groundwater conditions and monitor the performance of the excavation. We recommend that ' excavations be adequately sloped or braced to prevent injury of workman from local sloughing and spalling. All cuts should be completed in accordance with applicable Federal, State, and local safety provisions and codes, including current OSHA and WISHA guidelines. For planning purposes, temporary cut slope inclinations on the order of 1.5H:1 V (Horizontal:Vertical) should be planned in loose to dense sand and gravelly sand at least 2 feet ' above the groundwater level. Temporary unshored excavations are not recommended less than 2 feet above the groundwater level. Particularly loose soil conditions, such as those observed shallower than about 10 feet in boring B-3, could require flatter cut slope angles, on the order of 2H:1 V (Horizontal:Vertical). Perched groundwater conditions in the sidewalls of sloped 6-91 7-1 ozaz-e.1 oa t ' R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 16 ' excavations may require substantially flatter cut slope angles or additional dewatering to achieve stable temporary excavation side slopes. ' Permanent slopes above anticipated groundwater and surface water levels should be ' constructed at inclinations of 2H:1 V (Horizontal:Vertical) or flatter, and should be provided with deep-rooted, prolific ground cover as soon as possible after construction. ' 5 4 Dewatering Considerations Open excavations for pipeline construction and microtunneling staging pits below the water table will require dewatering to provide a stable excavation base and to facilitate construction activities. Six of the nine hollow stem auger explorations encountered groundwater above the planned pipe invert elevation. Groundwater levels should be expected to fluctuate. We recommend that dewatering be specified within the site soils to a depth of at least 2 feet below anticipated base of excavation elevation. Such dewatering could minimize unstable conditions and disturbance of the trench bottom, thereby reducing post-construction pipe ' settlements and providing a more stable pipe foundation. It should be realized that dewatering can cause ground settlement due to an increase in the effective stress of the dewatered soils. We recommend that the condition of the roadways and other adjacent structures be well documented prior to the start of construction, as described in the shoring monitoring section of this report. ' Dewatering activities could also affect the functioning of nearby groundwater wells or other uses of groundwater resources nearby. Adverse effects such as increased turbidity, decreased or eliminated well productivity, and general disruption of natural groundwater flow patterns are possible. Such effects could be either temporary or permanent. A thorough analysis of effects of project dewatering on the existing groundwater conditions would require one or more aquifer pump tests, which were beyond the scope of this study. We anticipate that dewaterin will be required along most areas of open cut excavations. At P 9 q 9 P locations where the pipe invert is less than 4 feet below the static groundwater level, we recommend dewatering through pumped sumps within the excavation. Sumps could consist of open pits within the excavation, or could consist of perforated steel drums filled with washed drain rock enclosing a pump intake to reduce clogging of the pump. Sump spacing should be determined based on field observations at the time of construction. In areas where the pipe invert elevation is more than 4 feet below static water levels, pumped dewatering wells should be used. Detailed layout of well diameter, spacing, pumping rates, and well depths requires either performance testing in the field at the time of construction or aquifer ' pump testing. Aquifer pump testing was beyond the scope of this study. We therefore recommend that the project be provided with performance based specifications for dewatering. Subsurface information contained in this report, along with soil permeability estimates 6-e17-102e2-e.10e ' R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 17 presented below could be used by bidders to develop a preliminary dewatering plan that could be adjusted based on performance observations at the time of construction. We recommend that final dewatering system design be made the responsibility of the contractor. For preliminary design purposes, the following table presents our estimated ' permeability values for some of the soil samples recovered from our borings. These permeability estimates are based on the grain size analyses completed for this study and ' methodology as outlined in the manual Department of the Navy NAVFAC P-418 Dewatering and Groundwater Control. ' TABLE 4 ESTIMATED SOIL PERMEABILITY VALUES Depth Estimated Permeability Boring Number Sample Number (ft) (cm/sec) B-1 S-7 13 Y2 6 x 10-5 B-1 S-15 30'/z 2 x 10-5 ' B-2 S-5 16'/z 6 x 10-5 B-2 S-13 28'/2 2 x 10-5 ' B-3 S-10 24 3 x 10-4 B-4 S-14 41 '/z 3 x 10-6 ' B-4 S-19 49 2 x 10-5 B-5 S-10 24 2 x 10-4 B-6 S-6 8 2 x 10-4 B-9 S-3 15 4 x 10-2 B-9 S-6 22'/z 4 x 10-2 ' B-10 S-2 10 4 x 10-2 B-10 S-8 32'/2 2 x 10-' Dewatering activities will generate significant quantities and flow of groundwater. The water ' is likely to be turbid and unsuitable for discharge into storm drainage systems without prior treatment. Provisions should be made to collect and clarify dewatering fluid prior to discharging from the site. s-sn-io292-a.ioa f fR.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 18 f5-,5 Excavation Shoring In areas where open excavations are planned for pipeline construction and space constraints fdo not allow adequate sloping of excavation sidewalls as recommended previously, excavation shoring will be required. Shoring types that would be well suited to this site include trench box or braced sheet pile shoring. ' 5.5.1 Slip Box Shoring ' Slip box shoring could be used where significant surcharges or sensitive structures are not located within a zone extending upward and outward from the base of the excavation at an angle of 1 H:1 V (Horizontal:Vertical). Temporary unsupported excavations are required to allow f placement of the trench box (or the first trench box if multiple boxes are used), and disturbance within that area is possible while the excavation is unsupported. If multiple trench boxes are stacked vertically one above another, the first trench box should be placed when the excavation f is 'one box" deep, and subsequent boxes should be added by forcing the first box downward as the excavation progresses and adding new boxes to the top of the stack, closest to the ground surface. Other procedures could result in disturbance in a wider area than 1 H:1 V f (Horizontal:Vertical). Trench boxes should be designed to support the same lateral earth pressures as recommended below for sheet pile shoring, should be used only in excavations with adequate dewatering, and should be in place before worker access into excavations where fshoring is required. 