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Home My WebLink AboutExh.20_Wall_Stability_1EXHIBIT 20 RECEIVED 07/19/2019 mherrera PLANNING DIVISION DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Bulkhead Wall Stability Addendum Cedar River Apartments ■ Renton, Washington June 10, 2019 ■ Terracon Project No. 81175025 Responsive ■Resourceful ■Reliable 1 EXISTING CONDITIONS Paralleling the Cedar River along the southern boundary of the site exists a concrete block bulkhead wall. The bulkhead wall is understood to have been constructed sometime in the 1980s and was initially built to support ongoing concrete trucking and batch plant operations at that time. The section of bulkhead wall/shoreline studied is an approximate 660-foot section between the eastern end of the settling ponds to the easternmost extent of the property. Along this section, the wall height ranges from 9 to 18 feet with the river at the toe of the outboard face of the wall for most of the length. The wall is constructed of stacked concrete blocks with individual block dimensions of 3-foot by 3-foot by 6-foot. The blocks are stacked vertical for three to four blocks, based on observation of the exposed portions of the wall. A visual characterization of the wall suggests that the material at the toe of the wall is mass concrete that was apparently wasted along the shoreline of the Cedar River prior to construction of the wall. The mass concrete is clearly visible from the top of the wall and appears to span the entire wall length and for at least a depth common with the bottom of the river. The wall appears to be founded on the mass concrete with base blocks likely embedded in the concrete. The wall appears to be maintaining a near-vertical to slight batter away from the river. Evidence of wall distress such as bulging, tilting, or gapping between concrete blocks was not observed at any portion of the wall which suggests that the wall has not experienced movement since initial construction. Materials retained by the wall and foundation materials at the wall base were studied through subsurface explorations consisting of test pits and soil borings. A total of three test pits and four soil borings at three areas along the wall alignment were completed to facilitate the stability analyses. The results of the subsurface explorations are summarized section below. Cross sections of the wall and retained soils at the three areas studied are presented in the attached figures at the end of this addendum. SUBSURFACE CONDITIONS Work performed previously in the vicinity of the bulkhead wall identified that subsurface conditions generally consisted of loose to dense sandy and gravelly alluvial soils to about 37 ½ feet at which the soils transition to dense to very dense gravels. A zone of potentially liquefiable soil was previously identified, but spatially, the liquefaction hazard is not believed to be site-wide. The initial geotechnical investigation did not explore subsurface conditions along the portion of the shoreline that is east of the settling ponds; therefore, the current subsurface explorations were focused on characterizing both materials retained behind the wall and the extent of the liquefaction hazard, if present. DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Bulkhead Wall Stability Report Cedar River Apartments ■ Renton, Washington June 10, 2019 ■ Terracon Project No. 81175025 Responsive ■Resourceful ■Reliable 2 Explorations performed immediately behind the wall consisted of three test pits up to 9 feet below the ground surface (bgs) and one shallow soil boring to 15 feet bgs. To investigate the extent of the liquefaction hazard, three soil borings were advanced to depth of at least 50 feet. The exploration locations for this study are presented on the exploration site plan attached at the end of this addendum. The subsurface conditions observed in the soil borings were generally consistent with those presented in the geotechnical engineering report. Boring B-3-19 was performed nearest to the settling ponds and exhibited a zone of potentially liquefiable soils between 22 ½ and 37 ½ feet bgs. This boring agrees well with boring B-5 performed as part of the initial geotechnical investigation which also identified liquefiable soils. Borings B-1-19 and B-2-19 suggest