5.5.2 Sheet Pile Shoring f We recommend that the contractor be made responsible for design and construction of temporary excavation shoring, based on the following soil parameters. These soil parameters could also be applied to other types of shoring such as soldier piles with lagging. The following factive and at rest lateral earth pressures assume drained conditions (groundwater level at least 2 feet below the base of the excavation), static (non - seismic) conditions, and no surcharges with a lateral distance equal to the shoring depth at any given point. Surcharges may include fconstruction equipment or stockpiled materials, structures, roadways, slopes, or utilities. Allowances should be added for such surcharges, as described subsequently. Shoring that is f free to deflect at the top a distance equal to 0.01 times the height of the retained cut should be assumed to mobilize active earth pressures. Shoring designed using active earth pressures will allow vertical settlement behind the shoring approximately equivalent to 0.01 H, where H is the wall height. The maximum settlement effects will extend outward from the shoring a distance approximately equal to the height of the retained cut, at which point the effects will gradually diminish with increasing distance from the shoring. Active earth pressure for the site ' soils under the given conditions should be taken as 35 pounds per cubic foot (pcf), expressed as and equivalent fluid weight. f Shoring that is restrained from lateral deflection at the top should be designed with at rest lateral earth pressures. At rest pressures theoretically assume no horizontal movement of the shoring, and therefore no settlement effects in the retained cut. In reality, some deflection and fsettlement of the retained soils should be anticipated due to the fact that it is not possible to 6-917-10292-8.108 1 ' R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 19 ' construct a perfectly rigid shoring system. Shoring that is constructed closer than two times the distance of the retained cut from settlement sensitive structures should be designed using at rest lateral earth pressures. Where settlement sensitive structures are located near the planned excavations, a program of adjacent structure monitoring should be developed, as described subsequently. At rest lateral earth pressures under drained, static conditions should ' be taken as 55 pcf, expressed as an equivalent fluid weight. Sheet pile shoring design will require the use of internal cross braces to resist lateral loads in deeper excavations. For ' internally braced sheet pile shoring, at-rest lateral pressures should be used. Shoring of undrained excavations is not recommended; however, if undrained soil conditions ' occur behind shoring walls, we anticipate that active and at-rest lateral earth pressures of 85 pcf and 95 pcf, respectively, will be present. ' Surcharges should be added to the above referenced lateral earth pressures to accommodate construction equipment and supplies, roadways, or structures. Figure 3, Surcharge Pressures Acting on Adjacent Shoring or Subsurface Walls, provides recommendations for determining lateral earth pressures which correspond with specific surcharge conditions. Where cut and cover construction crosses Kennydale Lions Park, trench excavations may be positioned immediately east of the slope which rises to Aberdeen Avenue Northeast at an inclination of 2H:1 V (Horizontal:Vertical). In this particular surcharge situation, a total active earth pressure equivalent to 60 pcf and at rest earth pressure of 100 pcf, expressed as equivalent fluid weights, should be used. If excavations are offset a distance equal to the trench depth away ' from the slope toe, the lower lateral pressures presented previously can be used for shoring design. These ultimate earth pressure values assume drained subsurface conditions in the retained cuts. In the case of sheet pile or soldier pile and lagging shoring, resistance to active and at rest lateral earth pressures will be achieved as a result of passive resistance against the portion of ' the piles embedded below the excavation base. The following passive resistance value is based on saturated soil conditions below the excavation base. An ultimate passive resistance of 190 pcf should be used. An appropriate factor of safety should be applied by the shoring designer to obtain a suitable allowable passive earth pressure. Passive resistance within the uppermost 2 feet below the base of the excavation should be neglected. 5.6 Shoring Monitoring When excavations or tunnels are made below the level of existing buildings, utilities or other ' deflection-sensitive structures, there is risk of damage even if a well-designed shoring system has been installed. Dewatering activities have the potential to cause similar settlement effects. We recommend, therefore, that a systematic program of observations be conducted during the ' project construction phase to document the effects of construction on adjacent facilities and structures. We believe that such a program is advisable for two reasons. First, if excessive movement is detected sufficiently early, it may be possible to undertake remedial measures which could prevent or preclude serious or further damage to existing facilities or structures. 6-917-10292-B.108 ' R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 20 ' Secondly, in the unlikely event that problems do arise, the responsibility for damage may be established more equitably if the cause and extent of the damage can be closely defined. ' The monitoring Pro ram should include measurements of the horizontal and vertical movements 9 ' of the adjacent structures and the shoring system itself. At least two reference lines should be established adjacent to the excavation at horizontal distances back from the excavation face of about '/3H and H, where "H" is the final excavation height. Monitoring of the shoring system ' should include measurements of vertical and horizontal movements at the top of the shoring approximately 5 feet on center. If local perched groundwater conditions are noted within the excavation sidewalls, additional monitoring points should be established at the direction of the ' soils engineer. The measuring system used for shoring monitoring should have vertical and horizontal accuracy of at least 0.01 foot. All reference points on existing structures should be installed prior to construction, and survey readings taken thereafter will depend on the results ' of previous readings and the rate of construction. As a minimum, readings should be taken about once a week throughout construction until the temporary excavations are completed and backfilled. Such readings should be reviewed by the geotechnical engineer as construction ' progresses. In order to establish the condition of existing facilities prior to construction, we recommend that ' the owner and/or his representative make a complete inspection of pavements, structures, utilities and other relevant facilities near the project site. This inspection should be directed towards documenting any existing signs of damage, particularly those caused by previous ' settlement or lateral movement. The observations should be documented by pictures, notes, survey drawings or other means of verification. The contractor should also establish the existing conditions prior to construction for his own records. r 5 7 Microtunneling ' Microtunneling would be used for portions of the project along alignment 1 A deeper than 25 feet. These sections may require installation of pipes with invert elevations up to approximately 52.5 feet below existing grades. Although both storm and sanitary sewers would be constructed along the alignment, we anticipate that construction of both utilities in a single microtunnel would be more cost effective than construction of two separate microtunnels. Microtunneling is a method which incorporates remotely controlled, guided pipe jacking to advance a pipe along a specified path, to a specified location. Microtunneling is a specialized discipline, which should be performed only by a contractor with purpose-designed equipment ' and with established experience including successful completion of several similar projects. Prequalification of bidders is recommended. We anticipate that jacking and receiving pits will be required for staging of microtunneling equipment. The pits will probably entail shoring constructed with sheet piles or soldier piles, and temporary excavation dewatering will be required at the pit locations. The pit shoring should be designed using the shoring recommendations found elsewhere in this report. 8-1117-10M-8.108 R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 21 ' Subsurface soil conditions at the site are described above and on the boring logs. We anticipate that dense to very dense sand and silty sand with varying gravel content will be encountered in the tunneling zone, and that groundwater levels up to approximately 40 feet above pipe invert elevation will be encountered in the planned tunneling zone. Based on the Tunnelmans ground classification system we anticipate that most of the soils encountered in ' the tunneling zone would be classified as "Running" below or within approximately 2 feet of the static groundwater level, and "Fast Raveling" above the groundwater level or where the 1 tunneling zone has been dewatered. The contractor should be aware that most of the soils encountered in planned tunneling zones are very dense, and difficult drilling conditions should be anticipated. Coarse gravel to large cobble sized rocks were rarely encountered in our ' borings, but are relatively common in the type of soils present in the project area. It is likely that the tunneling operation will encounter some larger rocks during tunneling. ' 53 Construction Monitoring Because the condition of existing structures along the alignment, as well as constructability and performance of the new utilities, depends on timely recognition and resolution of geotechnical ' issues during construction, geotechnical construction observation and testing should be considered an integral part of the construction process. Consequently, we recommend that AEE be retained to provide the following post-report services: 0 Review all construction plans and specifications to verify that our design criteria presented in this report have been properly integrated into the design (included in ' current scope of work); • Prepare a letter summarizing our review comments (if required); ' • Attend a pre-construction conference with the design team and contractor to discuss important geotechnically related construction issues; 1 • Observe dewaterin operations and confirm that dewaterin is g p g adequate to achieve ' a safe work environment and protection of adjacent structures; • Monitor the installation of temporary shoring to verify conformance with the ' construction plans and to document the contractor's procedures; • Review all shoring wall deflection data collected by the project surveyor; • Observe all exposed subgrades after completion of stripping and overexcavation to confirm that suitable soil conditions have been reached and to determine appropriate subgrade compaction methods; • Monitor the placement of all structural fill and test the compaction of structural fill soils to verify their conformance with the construction specifications; 8-917-10292-B.108 ' R.W. Beck, Inc. 6-91 M-10292-B 8 January 1997 Page 22 • Prepare a post-construction letter summarizing our field observations, inspections, and test results (if required). ' Upon request, we could submit a proposal for providing the construction monitoring, testing, 9 and inspection services itemized above. Such a proposal is best prepared after the project plans 1 and specifications have been approved for construction. 6.0 CLOSURE We appreciate the opportunity to be of service to you on this project. If you have any questions or comments regarding this report, or require further information after reviewing this ' report, please do not hesitate to call us. Respectfully submitted, ' AGRA Earth & Environmental, Inc. Bruce W. Guenzler Project Geologist 5. D q4Y AS A 153 ao ls' James S. Drans field, E. SJONAL S ' Vice President EXPIRES 12/ 19!�� BW D G/JS /I ad ' Enclosures: Figure 1, Location Map Figure 2, Site and Exploration Plan ' Figure 3, Surcharge Pressures Acting on Adjacent Shoring or Subsurface Walls Appendix A - Subsurface Exploration Procedures and Logs Appendix B - Laboratory Testing Procedures and Results Boring Logs B-1 Through B-11 Test Pit Logs TP-1 and TP-2 Hand Auger Boring Log HB-1 ' Laboratory Grain Size Reports 8-917-10292-8.1 OB ~SE 72ND� ., SE r rs, o� i`�.. / 115T S�zl � o 715T PL`t = <t-"~>. 4r SE <l ST TE 12 ST = H SE iSi t} S *e ; t HAZEP�IDOD SF�i :SE 73RD i 13( NE SOT 7 R0 •PL_ a S - C 2 SE - SE ?fiTH f W ST 'z `r `ST E' ==E ,75TH PL 44 / ST l•19 - � �-•�thy,., �Mp, - '^ r, W ` �o .n r �fti,y CEIN i NE 43RD SE=' 80TH %�'"ST ST _ - PL? 1120-0 g 11600 N;r 31BSIESTx �+\�_\\ a si ST 1 1 U Z I S ^ N Pty \�� tw V Fex!n,n t 40 SE 83RDJ i S`�.~�-, in a� cE83PD 6�tt �� is PART N ST ' N 40TH ST SE t 84TH ST , =SE; i Be q 6� 1300 SE 955-H\ N 38TH c ST o H< s� I SE a6Tx ST$ E o: ` c, of �l S j 2 •h, N 37TH ST > �t�•\Q�1�G ✓ SE 91Td iT`� m,-4 -_ _ .KEW-ALE i N 36TH ST < NE -» 36TH S SE ' •`� _��88TH- - ST 9f3t:a?ARK - 1800 w = �� 11600~ - Sf g N 35TH ST i v P vif 11g 3< ': ,Pt 't< 9lF/ > < >;s�A�ti� SE 89TH;ST DD t N 34TH <i ST N W <' zl N 33RD PL S 'z '__ -SSE 9-0TH-iST HAY �� I N NE 33RD SE 91ST ST CREEK ' N 33RD STt� � =t i 92ND Si ; f`1220U PK - -- -a -N-32N6-- S - --— --------—I - '� — ' r 700 N 31ST ST °, N 315E Sr I ST =<N t 30TH d ti MAY CREEK �' sE_ a3n0 S 700 N 29TH STI1300 �� P SITE CREEK PARKI 95TH � 4�2`r` J`�,y MAY :•12700 � m N 28TH PL s 5Ta PL - r NE 287E ST _ ri _28TH-- SF a-E 7TH ST T SEEP t ' }H S� < < I 27TH D =i kE ---27,y erx - `!`;a SIERRA ¢ C7 a• > W $3� �.a - L _ E 99TN HEIGHTS < z; w n c q� N 26TH ST s;t.I -0. `'< ```sJ' reN -- 100TH ST PARK z KENNYD LE z LIONSI NE- srx ST-- ,m I -T—i - Z4TH .STIi w N NE $ PARK• -'--ST- --'c/--------'� �_ `� 1700 W ... <; NE ?3RD PL - ` < SE J �: '>< z NE- , !NE N R ST SE 103RD STO- _ 23 22ND 2500 ' 2 � _< NE 21sT STto z o'S>of 22ND ST i 2 -1 400.,, t12900 ST Is r� <1 <s 'g xtsT ST� t —I{� SE 105TH', NE 20TH $ 2300 NE 20TH s _ y W+� t I Sr I Nip z } 1700 I zE �I Q� t i I < IIE tsrN vE >t >E NE 19TH ST ° " S W <; < NORTH=s tie L _i SE Q06TH STD; NE = wE: NE terN NE 18TH ST Hlf>H 13000 i i PARK < ME I� RIDE. 4 "E --- ---- - --- " NE W 16� -ST - -N 0� NE Trt sT— -- BOAT LAUNCH �- 2400 Z PLfO <_ N sTH PL —��NS T } 3a�z > 1 o NE Y < go$ W `. c7 <�Z > Wo - NE 14TH � <li Q Z 14TH o ST �� NE i31 PAL o JR HS < w 1 W> NE 14TH ST 3TNH ST GENE C N si W to �I NE 13TH ST W, z&a W NEWRUL f '�i� �iN 12TH c' eST IB "xg NE 12TH ST ' BEACH PARK NE \ t2100 2500 oz 9mf `ak r PL 34G0 Zt �: � 700 y NF s CWR7 i PE PO 'W \ t Q NE 11TH ''<i NE NE 1'TH t NE :1TH 5T ` I1THi $ N 10TH PE i NE z S PARK';f�� -- _ RI wz 330 NE Ip 0 :OrH DRAT LAUNCH �� i RIDE��; _ 3 z z� •F J t >SEE-- c BOEINGENTON \\\ �/ ? Z a NE 10TH ST 9nMtE CL 29p0 NE lOTHOTH ST - a^ NE 9TH PL 500 ' 8 PLANT F �/ Z >w NE < 9TH Si NE NE 8TH= LL F NE < F 'PARKO •E 3 o NE NE eTN - z CEDAR ` N TH ST = '< NE HiGH OS o ^ �;'� 8TM S� < RIVER I i 1 i 2100 PAyRK = NE 6� ��°Ow NEi 7TH ST< rRI 11NE_ 61N .1300- .- W.O. 6-9_tM-_1-0 _92-H EAST KENNYDALE INTERCEPTOR AG R A DESIGN _B�nc1>L_- .___ __ ALIGNMENT 1 AND ALIGNMENT 1A W RENTON, WASHINGTON Earth & Environmental DRAWN DMw W 11335 NE 122nd Way, Suite 100 DATE DEG 1996 LOCATION MAP < Kirkland, Washington, U.S.A. 98034 6918 SCALE N.T.S. FIGURE 1 c c0 a J 'j ;EA STING l t t/ r . .......... . EXISTING 4% . ........ EXtST'ING 7: .EXI TINS 6., -;`TP G MENT,IA MENT I 7 . .... ...... 1_4 1-n 7,7 .......... ........... t r A;'IJ M-99-7 1A 7 �z -Q L 1�j q ;L Lj f L J - ki 71 L L; B 2F: A vE-. N.E.' ........ . - -..Nwmm 05 womm wma B-2 000 'N GMENT 1 A OPTION S 41 ALIGNMENT, I EX A B-1 THRU LEGEND B-6 B-9, 13-1U,13-1 1 HB-1 EAST KENNYDALE INTERCEPTOR E HOLLOW STEM AUGER BORING NUMBER HAND BORING NUMBER AND APPROXIMATE W.O. 6-_q1M_-JD292-fB c ALIGNMENT 1 AND ALIGNMENT 1A 9 B AND APPROXIMATE LOCATION LOCATION DESIGN BWGI RENTON, WASHINGTON TP-2 > 6 c LU AGRA HIGHWAY AUGER SOIL BORING NUMBER !1� TEST PIT NUMBER AND APPROXIMATE DRAWN DMW AND APPROXIMATE LOCATION Earffi &Envirorynerdal LOCATION 11335 NE 122nd Way, Suite 100 DATE DEG 1996 SITE & EXPLORATION PLAN 1 NOTE: B-2, B-5 & B-10 CONTAIN OPEN STANDPIPE PIEZOMETERS Kirkland,Washington, U.S.A.98034-6918 SCALE N.T.S. FIGURE GROUND SURFACE ' ISOLATED FOOTING q ' o ?h = 0.64q(?—sin?cos2a) ?/2 ? NOTE: LEVEL OF APPLICATION OF SURCHARGE LOAD, q, ' D WOULD VARY FROM GROUND SURFACE (FRONT END LOADER) TO SOME DEPTH BELOW GROUND SURFACE (FOOTING). 