that soils are denser to the east and that a liquefaction hazard is not present for this portion of the site. Further discussion of liquefaction is presented in a later section. Both B-3-19 and B-5 are in the general vicinity of the settling ponds; therefore, the liquefaction hazard is assumed to exist only for the portion of the wall nearest to the settling ponds. Test pit explorations performed behind the block wall encountered multiple layers of mass concrete and course granular fill. At test pit locations TP-1-19 and TP-2-19, test pits were refused at 4 and 6 feet, respectively, due to the presence of higher strength mass concrete. Advancement through shallower layers of mass concrete to the base of the wall was accomplished at TP-3-19; however, refusal from mass concrete occurred at an elevation consistent with the base of the block wall. It was observed in this test pit that the concrete blocks comprising the bulkhead wall are placed on a layer of mass concrete. The thickness of the concrete on which the blocks are stacked is estimated to be ¾-foot thick at the area investigated near the settling ponds. The boreholes were observed while drilling for the presence and level of groundwater. The water levels observed in the boreholes ranged from 10 to 20 feet which is generally consistent with groundwater information presented previously in the geotechnical engineering report. LIQUEFACTION Liquefaction is the phenomenon where saturated soils develop high pore water pressures during seismic shaking and lose their strength characteristics. This phenomenon generally occurs in areas of high seismicity, where groundwater is shallow and loose granular soils or relatively non- plastic fine-grained soils are present. These conditions were observed in soil boring B-3-19 but do not appear to be present at locations B-1-19 and B-2-19. Previous evaluations of liquefaction performed at the site were code-based and were performed in support the building design. However, the section of shoreline studied is sufficiently far from any proposed structures and a risk to life safety is not readily present. Therefore, use of a code-based seismic design event for liquefaction evaluation of the existing bulkhead is not applicable as larger, more rare events are assumed. We believe a more appropriate evaluation is to assess smaller, more frequently occurring earthquakes DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Bulkhead Wall Stability Report Cedar River Apartments ■ Renton, Washington June 10, 2019 ■ Terracon Project No. 81175025 Responsive ■Resourceful ■Reliable 3 to assess if stabilization measures of the shoreline/bulkhead wall system are necessary. Based on our understanding of other evaluations of existing shorelines performed within King County, we have assumed a seismic event with a 100-year return period. Liquefaction triggering was evaluated using WSLiq software developed by Prof. Steven L. Kramer at the University of Washington (http://faculty.washington.edu/kramer/WSliq/WSliq.htm). Based on the results of the evaluation, it is most likely that liquefaction will occur between 22 ½ and 37 ½ feet bgs within the general vicinity of B-3-19. For soils east of this location, liquefaction is not expected to trigger. Although we estimate up to 6 inches of liquefaction-induced settlement of the ground surface behind the bulkhead wall, the issue of settlement is more a matter of usability for site operations and that any inconvenience presented by ground subsidence will be address through regular maintenance. The zone where liquefaction trigger is expected will be modeled in our stability evaluations with a reduced shear strength to reflect the liquefied condition. WALL STABILITY EVALUATIONS Development of Bulkhead Wall Cross Sections To support the stability evaluations of the bulkhead wall, three cross sections were developed based on visual observations of the bulkhead wall and findings from the test pit and soil borings explorations. Test pits and soil borings were co-located to facilitate development of cross sections to be used for stability evaluations. General discussion of test pit and soil boring explorations as well as sampling and field characterization of soils are presented in Appendix A of the geotechnical engineering report. The explorations performed as part of the bulkhead wall investigation were performed in general accordance with this discussion. At all exploration locations, mass concrete was encountered. For the test pits, the presence and strength of the mass concrete refused advancement attempts of a rather large excavator (CAT 320C). Test pits TP-1-19 and T-2-19 were reattempted at several locations within the general vicinity of the originally proposed exploration location but advancement was refused by the presence mass concrete for each attempt. Additionally, advancement of hollow-stem augers were initially refused in B-1-19 despite several attempts to relocate the boring. To obtain subsurface data at TP-2-19 and B-1-19, a sonic core rig was mobilized to penetrate the mass concrete. Sonic coring returns a continues sample of material cored while permitting standard penetration testing (SPT) in regular 5-foot intervals. Based on the observations of the excavator and drill rig attempts to fracture and break through the mass concrete, and efforts of the sonic core rig to penetrate the concrete, it was concluded that the concrete is intact, wide-spread, and of high strength. The cross sections developed are described below as well as presented graphically in the attached figures at the end of this addendum. DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Bulkhead Wall Stability Report Cedar River Apartments ■ Renton, Washington June 10, 2019 ■ Terracon Project No. 81175025 Responsive ■Resourceful ■Reliable 4 Cross Section General Location Explorations Approx. Observed Wall Height (ft)1 Approx. River Depth at Toe of Wall/Slope (ft) Cumulative Thickness of Mass Concrete 2 A-A’ West end of shoreline section studied, nearest to the settling ponds TP-3-19 B-3-19 9 4 1 ¾ B-B’ Approximate midpoint between settling ponds and east end of site TP-2-19 B-2-19 B-4-19 14 3 14 4,5 C-C’East end of site TP-1-19 B-1-19 18 3 2 > 13 4,6 1.Exposed height of the wall. Based on visual observation from the portion of wall visible from the top of wall. Includes mass concrete that is present at the face of the wall. 2.Estimated thickness is based on test pit and soil boring results performed behind the wall. 3.Exposed height is largely mass concrete with concrete blocks fully embedded. Mass concrete is observed to the river bottom. 4.Cumulative thickness is based on recovery from sonic core drilling. 5.The approximate bottom 5 feet of the wall height is observed to be mass concrete. 6.Evidence of concrete observed as deep as 24 ½ feet bgs. Soil Parameter Derivation and Global Stability Methodology An assessment of concrete strength and quality was not performed. Based on observations during advancement of the subsurface explorations, the mass concrete encountered is assumed to have a strength and quality no worse than that of lean mix concrete. Fresh lean mix concrete typically exhibits an unconfined compressive strength of at least 500 psi. To account for aging of the concrete and the slope stability failure mode being consistent with shear than compression, we assume reduction factors of 0.5 and 0.1, respectively. Therefore, a shear strength of 25 psi was applied to the mass concrete. Strength parameters for the soil units observed were derived from SPT results using published correlations. For a post-liquefaction scenario, a residual shear strength of the liquefied soils in section A-A’ assumes the methodology proposed by Olson and Stark 2002 for deriving a post- liquefaction residual shear strength. The unit weight and strength parameters for each soil unit, including mass concrete, is presented on the attached figures presented at the end of this memorandum. Stability evaluations were performed using Rocscience SLIDE 6.0 software. The method of analysis for predicting potential slip surfaces used Spencer’s method (1967). Slip surfaces were DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Bulkhead Wall Stability Report Cedar River Apartments ■ Renton, Washington June 10, 2019 ■ Terracon Project No. 81175025 Responsive ■Resourceful ■Reliable 5 limited to those that initiate behind the wall and daylight through the river bed at the toe of the slope. Internal wall stability will be evaluated by others. The outputs from the slope stability software are presented at the end of this