1 � BASE OF EXCAVATION ' GROUND SURFACE CONTINUOUS FOOTING ' x = mD PARALLEL TO EXCAVATION LINE LOAD q PRESSURE (FOR m> 0.4) 0 t c li ?h=1.28q m2 n N D (m2+ n2)2 ?h D (FOR m< 0.4) ' _ q 0.2 n •h-- D (0.16 + n2)2 BASE OF EXCAVATION UNIFORM LOAD q UNIFORM LOAD DISTRIBUTION U W 0 7 w ?h= 0.4q m ?h N q = VERTICAL PRESSURE IN psf ci i ' z z U Z O � BASE OF EXCAVATION z J Q H Z FIGURE 3 s w W.O. 6-917-102928 EAST KENNYDALE OR ' �' ,AG R A DESIGN BWG ALIGNMENT a Earth &Environmental DRAWN JMR RENTON� WASHINGTON 11335 N.E. 122nd way, Suite 100 DATE APR 1996 SURCHARGE PRESSURE ACTING ON 1 Kirkland, WA, U.S.A. 98034-6918 N.T.S. a SCALE ADJACENT SHORING OR SUBSURFACE WALLS Appendix A 1 1 1 1 1 1 APPENDIX A iFIELD EXPLORATION PROCEDURES AND LOGS i 1 1 1 i i 1 1 1 1 1 8.917-10292-B.1011 1 1 ' APPENDIX A FIELD EXPLORATION PROCEDURES AND LOGS ' 6-91 M-10292-B ' Our field exploration program for this evaluation included nine hollow stem auger soil borings and two HiWay auger borings, one hand boring, and two test pits advanced at the project site. Observation wells were installed in three of these borings. The following text sections describe ' our procedures associated with these explorations. Descriptive logs of our explorations are enclosed in this appendix. Soil Boring Procedures Our exploratory borings were advanced with a hollow-stem auger, using truck-mounted and track-mounted drill rigs operated by independent drilling firms working under subcontract to ' AEE. An engineering geologist from our firm continuously observed the borings, logged the subsurface conditions, and collected representative soil samples. All samples were stored in watertight containers and later transported to our laboratory for further visual examination and ' testing. After each boring was completed, the borehole was backfilled with a mixture of bentonite chips and soil cuttings, and the surface was patched with asphalt or concrete (where appropriate). In three of the borings, the conventional backfilling procedure was replaced by ' construction of a observation well. ' Throughout the drilling operation, soil samples were obtained at 1 .5- to 5-foot depth intervals by means of the Standard Penetration Test (SPT) per ASTM:D-1586. This testing and sampling procedure consists of driving a standard 2-inch-diameter steel split-spoon sampler 18 inches ' into the soil with a 140-pound hammer free-falling 30 inches. The number of blows required to drive the sampler through each 6-inch interval is counted, and the total number of blows struck during the final 12 inches is recorded as the Standard Penetration Resistance, or "SPT ' blow count." If a total of 50 blows is struck within any 6-inch interval, the driving is stopped and the blow count is recorded as 50 blows for the actual penetration distance. The resulting Standard Penetration Resistance values indicate the relative density of granular soils and the ' relative consistency of cohesive soils. The enclosed boring logs describe the vertical sequence of soils and materials encountered in ' each boring, based primarily on our field classifications and supported by our subsequent laboratory examination and testing. Where a soil contact was observed to be gradational, our logs indicate the average contact depth. Where a soil type changed between sample intervals, ' we inferred the contact depth. Our logs also graphically indicate the blow count, sample type, sample number, and approximate depth of each soil sample obtained from the borings, as well as any laboratory tests performed on these soil samples. If any groundwater was encountered in a borehole, the approximate groundwater depth is depicted on the boring log. Groundwater depth estimates are typically based levels measured in observation wells when they are ' installed, or on the moisture content of soil samples, the wetted height on the drilling rods, and the water level measured in the borehole after the auger has been extracted. 6-917-10292-B.109 ' Appendix A Page 2 Observation Well Procedures Groundwater observation wells were installed in three of our hollow stem auger borings, B-2, B-5, and B-10. Our groundwater observation wells consist of 1-inch-diameter PVC pipe, the lower 5 to 10 feet of which is finely slotted. The annular space around and slightly above the slotted segment was backfilled with clean sand, and the upper portion of annulus was sealed ' with bentonite chips and concrete. A flush-mounted monument was placed over the top of each wellhead for protection. The as-built configuration of each observation well is illustrated on the respective boring log. Our logs also show any post-drilling groundwater levels measured in the wells, along with the date of measurement. HiWay Auger Soil Borings ' HiWay auger borings were completed using a truck - mounted auger system operated by a local drilling subcontractor. A HiWay auger consists of a 3 to 4 foot section of helical augers attached to the end of a telescoping rotating shaft. The auger is advanced into the soil while ' turning, and as the flights become full of soil cuttings, the rotation is stopped and the auger is removed from the hole to clear cuttings. No casing is used, and therefore such borings may be useful only where soil and groundwater conditions are conducive to stable "open hole" drilling methods. Typically, the augers are removed from the hole to clear cuttings every two or three feet of drill penetration. The test holes are logged by observing the rate of advance of the drilling tools, observing the drill cuttings, and observing the inside of the borings visually. ' HiWay auger boring logs are presented at the end of this report, and are based on the field logs and interpretation of the drilling activities. ' Hand Boring Procedures Our exploratory hand boring was advanced with a 3-inch-diameter hand auger operated by an AEE geologist, who logged the subsurface conditions and obtained representative soil samples. ' All samples were stored in watertight containers and later transported to our laboratory for further visual examination and testing. After the hand boring was completed, we backfilled the ' borehole with soil cuttings and tamped the surface. The relative density of granular soils and relative consistency of cohesive soils were generally ' estimated according to the drilling resistance encountered in each borehole. The enclosed hand boring log describes the vertical sequence of soils and materials encountered in the hand boring, based primarily on our field classifications and supported by our subsequent laboratory examination and testing. Where a soil contact was observed to be gradational, our logs indicate the average contact depth. Our log also indicates the approximate depth of any ' groundwater encountered in the borehole, as well as all sample numbers and sampling locations. 6-9 1 7-1 0292-B.108 ' Appendix A Page 3 ' Test Pit Procedures Our exploratory test pits were excavated with a track-mounted hoe operated by an independent ' firm working under subcontract to AEE. A geologist geotechnical from our firm continuously observed the test pit excavations, logged the subsurface conditions, and obtained representative soil samples. All samples were stored in watertight containers and later ' transported to our laboratory for further visual examination and testing. After we logged each test pit, the hoe operator backfilled it with excavated soils and tamped the surface. ' The enclosed test pit logs indicate the vertical sequence of soils and materials encountered in each test pit, based primarily on our field classifications and supported by our subsequent laboratory examination and testing. Where a soil contact was observed to be gradational or ' undulating, our logs indicate the average contact depth. We estimated the relative density and consistency of the in-situ soils by means of the excavation characteristics and the stability of the test pit sidewalls. Our logs also indicate the approximate depths of any sidewall caving or ' groundwater seepage observed in the test pits, as well as all sample numbers and sampling locations. 8-917-10292-B.108 PROJECT: East Kennydale Interceptor w.o. 6-977-70292B BORINGNO. B- 7 SOIL DESCRIPTION a a m z PENETRATION RESISTANCE Page 1 w w Location: South side of Kennydale Lions Park 2 a ! 