memorandum. For each cross section previously presented, slope stability analyses were performed for the following scenarios for the existing condition of the wall: ■Static – assumes a nominal live-load of 250 psf uniformly distributed along the back of the wall and a high-water river event, which is assumed to be 5 feet above the height the stage observed at the time of drilling. ■Seismic – assumes a 100-year return period for the wall/shoreline system and an average river condition. For the horizontal acceleration, one-half of the peak ground acceleration is assumed. For all section, the soils are assumed to not liquefy for this scenario. ■Post-liquefaction – for section A-A’, the soils between 22 ½ and 37 ½ feet bgs are assumed to liquefy and mobilize a residual shear strength. Triggering of liquefaction is not expected to occur for sections B-B’ and C-C’. The analyses performed do not consider scour at the base of the wall. Further assessment of the wall condition, particularly the extent of mass concrete at the base of the wall, is necessary to evaluate scour potential. We understand scour is being evaluated by others but have assumed scour potential will be minimal due to the presence of the mass concrete. Global Stability Evaluation Results The results of the slope stability analyses for static, seismic, and post-liquefaction scenarios are presented in the table below: Cross Section Static 1 Seismic 1,2 Post-Liquefaction 1 A-A’1.93 1.34 1.03 B-B’3.15 2.03 ---3 C-C’2.90 1.87 ---3 1.Factors of safety presented are global minimums and do not consider shallow, surficial failures that may occur in front of the wall. 2.Horizontal acceleration value of 0.17 was assumed (i.e. PGA of 0.17 for 100-year return period). 3.Liquefaction is not expected to trigger at this location DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Bulkhead Wall Stability Report Cedar River Apartments ■ Renton, Washington June 10, 2019 ■ Terracon Project No. 81175025 Responsive ■Resourceful ■Reliable 6 Typical minimum target factors of safety for static and seismic stability of existing shorelines are assumed to be 1.3 and 1.0, respectively. Although a factor of safety less than 1.0 is undesired, the result does not imply a collapse of the bulkhead wall but rather some movement should be expected. As observed in the table above, the factor of safeties are greater than 1.0 therefore only negligible wall movements are expected for a 100-year return period. In our opinion, the bulkhead wall as currently constructed is not at risk of a global stability failure. In the event of a larger, more rare-event earthquake, it is likely that some wall movements will occur. It is recommended that following an earthquake event in excess of a 100- yr return period, a post-earthquake reconnaissance should be performed to assess any damage incurred by the wall. To support internal stability evaluations to be performed by a structural engineer, recommendations for lateral earth pressures and base sliding of the concrete blocks are providing in the following section. RECOMMENDATIONS FOR STUCTURAL EVALUATIONS Lateral Earth Pressures The existing bulkhead wall appears to consist of stacked concrete block resting statically on mass concrete. Materials retained by the bulkhead wall consist of course granular fill and mass concrete. For static conditions, the strength of the mass concrete is high enough that an earth pressure is not expected developed on the wall. Therefore, the recommended earth pressures presented below, are based on granular fill where observed in the explorations behind the wall. For seismic earth pressures, a uniformly distributed pressure for the full wall height is assumed to have developed. Lateral Earth Pressure Design Parameters Section Active Equivalent Fluid Pressure 1 Seismic Increment 3 A-A’(25)H (3)H B-B’(12)H (3)H C-C’(17)H (3)H 1.Based on an active earth pressure coefficient, Ka, of 0.31 and a soil unit weight of 125 pcf. 2.Depth intervals represent zones where mass concrete was observed. 3.Values are in addition to static earth pressures and should be applied as a uniform pressure for the full wall height. 4.The approximate bottom 5 feet of the wall height is observed to be mass concrete. 