2 o a of 2 q < < Z U 3 Standard Blows per foot Other Approximate ground surface elevation: 282 feet 0 10 20 so ao 50 TESTING 0 Gravel Surfacing Medium dense,moist,brown,fine gravelly, - -- - -- --- -- -- i medium to coarse SAND with some silt 7I S-1 5 i ----- - Grades with trace to no gravel and trace to j some silt S-2 - -- ---- ---------- ' 10 Grades to dense,wet --- - ----- ------------------- Grades to dense to very dense i S-4 1ATD 15 ---- Medium dense,wet to saturated,brown,silty fine S-5 -- ---- - - - - SAND ! ----- - ---- I Grades to dense with trace fine gravel S6 -Grades to very dense,with some gravel S-7 51 20 ----� ' ----- ------ -5 , L� ---------- Hard,damp,brown,fine sandy SILT with trace i S-9 fine gravel 60 -- ---- ---------------- Grades with trace to no gravel I S-10 ----------------- 25 �� S-11t - +—— ---- S-12 - ---- - T i 50/5' -- — Grades with trace fine gravel ~ ___.:- a - S-13 - -----�---- ------ (continued) S-14 11 50/6' 1 30 0 20 40 so 80 100 LEGEND MOISTURE CONTENT Observation well 00 ' c - SealPlastic limit Natural Liquid limit 2.00-inch OD split-spoon sample 0 I I w` PVC casing , AG RA ' m N/E No groundwater encountered Groundwater level at Earth & Environmental c 'I'D time of drilling W 11335 NE 122nd Way,Suite 100 .� Grain size analysis Screen Kirkland,Washington 98034-6918 a ' Drilling method: HSA Hammer type: Cothead Date drilled: 13 March 7996 Logged by: JCH PROJECT: East Kennydale Interceptor w.o- 6-977- 70292B BORING NO. B- I SOIL DESCRIPTION w s x o x PENETRATION RESISTANCE Page 2 te e' .5 m , LU C_ � Location: South side of Kennydole Lions Park a o ¢ — of 2 p ¢ 4 D a 3 Standard Blows per foot Other Approximate ground surface elevation: 282 feet ' Cn z v o 0 20 so ao gp TESTING ' 30 — — — - - SILT(as above) P, Y Y Y S-15Grades to hard,dam brown,sandy,cla e SILT with trace fine sand ! 50y6� 1 - S-16 - 7 - Grades with trace medium to fine sand T 1 - 55 6 S-17 35 Boring terminated at approximately - ---------- ; 35 feet I � i ----------------- ----- ----- - 40 ' ----- - 1 ---- - ---i �- 45 ---- 1 - � -- -----' 50 a ---- - --- -- --- ---- ----- j i -- -----. f -- I 55 � I - 1 -----; ----- --- - - I - - ---------------- ---- - --- --- --- -- ' 60 0 20 ao 60 80 100 LEGEND MOISTURE CONTENT Observation well c I I Plastic limit Natural Liquid limit 2 2.00-inch OD split-spoon sample Seal w PVC casing , A G R A N/E No groundwater encountered Groundwater level at Earth & Environmental C AD time of drilling W -T 11335 NE 122nd Way,Suite 100 Hydrometer analysis Screen Kirkland,Washington 98034-6918 ' Drilling method: HSA Hammer type: Cothead Date drilled: 73 March 1996 Logged by: JCH PROJECT: East Kennydale Interceptor w.o. 6-977- 70292B BORING NO. B-2 z .. SOIL DESCRIPTION o PENETRATION RESISTANCE G ° Z E- .Location: North part of Kennydale Lions Park 2 o a¢ � Q D a 3 Standard Blows per foot OtherApproximate ground surface elevation: 285 feet rn zc7 0 o zo 3o aot�TpL,�gl ESTING ' 0 Landscaping and Topsoil Very dense,damp,brown,fine,gravelly,medium - - - ------ ------------------ to coarse SAND - - { -----' S-1 62 5 — l S-2 ----I I ----� 55 =- - ----- ----- ----- 10 —1 ------ ---- ---------- ------------- -- -- - - --- -A-----' Medium dense,wet,brown,silty,fine SAND S-3 L ------ _-- '----------- 15 Grades to dense,silty,fine to medium SAND with /z5/96 some to trace gravel ' Becomes saturated 1 ATD --- ---- 1 S-5 - _ -----1----- - - Hard,moist,brown,fine to medium,sandy SILT S-6 i ' with trace fine grovel j ----------- .'-- I, I 20 — S-7 ' Grades with silty,fine to medium sand lensesl-2' a -.-.-_---------------I_-__.:-__--, thick which are saturated S-8 I ' - YO b. S-9 ——- S-10 { - -- - ---- ------------- Grades to gray,without saturated sand lenses 25 — S 11 - - ------ ----� ---- [ 70 6" 100/6' Grades to damp to moist � ----- 1 S-12 .- ------1 j - - - 50'. S-13 , -- /3�=j--- 30 (continued) 6 o zo 40 so 80 100 LEGEND MOISTURE CONTENT Observation well d ' c - I I Plastic limit Natural Liquid limit 2.00-inch OD split-spoon sample Seal w` PVC casing my AG R A m N/E No groundwater encountered Groundwater level at Earth & Environmental 1 w 'I'D time of drilling Observed groundwater level 11335 NE 122nd Way,Suite 100 Grain size analysis �� (0/00/00=on date indicated) Screen Kirkland,Washington 98034-6918 ' Drilling method: HSA Hammer type: Cothead Date drilled: 73 March 7996 Logged by: JCH PROJECT: East Kennydale Interceptor w.o. 6-9 77- 70292B BORING NO. B-2 S SOIL DESCRIPTION m o x PENETRATION RESISTANCE Page 2 m w Location: North part of Kennydole Lions Park 2 2 o ¢ . of 2 p ¢ Q Z) a 3 Standard Blows per foot Other Approximate ground surface elevation: 285 feet �' `" z 0 0 10 20 30 40 50 TESTING ' 30 SILT(as above) S-14 - - .. --- .. -. - 5 13" =' S-15 -- - - 50�6. - Boring terminated at approximately 33 feet 35 — — I - ---------- i-- - 1 -- ----- ----- - i ----------- - 40 __ _ h-- ----------- ------------ --- -- ---- ---- �I I ---- ----- -------- -----'--- 45 --- --- -- ---� ----- --- ............. - - -----1--- ------------------ 50 — -- --- -- ----'- --- ---- -- -�- -- ---- ----------- ---- ---- ----- - - -- --- - - - --- --- -- ----- ----- ----- 55 I - 1 ---------- --- ----- -- --- ---- i - -- -- - ---- ' 60 0 20 40 so ao 100 c LEGEND MOISTURE CONTENT Observation well C N ' C 2.00-inch OD split-spoon sample I I Seal Plastic limit Natural Liquid limit w PVC casing L, AG R A N/E No groundwater encountered Groundwater level at Earth & Environmental r A° time of drilling w 11335 NE 122nd Way,Suite 100 Screen Kirkland,Washington 98034-6918 a ' Drilling method: HSA Hammer type: Cothead Date drilled: 73 March 1996 Logged by: JCH PROJECT: East Kennydale Interceptor w.o. 6-9 7 7- 7 0292B BORING NO. B-3 ' T Y SOIL DESCRIPTION w w o PENETRATION RESISTANCE page 1 m Z � Ak Location: Aberdeen Avenue NE ° ! p ¢ of 2 p < a 3 Standard Blows per foot Other Approximate ground surface elevation: 278 feet Z v 0 10 20 30 40 50 TESTING ' 0 Asphalt Surfacing _ Gravel Fill Dense,moist,tan,gravelly,medium SAND with some silt(Fill) - ------- - S-1 J 1 - J I ' S Loose,damp to moist,red-brown,silty,fine to medium SAND with rootlets and charcoal(Fill or Disturbed Native) I = - - - '- - - S-2 ----- -----i----- ----------- ----- 10 Grades with thin silt horizons - ------------------- Medium dense to dense,damp,tan,fine to t _ medium SAND with trace silt 1 ---- --- S-3 15 Grades to dense,moist with wet zones,with trace J gravel S-4 ' Grades to moist with trace to some silt ----- ------------ -----i------ '-----i ----- --- r----------- I Grades to damp to moist S-6 ------------------ ----------- ------ 20 S-7 --- ----' - - --- ----- --- -- - 1 S-8 ---- - -- - - --- ...... ' _ S-9 ATD ----- -------- ---- ----------- Medium dense,wet to saturated,tan,gravelly, � .. 25 medium to coarse sand with some silt S-10J_ I — iStiff,wet,tan,fine to medium,sandy SILT with S-11 ----- ---i---- ' trace fine gravel Dense,wet,tan,silty,fine to medium SAND with I -----i---- S-12 ' trace gravel 1 ---- - ----- --- - -. ' — — -- -fi -- — Dense—,saturate——d,—tan, n e SAND Very dense,wet,tan,silty,fine to medium SAND 5-13 `------ ------- - --f - 30 with some gravel ' o (continued) 0 20 40 60 80 too LEGEND MOISTURE CONTENT Observation well v ' C - Plastic limit Natural Liquid limit 2.00-inch OD split-spoon sample 0 I I Seal w PVC casing AG R A m N/E No groundwater encountered -Ir Groundwater level at Earth & Environmental ' a A�D time ofdrilling W 11335 NE 122nd Way,Suite 100 Grain size analysis _ Screen Kirkland,Washington 98034-6918 Q Drilling method: HSA Hammer type: Cothead Date drilled: 14 March 7996 Logged by: DHG 1 PROJECT: East Kennydole Interceptor w.o. 6-917- 70292B BORING NO. B-3 SOIL DESCRIPTION LL, O z PENETRATION RESISTANCE Page 2 ,a Location: Aberdeen Avenue NE °y 22 p Q _ of 2 ¢ ¢ x 3 Standard Blows per foot Other Approximate ground surface elevation: 278 feet Cn z v o 10 zo 30 40 so TESTING 1 30 SAND(as above) S-14 50/6' AL Boring terminated at approximately 1 31 feet 1 35 I � a - --_- - - - - -- 40 1 - ---------- -- - ----------- 1 ----- ----------- ------ - 45 T ----- ----- i 1 -- -- ----- --- i --- I -- . 