5.Exposed height is largely mass concrete with concrete blocks fully embedded. Mass concrete is observed to the river bottom. DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Bulkhead Wall Stability Report Cedar River Apartments ■ Renton, Washington June 10, 2019 ■ Terracon Project No. 81175025 Responsive ■Resourceful ■Reliable 7 Concrete Block Sliding At the depths encountered during the test pit explorations, it was observed that the mass concrete exhibits a rough surface. This is likely due to placement without control or screeding/leveling; therefore, the interface friction angle with the base of the concrete blocks will likely be similar to that of soil. We recommend assuming an ultimate interface coefficient of 0.42 for stability evaluation of block sliding. For interface friction between concrete blocks, a published value typical for concrete sliding on concrete appears appropriate as the contact between blocks appears to free of interlocking features. STABILIZATION ALTERNATIVES Based on the analyses performed and the assumed earthquake return period of 100-yrs, we believe the bulkhead wall, in the current condition, is not at risk of a global stability failure. Pending the findings of the structural evaluation of the bulkhead wall internal stability, the wall may require a retrofit to provide long-term stability. Potential stabilization solutions include the following: ■Mechanically stabilized earth wall (MSEW) – an MSEW wall consists of interlayered geotextile and compacted structural fill to create a composite system capable of being constructed at vertical slopes. The earth pressure could be alleviated from the concrete block wall by wrapping the end of soil layers with the geotextile. This form of construction is common for roadway applications. The concrete block wall would then serve as a facing to protect the MSEW portion of the wall. The void space between the MSEW and the concrete blocks could be filled with free-draining granular fill which would also promote drainage. Design parameters for design of the MSEW can be provided at a later date should a retrofit solution be deemed necessary. ■Gabion basket wall – this wall type is a form of gravity wall and is common for bridge abutments and river applications. The wall is constructed by placing quarry-spall sized rocks in welded-wire baskets and stacking the baskets to the desired height. These could be installed behind the existing concrete wall to alleviate the earth pressure on the block wall from the retained soil. The gabion baskets would also promote drainage for the bulkhead/shoreline system. Although larger earthquake events may occur in the Puget Sound region, these events are extremely rare. Should a larger earthquake event occur near the site, Terracon should be retained to provide a site reconnaissance to review the condition of the wall following the event. Following the reconnaissance and assessment of the wall, if excessive displacement/damage is observed Terracon could develop options for repair of the bulkhead. DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Bulkhead Wall Stability Report Cedar River Apartments ■ Renton, Washington June 10, 2019 ■ Terracon Project No. 81175025 Responsive ■Resourceful ■Reliable 8 GENERAL COMMENTS Our analysis and opinions are based upon our understanding of the project, the geotechnical conditions in the area, and the data obtained from our site exploration. Natural variations will occur between exploration point locations or due to the modifying effects of construction or weather. The nature and extent of such variations may not become evident until during or after construction. Terracon should be retained as the Geotechnical Engineer for further evaluations. Our Scope of Services does not include either specifically or by implication any environmental or biological (e.g., mold, fungi, bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, other studies should be undertaken. Our services and any correspondence or collaboration are intended for the sole benefit and exclusive use of our client for specific application to the project discussed and are accomplished in accordance with generally accepted geotechnical engineering practices with no third-party beneficiaries intended. Any third-party access to services or correspondence is solely for information purposes to support the services provided by Terracon to our client. Reliance upon the services and any work product is limited to our client and is not intended for third parties. Any use or reliance of the provided information by third parties is done solely at their own risk. No warranties, either express or implied, are intended or made. Site characteristics as provided are for design purposes and not to estimate construction costs. Any use of our report in that regard is done at the sole risk of the cost estimator as there may be variations on the site that are not apparent in the data that could significantly impact construction cost. Any parties charged with estimating construction costs should seek their own site characterization for specific purposes to obtain the specific level of detail necessary for costing. Site safety, and cost estimating including, excavation support, and dewatering requirements/design are the responsibility of others. If changes in the nature, design, or location of the project are planned, our conclusions and recommendations shall not be considered valid unless we review the changes and either verify or modify our conclusions in writing. DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Responsive ■Resourceful ■Reliable FIGURES DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 1.931.93 W 1.931.93 Material Name Color Unit Weight (lbs/Ō3) Cohesion (psf) Phi (deg) FILL 120 0 32 Loose to Med. Dense Sand 125 0 32 Dense Sand 125 0 38 Dense Gravel 130 0 42 Blocks 135 Concrete 145 36008060 4020060 80 100 120 140 160 180 200 220 1 Figure No. 81175025 Project No. Section A-A' - Static ConditionCedar River Apartment Bulkhead Wall Stability SLIDEINTERPRET 6.038 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 3.153.15 W 3.153.15 Material Name Color Unit Weight (lbs/Ō3) Cohesion (psf) Phi (deg) Dense Gravel 130 0 42 FILL 120 0 32 Dense Sand 125 0 38 Concrete 145 3600 Block 1351008060 402000 20 40 60 80 100 120 140 160 2 Figure No. 81175025 Project No. Section B-B' Static ConditionCedar River Apartment Bulkhead Wall Stability SLIDEINTERPRET 6.038 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 2.902.90 W 2.902.90 Material Name Color Unit Weight (lbs/Ō3) Cohesion (psf) Phi (deg) Concrete 145 3600 Fill 125 0 32 Dense Sand 125 0 38 Gravel 130 0 42 Blocks 1351201008060 40200-20 0 20 40 60 80 100 120 140 160 6 Figure No. 81175025 Project No. Section C-C' Static ConditionCedar River Apartment Bulkhead Wall Stability SLIDEINTERPRET 6.038 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Responsive ■Resourceful ■Reliable SITE EXPLORATION PLAN DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 SITE EXPLORATION PLAN Cedar River Apartments ■ Renton, Washington June 10, 2019 ■ Terracon Project No. 81175025 Note to Preparer: This is a large table with outside borders. 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MAP 2 LANDSCAPE DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES MAP PROVIDED BY MICROSOFT BING MAPS DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 EXPLORATION RESULTS DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 4.0 8.5 11.0 14.0 19.0 20.0 21.0 21.5 24.5 25.0 41 36.5 34 31 26 25 24 23.5 20.5 20 50/4" 50/1" 38-50/4" N = 50/4" 10-40-26 N=66 14-12-11 N=23 4 1 10 18 9 S-1 S-2 S-3 S-4 S-5 13 4 6 16 SANDY GRAVEL (GW), brownish gray to brown, damp, very dense, (FILL) CONCRETE, light gray SAND WITH SILT (SP-SM), abundant cobbles, brown, damp, very dense, (FILL) CONCRETE, light gray SILTY GRAVEL (GW-GM), with sand, brown, moist to wet, very dense, some woody debris, (FILL) CONCRETE, light gray SAND (SP), trace silt, brown, wet, very dense, (FILL) CONCRETE, light gray SAND WITH GRAVEL (SP), trace silt, brown, wet, very dense, (FILL) CONCRETE, light gray SAND WITH GRAVEL (SP), trace silt, brown, wet, medium dense to very dense Hammer Type: Automatic (ETR = 96%)Stratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 81175025 CEDAR RIVER UPDATED - LAB COPY.GPJ MODELLAYER.GPJ 5/30/19DEPTH Surface Elev.: 45 (Ft.) ELEVATION (Ft.) Page 1 of 2 Advancement Method: Sonic Abandonment Method: 21905 64th Ave W, Ste 100 Mountlake Terrace, WA Notes: Project No.: 81175025 Drill Rig: Geoprobe 8140LC BORING LOG NO. B-1-19 SRMRenton, LLCCLIENT: Spokane, WA Driller: Holocene Boring Completed: 05-15-2019 PROJECT: Cedar River Apartments Elevations were interpolated from a topographic site plan. See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any). See Supporting Information for explanation of symbols and abbreviations. 