50 1 --------- 1 --- ---- 1 --- --- - -- ---- 55 - 1 T ----- ---- _ --- 1 I --- - -- ---- 1---- 1 60 0 20 40 60 80 100 c LEGEND MOISTURE CONTENT Observation well 1 = Plastic limit Natural Liquid limit 0 2.00-inch OD split-spoon sample I I Seal w PVC casing imp AG R A m N/E No groundwater encountered Groundwater level at AID time of drilling Earth & Environmental 1 r W 11335 NE 122nd Way,Suite 100 Screen Kirkland,Washington 98034-6918 1 Drilling method: HSA Hammer type: Cothead Date drilled: 73 March 7996 Logged by: JCH 1 PROJECT: East Kennydale Interceptor w.o. 6-917- 10292B BORING NO. B-4 SOIL DESCRIPTION W I m m o V. PENETRATION RESISTANCE page 1 m Location: Aberdeen Avenue NE&NE 27th Street 0.} o < of 2 in F Q : a 3 Standard Blows per foot Other Approximate ground surface elevation: 301 feet �' N z v TESTING 0 0 10 zo 110 40 so Asphalt Surfacing _ _ __ N/E Medium dense,damp,tan,fine SAND -----;- - -- - -------- ------- -- - __ ,__- --- _____,_______________ ___ _ ____ S 7 i i 5 � I -- I r- Grades with trace silt 1 1 s2 11 - - -- -' ....................... to - I Grades with trace to some silt i ------------- - -- - S-3 1 -------- ...... -- 15 i Grades with trace silt ----------- ---- - 1 --- -- ------- -- - ..................----- -------- --------- 1 - -- --- ---- •-------- - - 20 I -- - . ------------ - -- 1 ------ - S-5 25 - 1 Medium dense,wet,tan,silty,fine SAND to fine _ � ;_____ _____ ______________._,__......... sandy SILT with trace gravel - --- -- -- --•-•------- -(-- -- 1 S-6 - - (continued) 1 30 o zo ao e0 so 100 LEGEND MOISTURE CONTENT Observation well d 1 C _ 2.00-inch OD split-spoon sample I I Seal plastic limit Natural Liquid limit w PVC casing AG R A 1m rv/E No groundwater encountered �' Groundwater level at Earth & Environmental C AiD time of drilling w 11335 NE 122nd Way,Suite 100 W Screen Kirkland,Washington 98034-6918 a 1 Drilling method: HSA Hammer type: Cathead Date drilled: 74 March 1996 Logged by: DHG PROJECT: East Kennydale Interceptor w.o. 6-917- 70292B BORING NO. B-4 1 SOIL DESCRIPTION w m w a x PENETRATION RESISTANCE Page 2 Lu Location: Aberdeen Avenue NE&NE 27th Street 2 ° 22 p a — of 2 < n U 3 Standard Blows per foot Other Approximate ground surface elevation: 301 feet o 0 20 3o ao gp TESTING 30 Grades to very dense,sand gradation becomes finer S-7 J 50/6" j S-8 ---- - - -- -- -- --' S-9 75j6• i 35 --- - ' Grades with weak oxidation mottling a 1 I S-11 1 -- -- --- - - 50/5" - ----------------- Grades to tan,without noticeable mottling, 5-12 - -= ,-- igrades with lenses of saturated clean sand 40 Grades without clean sand seams,grades to wet ��roxmately 11'thick , S-1.3 I 50/6' g __ to saturated Grades to medium to coarse SAND with trace to T 1 ——— —— 5-14— no gravel , i-• � - -- ...... -j- g -----'-------- .. --------------- Grades to moist,with trace to some ravel S-15 70 ------ ---------- ------ --- 45 t�;i S-16 1 ! 65/6' I S-17 ' ; 6014— ---- --- 1 Grades to gray T S-18 16 ------ ----- _85 -- 50 1-1 ' S-20 ---------- -70/6------ Grades with silt horizons ------------. S-21 j i 90/6' T S-22 -----j 60 55 S-23 70/5' 75/6" t 9 57 feet PP - -----,- --j,-----,- ------• I- ---- - - - -- Boring terminated at a roximatelY 60 U o zo ao so too S MOISTURE CONTENT LEGEND Observation well 2 -- 0 2.00-inch OD split-spoon sample I I Seal Plastic limit Natural Liquid limit w PVC casing , A G R A ' N/E No groundwater encountered Groundwater level at Earth & Environmental c A10. time of drilling w 11335 NE 122nd Way,Suite 100 a - Grain size analysis Screen Kirkland,Washington 98034-6918 < a ' Drilling method: HSA Hammer type: Cothead Date drilled: 13 March 1996 Logged by: JCH PROJECT: East Kennydale Interceptor w.o. 6-977- 70292B BORING NO. B-5 ' = y SOIL DESCRIPTION j o PENETRATION RESISTANCE Page I m w Location: NE 27th Street °� 22 p a . of 2 Q ¢ ¢ : a 3 Standard Blows per foot Other Approximate ground surface elevation: 270 feet Cr z U 0 10 20 so 40 so TESTING ' 0 Asphalt Surfacing 8175196 Grovel Base - - - Loose to medium dense,damp,brown,fine to - - - - -- - medium SAND with trace to some silt IT I S-1 ' 5 -- - I � - ------------------ - - ------ Grades to medium dense,fine sand gradation ----------------- -- ---- S-2 -- -- - i - ------ -10 -- -- S-3 __ S-4 15 - Grades to damp to moist S-5 --- S-6 a Grades to damp S-7 20 — - --------------------a---------- ---- I - I Grades with trace to some silt S-8 - - ATD ------------------- ' S-9 . -. Grades to saturated S 10_ 2`5 4/23/96 —— —————- 11/23/96 Grades with trace fine gravel S-11 _--------------.... ------------_ j i _ - Interbedded medium dense to S-12 ...... dense,saturated, ! i tan,silty,fine SAND and very stiff to hard,wet to - -- ---------- = - saturated,tan,fine sandy SILT I S 13 30 (continued) 0 20 40 ee ao ,00 LEGEND MOISTURE CONTENT Observation well ' o _ 2.00-inch OD split-spoon sample I I Seal Plastic limit Natural Liquid limit w` PVC casing AG R A ' N/E No groundwater encountered IV Groundwater level at Earth & Environmental r AID time of drilling ¢ Observed groundwater level Screen 11335 NE 122nd Way,Suite 100 =_ Grain size analysis 2MM (0/00/00=on date indicated) -- Kirkland,Washington 98034-6918 c� n Q ' Drilling method: HSA Hammer type: Cothead Date drilled: 75 March 1996 Logged by: DHG PROJECT: East Kennydale Interceptor w.o. 6-917- 70292B BORING NO. B-5 SOIL DESCRIPTION m w w o PENETRATION RESISTANCE Pave 2 = m o w Location: NE27th Street p ¢ p of 2 Approximate ground surface elevation: 270 feet � z v 3 Standard Blows er foot Other a to zo 30 40 sa TESTING 30 Interbedded SAND and SILT (as above) S-14 --Verydense,wet,tan,silty,fine to medium SAND - ------ - ------ with some gravel S-16 50/6' *> 35 Boring terminated at approximately 34 feet - --- � I j J -------------- - ----- ------ ----- ------ -- - 45 1 - - - { ---------- ----'. -----.---- . --- I 50 —I 1 ; ----- - ----------- ----- i -� i i 1 -- J - ---- -J -- - a 55 ----- 1 - j ----- --- y _______________ ________________________________ i � - 60 �j V 20 40 60 80 100 LEGEND MOISTURE CONTENT Observation well 1 � 0 2.00-inch OD split-spoon sample I I Seal Plastic limit Natural Liquid limit A w PVC using AG R A NIE No groundwater encountered Groundwater level at Earth & Environmental r A10: time of drilling W 11335 NE 122nd Way,Suite 100 Screen Kirkland,Washington 98034-6918 Q ' Drilling method: HSA Hammer type: Cotheod Date drilled: 15 March 1996 Logged by: DHG PROJECT: EastKennydale Interceptor w.o. 6-977- 70292B BORINGNO. B-6 SOIL DESCRIPTION o PENETRATION RESISTANCE Page 1 Ak Location: NE 27th Street p ¢ of 1 3 Standard Blows per foot Other Approximate ground surface elevation: 243 feet �' z t7 0 10 20 N 40 so TESTING ' 0 Asphalt Surfacing Gravel Base . ..... ---- --- -; — S-I 82AL ' Medium dense,damp to moist,brown,fine to medium SAND with some gravel and trace SILT -- --•---- (Fill) S-2 � • � 5 _ S-3 — ' Grades to wet -- - - --- ----- -S-4 - Medium dense,saturated,tan,silty,fine SAND __- __ - -.-_,_ with some silt S 5 A D AL ' 10 —— ————- - S-6 C Grades to reddish tan,with some silt i S-7 ---- -----,---- ___ ____ Grades to mottled orange,silty S-8 F - --------=--- S-9 -- -- ---------. - -------- --- ------- 15 Boring terminated of approximately � 14 feet - --- - -- --- . --. - -- ----- ----- --- - - I ----- -----I---- --- 1 -----f -- 20 — ------ j i ------ ---1----------- - --- --- -- - --- ----- --- 25 -- --- ---- --------- I - ' 30 0 20 40 ea e0 100 LEGEND MOISTURE CONTENT Observation well 1 0 _ 2.00-inch OD split-spoon sample I I Seal Plastic limit Natural Liquid limit .5 w PVC casing P a A G R A ' M N/E No groundwater encountered Groundwater level at Earth & Environmental time of drilling w 11335 NE 122nd Way,Suite 100 Grain size analvsis — Screen Kirkland,Washington 98034-6918 a ' Drilling method: HSA Hammer type: Cothead Date drilled: 75 March 7996 Logged by: DHG 1 HIWAY AUGER BORING LOGS 6-91 M-1029 2-B Depth (feet) Material Description Sample No. HiWav Auger Boring B-7 ' Location: South side of N.E. 27th Street Approximate ground surface elevation: 243 feet 0 - '/2 Topsoil and sod. %2 - 6'/2 Medium dense, moist, dark brown, silty, gravelly, fine to coarse ' SAND, scattered cobbles, and one boulder. 