1915 Maple Valley Highway Renton, WA SITE: Boring Started: 05-15-2019 While drilling WATER LEVEL OBSERVATIONS WATER LEVELOBSERVATIONSDEPTH (Ft.)5 10 15 20 25 30 FIELD TESTRESULTSRECOVERY (In.)SAMPLENUMBERPERCENT FINESWATERCONTENT (%)See Exploration PlanLOCATION Latitude: 47.479469° Longitude: -122.191601°GRAPHIC LOGSAMPLE TYPEDocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 39.0 51.5 6 -6.5 13-26-40 N=66 7-33-50/5" N = 83/11" 22-33-26 N=59 10-28-50/6" N = 78/12" 15-13-18 N=31 15 14 12 18 14 S-6 S-7 S-8 S-9 S-10 216SAND WITH GRAVEL (SP), trace silt, brown, wet, medium dense to very dense (continued) GRAVEL WITH SAND (GW), brown, wet, very dense at S-10, rock fragments in shoe, likely overstated blow-count Boring Terminated at 51.5 Feet Hammer Type: Automatic (ETR = 96%)Stratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 81175025 CEDAR RIVER UPDATED - LAB COPY.GPJ MODELLAYER.GPJ 5/30/19DEPTH Surface Elev.: 45 (Ft.) ELEVATION (Ft.) Page 2 of 2 Advancement Method: Sonic Abandonment Method: 21905 64th Ave W, Ste 100 Mountlake Terrace, WA Notes: Project No.: 81175025 Drill Rig: Geoprobe 8140LC BORING LOG NO. B-1-19 SRMRenton, LLCCLIENT: Spokane, WA Driller: Holocene Boring Completed: 05-15-2019 PROJECT: Cedar River Apartments Elevations were interpolated from a topographic site plan. See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any). See Supporting Information for explanation of symbols and abbreviations. 1915 Maple Valley Highway Renton, WA SITE: Boring Started: 05-15-2019 While drilling WATER LEVEL OBSERVATIONS WATER LEVELOBSERVATIONSDEPTH (Ft.)35 40 45 50 FIELD TESTRESULTSRECOVERY (In.)SAMPLENUMBERPERCENT FINESWATERCONTENT (%)See Exploration PlanLOCATION Latitude: 47.479469° Longitude: -122.191601°GRAPHIC LOGSAMPLE TYPEDocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 1.0 3.0 6.0 6.5 11.0 20.5 45 43 40 39.5 35 25.5 7-8-50/2" 5-4-23 N=27 3-7-22 N=29 6-13-18 N=31 8-13-13 N=26 25-22-22 N=44 8 14 12 6 6 8 S-1 S-2 S-3 S-4 S-5 S-6 815 SILTY SAND WITH GRAVEL (SM), fine to medium grained, light gray to brown, damp, (medium dense), (FILL) CONCRETE, light gray SILTY SAND WITH GRAVEL (SM), fine to medium grained, light brown to brown, moist, loose to medium dense, (FILL) CONCRETE, light gray SILTY SAND WITH GRAVEL (SM), fine to medium grained, light brown to brown, moist, loose to medium dense SAND WITH GRAVEL (SP), trace fines, medium to coarse grained, gray to orangish brown, moist, medium dense, interbedded thin silty sand lenses GRAVEL WITH SILT AND SAND (GW-GM), cobbles and boulders, medium to coarse grained, dark gray to olive brown, wet, dense to very dense, difficult drilling due to presence of cobbles and boulders Hammer Type: Automatic (ETR = 86%)Stratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 81175025 CEDAR RIVER UPDATED - LAB COPY.GPJ MODELLAYER.GPJ 5/30/19DEPTH Surface Elev.: 46 (Ft.) ELEVATION (Ft.) Page 1 of 2 Advancement Method: Hollow Stem Auger Abandonment Method: Backfilled with Auger Cuttings and/or Bentonite 21905 64th Ave W, Ste 100 Mountlake Terrace, WA Notes: Project No.: 81175025 Drill Rig: D-90 BORING LOG NO. B-2-19 SRMRenton, LLCCLIENT: Spokane, WA Driller: Holocene Boring Completed: 05-02-2019 PROJECT: Cedar River Apartments Elevations were interpolated from a topographic site plan. See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any). See Supporting Information for explanation of symbols and abbreviations. 1915 Maple Valley Highway Renton, WA SITE: Boring Started: 05-02-2019 Inferred from sample moisture change WATER LEVEL OBSERVATIONS WATER LEVELOBSERVATIONSDEPTH (Ft.)5 10 15 20 25 30 FIELD TESTRESULTSRECOVERY (In.)SAMPLENUMBERPERCENT FINESWATERCONTENT (%)See Exploration PlanLOCATION Latitude: 47.479585° Longitude: -122.192289°GRAPHIC LOGSAMPLE TYPEDocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 50.9 -5 14-36-38 N=74 50/2" 29-30-22 N=52 50/5" 18-50/5" 14 2 2 3 0 S-7 S-8 S-9 S-10 S-11 712GRAVEL WITH SILT AND SAND (GW-GM), cobbles and boulders, medium to coarse grained, dark gray to olive brown, wet, dense to very dense, difficult drilling due to presence of cobbles and boulders (continued) Boring