6'/2 - 14 Medium dense, wet, mottled gray and brown, fine SAND, some silt to silty, some to trace fine to medium gravel. Grades with trace to Isome silt below 10/z feet. Grades to saturated below 8.0 feet. Boring terminated at approximately 14 feet due to caving. Moderate to severe seepage below 8 feet. Moderate to severe caving from 10 to 14 feet. HiWay Auger Boring B-8 Location: North end of Kennydale Lions Park Approximate ground surface elevation: 285 feet 0 - '/2 Gravel surfacing. '/2 - 4 Loose to medium dense, damp, dark brown, gray, fine SAND, trace to some silt, trace fine gravel (Fill). 4 - 11 Medium dense, moist, tan and gray, fine SAND, trace to some silt, trace fine gravel. 11 - 14 Medium dense, damp, gray, fine to coarse sandy GRAVEL, trace silt. Boring terminated at approximately 14 feet due to caving. Moderate to severe caving below 8 feet. No seepage observed. Date drilled: 4 April 1996 Logged by: BWG ' 10282.HA8 PROJECT: East Kennydale Interceptor w.0. 6-977- 70292B BORINGNO. B-9 ' SOIL DESCRIPTION wa . o w PENETRATION RESISTANCE page 1 w , m°F .- w Location: Pasture area � o, I � � ' p � _ of 1 p ¢ ¢ rG 3 Standard Blows per foot Other Approximate ground surface elevation: 254 feet z v 0 Grass and Topsoil o o zo 30 ao so TESTING ' Medium dense,dam brown-and gray,fine to P• 9 Y �-----= coarse,sandy GRAVEL with some silt and trace cobbles ! -. --- ----------- ----- ---- - ------ ------ ----- ----- I i f- 5 a S-1 - ---- --- --- - ----- ' -----=----- - -- Loose,damp to moist,brown,fine to coarse - 10 SAND with some fine gravel and trace silt I S-2 1 1 _ _, , ---- - Grades to saturated,with trace ravel and some ATD - silt,moderately dilatant g ,il F---------- 15 j I S-3 ----- -- Grades to medium dense I-- 1 1 ----- - ----- S-4 I 20 1 I — --- --- , i S-5 - r-----G- ' S-6 I ----- 25 Boring terminated at approximately - 24 feet ----------'---- I -------- ' 30 o zo ao eo 80 100 LEGEND MOISTURE CONTENT Observation well 1 P — 0 2.00-inch OD split-spoon sample I I Seal Plastic limit Natural Liquid limit w PVC casing AG RA ' N/E No groundwater encountered Groundwater level at Earth & Environmental r AtD time of drilling W 11335 NE 122nd Way,Suite 100 W �HEE) Grain size analysis — Green Kirkland,Washington 98034-6918 ¢ ' Drilling method: HSA Hammer type: Automatic Date drilled: 18 November 1996 Logged by: BWG PROJECT: East Kennydale Interceptor w.o. 6-917- 10292E BORING NO. B- 70 SOIL DESCRIPTION 1 a m o a PENETRATION RESISTANCE Page 1 � 0 am a � '' o , oft tj w Location: Pasture area — p I !, a 3 Standard Blows per foot Other Approximate ground surface elevation: 262 feet �' z v o 0 20 30 ao so TESTING 1 0 Topsoil and Grass — -- — —— ——— - Loose,damp,gray,silty,fine SAND with trace to some fine gravel(Fill) , l _ --- ---------- - ._ -------- 5 S-1 + �_ -- -1 -- ---- I -------- I —, ---------- ----- ---------- -----� ' Medium dense,damp to moist,brown,fine to 10 coarse,sandy,fine to coarse GRAVEL with trace Silt S-2 -1----------- - �..... ........... --- r ----- ----- ---- , ... . _.. 15 Grades to fine to medium GRAVEL71 �- S-3 1 ----- - --- ---- 11/23/96 ---- ` `----7 -- Grades with trace cobbles ---- -- 20 ' s-a J ---------------- -- ----- 1 ATD I , ' Medium dense,saturated,brown,fine SAND with 1 --- trace silt,trace fine gravel and moderately - ----------- -----=----- -----=------ dilatont 25 ---- I ' S-5 a 1 { ----- ---------- Sand is coarser,still fine gravel S-6 A- (continued) ' 30 0 20 ao so 80 100 LEGEND MOISTURE CONTENT Observation well d 1 C _ 2.00-inch OD split-spoon sample I Seal Plastic limit Natural Liquid limit w PVC casing ft AG RA N/E No groundwater encountered Groundwater level at Earth & Environmental ' r A1l time of drilling w 11335 NE 122nd Way,Suite 100 Grain size analysis Screen Kirkland,Washington 98034-6918 a Drilling method: HSA Hammer type: Automatic Date drilled: 18 November 7996 Logged by: BWG PROJECT: East Kennydale Interceptor w.o. 6-917- 10292B BORING NO. B- 70 _ .. SOIL DESCRIPTION W m w 2 ,4 PENETRATION RESISTANCE Page 2 WW j07 zW Location: Pasture area ° 2 2 c ¢ _ of 2 p ¢ Q Z a 3 Standard Blows per foot Other Approximate ground surface elevation: 262 feet �' Crz v o 0 20 30 40 50 TESTING 30 Fine SAND(as above) S-7 a --------- --- ----- -fir; I; --, ,, ------ ---- S-8 i- -- ----i ---1 -- 35 S-9 - I ---------!------------------------1- Boring terminated at approximately 36.5 feet -----------i-----=----- -----I------ { -------- -- - --- --- --- - ' 40 i II ----- -- - -- - 1 ; 1 -- -- -------- - 45 7 � I, 1 , r----- -----' 1 ---- ---- -- 1 , j ------- --- -- {----------- --- ----- --- - 50 -- ----------- I --- ----- ----- ----------- 1 1 ---- --- - -- - -- - -- - 55 1 ---- --- -- ----- -- - --- - --------- 1 60 0 20 40 eo ao 00 LEGEND MOISTURE CONTENT Observation well Plastic limit Natural Liquid limit 0 2.00-inch OD split-spoon sample I I Seal 9 w PVC casing , AG R A v ' N/E No groundwater encountered Groundwater level at Earth & Environmental c AD time of drilling w 11335 NE 122nd Way,Suite 100 Grain size analysis Green Kirkland,Washington 98034-6918 a ' Drilling method: HSA Hammer type: Automatic Date drilled: 18 November 7996 Logged by: BWG PROJECT: East Kennydale Interceptor w.o. 6-9 77- 70292-B BORING NO. B- 7 7 SOIL DESCRIPTION m 0 � PENETRATION RESISTANCE z page t � Location: Gravel driveway m2 2 p ¢ of 1 0 ¢ ¢ :) C 3 Standard Blows per foot Other Approximate ground surface elevation: 275 feet z v p 10 zo 30 ao so TESTING 0 Topsoil and Grass N/E Loose,damp, tan,fine SAND with trace fine - - - grovel and silt 5 S-1 — — - ——— --- — ——— -- — — - Medium dense,damp,brown,fine to medium SAND with some gravel to gravelly and trace silt h ----...-- - 1 10 I - ----- 1 J - Medium dense,damp,gray,silty,fine SAND with _ ____ ------- ---- - trace gravel I S-3 --- ------ 15 i S-4 t — :----- Very dense,moist,gray,silty,fine SAND with trace to some fine gravel(Glacial Till) -- � S-5 I ' 1 55 , i----------------------- � I 20 — — I S-6 50 Boring terminated at approximately ---- 21 feet - 1 ----- -- --- . 25 —, - a �I , i ---- -- - ------- ------- ---- - -----'�-----j- ----'---- --------------------I---------- I ' 30 o zo ao eo so ioo LEGEND MOISTURE CONTENT Observation well C 2.00-inch OD split-spoon sample I I Seal Plastic limit Natural Liquid limit w PVC casing , AG R A m N/E No groundwater encountered Groundwater level at Earth & Environmental ' c "ro time of drilling w 11335 NE 122nd Way,Suite 100 a =— Grain size analysis _ Screen Kirkland,Washington 98034-6918 a ' Drilling method: HSA Hammer type: Automatic Date drilled: 78 November 1996 Logged by: BWG ' TEST PIT BORING LOGS 6-91 M-10292-B Depth (feet) Material Description Sample No. TP-1 1 Location: Wooded Area Approximate ground surface elevation: 265 feet 0 - % Topsoil and sod. - 6 Loose to medium dense, damp, brown, fine SAND, some silt trace fine gravel, trace garbage (plastic, metal, etc.) (Fill) 6 - 7 Loose to medium, damp, light brown, fine SAND, trace silt, trace fine gravel. 7 - 8% Medium dense, damp, gray and mottled gray, gravelly fine SAND, trace silt. 8'/2 - 16 Medium dense, damp, gray and mottled gray, fine SAND, trace rgravel, trace to some silt. Boring terminated at approximately 16 feet. ' No seepage. Moderate to severe caving from 0 to 12 feet. ' TP-2 Location: Wooded Area Approximate ground surface elevation: 265 feet 0 - 1 Topsoil and roots. 1 - 4 Loose to medium, damp, light brown, fine SAND, trace to some fine gravel, trace silt. 4 - 10 Medium dense, damp, light brown, fine SAND, some fine gravel, trace silt. Boring terminated at approximately 10 feet. ' Moderate caving from 0 to 10 feet. No seepage observed. Date drilled: 15 November 1996 Logged by: BWG 10292-TP.103 HAND AUGER BORING LOGS 6-91 M-10292-B Depth feet Material Description Sample No. Hand Auger Boring Location: Boggy Area Approximate ground surface elevation: 243 feet 0 - 1 % Saturated organic topsoil. 1 1/2 - 3 Loose, saturated, fine SAND, trace to some silt, trace fine gravel. Boring terminated at approximately 3 feet. Strong groundwater seepage from 0 to 3 feet. Moderate caving/flowing from 0 to 3 feet. ' Date drilled: 25 November 1996 Logged by: BWG 10282-HA.103 Appendix B 1 i i APPENDIX B iLABORATORY TESTING PROCEDURES AND RESULTS i 1 1 1 i 1 APPENDIX B LABORATORY TESTING PROCEDURES AND RESULTS 6-91 M-10292-B Our laboratory testing program for this evaluation included numerous visual classifications, 13 moisture content determinations, and 13 grain size analyses. The following text sections describe our procedures associated with each type of test. Graphical results of certain ' laboratory tests are enclosed in this appendix. Visual Classification Procedures Soil descriptions included in this report are generally based on the Unified Soil Classification System (USCS). The USCS classifies granular soils (those soils composed primarily of soil ' grains larger than the U. S. No. 200 Sieve) based on textural characteristics, while soils composed primarily of "fines" (soil grains finer than the U. S. No. 200 Sieve) are classified based on their plasticity and compressibility characteristics. ' Most of the soil descriptions contained in the text of this report,and in the exploration logs are based on estimates of the grain size distribution in a given granular soil sample or soil horizon ' gained through a visual evaluation of the sample or horizon. Since most of the soil descriptions are based on visual estimates of textural compositions, formal USCS classifications are not used. Use of formal USCS classifications to describe a given soil sample or horizon strongly ' implies that laboratory grain size data were utilized to place the soil into a narrowly defined grain size distribution description. ' Because formal USCS classifications are not used in our soil descriptions, an alternate description system is used. Within the AEE soil naming system, a full soil description includes the following: ' 1. Density of granular soils or Consistency of cohesive soils. May be based on SPT testing, ' estimates of the density based on difficulty of excavation, hand held testing instruments, or other data. Appendix B Page 2 Soil Density \ Consistency Descriptors ' Granular Soils Cohesive Soils (Majority coarser than No. 200 Sieve) (Majority Finer than No. 200 Sieve) ' Estimated or Density descriptor Estimated or Consistency measured SPT measured SPT Descriptor Blowcount range (N) Blowcount range (N) ' 0-4 Very Loose <2 Very Soft 5-10 Loose 2-4 Soft ' 11-30 Medium Dense 5-8 Medium Stiff ' 31-50 Dense 9-15 Stiff >50 Very Dense 16-30 Very Stiff ' >30 Hard 2. Moisture content; ' Soil Moisture Descriptors Descriptor Moisture Condition ' Dry Completely without Moisture Damp Very slight observable moisture ' Moist Approximately "optimum" for compaction purposes ' Wet Produces free water on shaking, wetter than "optimum" for compaction purposes ' Saturated Zero air voids, completely inundated with water ' 3. Color; ' 4. Primary grain size modifiers (adjective) indicating 12-35 percent by weight (e.g., gravelly or silty); ' 5. Major soil tyke, capitalized, indicating 35 percent or more by weight (e.g., SAND or SILT); 6-917-10292-8.108 ' Appendix B Page 3 6. Minor grain size modifiers (some 5-12 percent, trace 0-5 percent); ' 7. Descriptive modifiers (e.g., roots, fill debris, cemented); ' 8. General geologic description (e.g., Glacial Till). For example: ' Medium dense, moist, mottled gray-brown, silty, SAND with some gravel and scattered thin roots (Weathered glacial till). ' This describes a weathered glacial till soil with an estimated (or measured) SPT Blowcount of between 11 and 30, at a compactible moisture content, with 12 to 35 percent silt, 5 to 12 percent gravel, a few thin roots, and the balance made up with sand. Moisture Content Determination Procedures Moisture content determinations were performed on representative samples to aid in ' identification and correlation of soil types. All determinations were made in general accordance with ASTM:D-2216. The results of these tests are shown on the exploration logs in Appendix A. ' Grain Size Analysis Procedures A grain size analysis indicates the range of soil particle diameters included in a particular ' sample. Grain size analyses were performed on representative samples in general accordance with ASTM:D-422. The results of these tests are presented on the enclosed grain-size distribution graphs and were used in soil classifications shown on the exploration logs in ' Appendix A. ' 6-9 1 7-10292-8.1 08 GRAIN SIZE DISTRIBUTION ' SIZE OF OPENING IN INCHES U.S. STANDARD SIEVE SIZE HYDROMETER 36" 12" 6" 3" 1 1/2" 3/4" 3/8" 4 10 20 40 60 100 200 100 90 ' 80 = 70 60 \\ tm W 50 Z ' Z 40 W U W 30 ti 20 ' 10 0 ' 1000.00 100.00 10.00 1.00 0.10 0.01 0.00 GRAIN SIZE IN MILLIMETERS L:ar1_,e7 Fine Coarse Medium Fine Sift Clay ' BOULDERS COBBLES FIN NE ' Exploration Sample Depth Moisture Fines Soil Description f • •-i-i B-1 S-7 13.5' 13% 38% Silty SAND,some gravel • •-•-•-+ B-1 S-15 30.5' 16% 82% Sandy Clayey SILT ' B-2 S-5 16.5' 16% 44% Silty SAND,trace gravel AAA B-2 S-13 28.5' 27% 53% Sandy SILT ' Project: East Kennydale Interceptor OAGRA Work Order: 6-917-10292A ' Earth & Environmental Date: 3-22-96 11335 NE 122nd Way Suite 100 Kirkland, Washington 98034-6918 GRAIN SIZE DISTRIBUTION ' SIZE OF OPENING IN INCHES U.S. STANDARD SIEVE SIZE HYDROMETER 36" 12" 6" 3" 1 1/2" 3/4" 3/8" 4 10 20 40 60 100 200 100 ' 80 \ F- \ 2 70 60 M ' W 50 Z LL ' Z 40 W U W 30 11 20 ' 10 0 1000.00 100.00 10.00 1.00 0.10 0.01 0.00 GRAIN SIZE IN MILLIMETERS Coarse Fine Coarse Medium Fine Silt Clay UQV�QERS g0 BLE FINLGRANED ' Exploration Sample Depth Moisture Fines Soil Description F i B-3 S-10 24.0' 11% 7% Gravelly SAND, some silt • +-�-�-+ B-4 S-14 41.5' 15% 61% Sandy SILT ' B-4 S-19 49.0' 9% 45% Silty SAND,some gravel �� B-5 S-10 24.0' 23% 12% Medium to Fine SAND, some silt ' Project: East Kennydale Interceptor OAGRA Work Order: 6-917-10292A ' Earth & Environmental Date: 3-22-96 11335 NE 122nd Way Suite 100 Kirkland, Washington 98034-6918 GRAIN SIZE DISTRIBUTION ' SIZE OF OPENING IN INCHES U.S. STANDARD SIEVE SIZE HYDROMETER 36" 12" 6" 3" 1 1/2" 3/4" 3/8" 4 10 20 40 60 100 200 100 ' 90 ' 80 F- ' (_'D 70 60 1 W 50 Z U- ' Z 40 W U W 30 d 20 ' 10 0 ' 1000.00 100.00 10.00 1.00 0.10 0.01 0.00 GRAIN SIZE IN MILLIMETERS Coarse Fine Coarse Medium Fine Silt Clay ' BOULDEn gODDLES I GRAVEL IWID FIN RAIN ' Exploration Sample Depth Moisture Fines Soil Description i B-6 S-6 8.5' 26% 12% Medium to Fine SAND,some silt 1 Project: East Kennydale Interceptor OAGRA Work Order: 6-917-10292A Earth & Environmental Date: 3-22-96 11335 N E 122nd Way Suite 100 Kirkland, Washington 98034-6918 i GRAIN SIZE DISTRIBUTION SIZE OF OPENING IN INCHES U.S. STANDARD SIEVE SIZE HYDROMETER 36" 12" 6" 3" 1 1/2" 3/4" 318" 4 10 20 40 60 100 200 100 1 \ 90 = 70 60 } 1 W 50 Z Z 40 1 W 30 a 1 20 1 10 0 1 1000.00 100.00 10.00 1.00 0.10 0.01 0.00 GRAIN SIZE IN MILLIMETERS Coarse Fine Coarse Medium Fine Sift Clay ' OU� 11 QPAVU WD FINEQRANED 1 Exploration Sample Depth Moisture Fines Soil Description B-9 S3 15.0-16.5' 20% 5% Medium to Fine SAND,some silt •�-•-•-+ B-9 S3 22.5-24.0' 25% 4% Medium to Fine SAND,trace sift ' - B-10 S-2 10.0-11.5' 4% 5% Sandy GRAVEL,some silt A ,► * A B-10 S-8 32.5-34.0' 21% 3% Medium to Fine SAND,trace silt ' Project: Kennydale Interceptor OAGRA WorkOrder: 6-91M-10292-B Earth & Environmental ' Date: 11-23-96 11335 NE 122nd Way Suite 100 Kirkland, Washington 98034-6918 1 i 1 1 i 1 1 1 1 1 _ 1 r 1 1 AGRA 1 The Integrated Approach The material used for this report cover and back is made from 100% post consumer PET plastic beverage containers. It was manufactured by AGRA Recycling, a division of AGRA Industries Limited. For professional assistance with your waste management and recycling requirements, contact AGRA Earth & Environmental. NAAnF IN r.ANAnA