Terminated at 50.9 Feet Hammer Type: Automatic (ETR = 86%)Stratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 81175025 CEDAR RIVER UPDATED - LAB COPY.GPJ MODELLAYER.GPJ 5/30/19DEPTH Surface Elev.: 46 (Ft.) ELEVATION (Ft.) Page 2 of 2 Advancement Method: Hollow Stem Auger Abandonment Method: Backfilled with Auger Cuttings and/or Bentonite 21905 64th Ave W, Ste 100 Mountlake Terrace, WA Notes: Project No.: 81175025 Drill Rig: D-90 BORING LOG NO. B-2-19 SRMRenton, LLCCLIENT: Spokane, WA Driller: Holocene Boring Completed: 05-02-2019 PROJECT: Cedar River Apartments Elevations were interpolated from a topographic site plan. See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any). See Supporting Information for explanation of symbols and abbreviations. 1915 Maple Valley Highway Renton, WA SITE: Boring Started: 05-02-2019 Inferred from sample moisture change WATER LEVEL OBSERVATIONS WATER LEVELOBSERVATIONSDEPTH (Ft.)35 40 45 50 FIELD TESTRESULTSRECOVERY (In.)SAMPLENUMBERPERCENT FINESWATERCONTENT (%)See Exploration PlanLOCATION Latitude: 47.479585° Longitude: -122.192289°GRAPHIC LOGSAMPLE TYPEDocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 5.5 8.0 15.0 37.5 35 28 14-50/2" 2-4-4 N=8 1-5-8 N=13 4-8-7 N=15 3-4-2 N=6 7 10 6 7 0 S-1 S-2 S-3 S-4 S-5 8 2 32 25 SILTY SAND (SM), medium to coarse grained, light gray to tan, moist, medium dense, (FILL) CONCRETE, light gray SAND WITH SILT (SP-SM), medium to coarse grained, light gray to tan, moist to wet, loose to medium dense SAND (SP), trace gravel, fine to medium grained, gray brown to brown, wet, loose medium dense Hammer Type: Automatic (ETR = 86%)Stratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 81175025 CEDAR RIVER UPDATED - LAB COPY.GPJ MODELLAYER.GPJ 5/30/19DEPTH Surface Elev.: 43 (Ft.) ELEVATION (Ft.) Page 1 of 2 Advancement Method: Hollow Stem Auger Abandonment Method: Backfilled with Auger Cuttings and/or Bentonite 21905 64th Ave W, Ste 100 Mountlake Terrace, WA Notes: Project No.: 81175025 Drill Rig: D-90 BORING LOG NO. B-3-19 SRMRenton, LLCCLIENT: Spokane, WA Driller: Holocene Boring Completed: 05-02-2019 PROJECT: Cedar River Apartments Elevations were interpolated from a topographic site plan. See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any). See Supporting Information for explanation of symbols and abbreviations. 1915 Maple Valley Highway Renton, WA SITE: Boring Started: 05-02-2019 While drilling WATER LEVEL OBSERVATIONS WATER LEVELOBSERVATIONSDEPTH (Ft.)5 10 15 20 25 30 FIELD TESTRESULTSRECOVERY (In.)SAMPLENUMBERPERCENT FINESWATERCONTENT (%)See Exploration PlanLOCATION Latitude: 47.479772° Longitude: -122.193455°GRAPHIC LOGSAMPLE TYPEDocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 41.5 56.5 1.5 -13.5 4-3-1 N=4 2-1-4 N=5 4-7-37 N=44 27-11-16 N=27 25-19-34 N=53 18-23-39 N=62 8 12 6 3 2 8 S-6 S-7 S-8 S-9 S-10 S-11 5 3 0 35 25 7 SAND (SP), trace gravel, fine to medium grained, gray brown to brown, wet, loose medium dense (continued) GRAVEL WITH SAND (GW), fine to coarse grained, dark gray to dark olive brown, wet, dense to very dense Boring Terminated at 56.5 Feet Hammer Type: Automatic (ETR = 86%)Stratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 81175025 CEDAR RIVER UPDATED - LAB COPY.GPJ MODELLAYER.GPJ 5/30/19DEPTH Surface Elev.: 43 (Ft.) ELEVATION (Ft.) Page 2 of 2 Advancement Method: Hollow Stem Auger Abandonment Method: Backfilled with Auger Cuttings and/or Bentonite 21905 64th Ave W, Ste 100 Mountlake Terrace, WA Notes: Project No.: 81175025 Drill Rig: D-90 BORING LOG NO. B-3-19 SRMRenton, LLCCLIENT: Spokane, WA Driller: Holocene Boring Completed: 05-02-2019 PROJECT: Cedar River Apartments Elevations were interpolated from a topographic site plan. See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any). See Supporting Information for explanation of symbols and abbreviations. 1915 Maple Valley Highway Renton, WA SITE: Boring Started: 05-02-2019 While drilling WATER LEVEL OBSERVATIONS WATER LEVELOBSERVATIONSDEPTH (Ft.)35 40 45 50 55 FIELD TESTRESULTSRECOVERY (In.)SAMPLENUMBERPERCENT FINESWATERCONTENT (%)See Exploration PlanLOCATION Latitude: 47.479772° Longitude: -122.193455°GRAPHIC LOGSAMPLE TYPEDocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 8.5 14.5 15.0 32.5 26.5 26 42 30 60 S-1 S-2 S-3 GRAVEL WITH SILT AND SAND (GW-GM), brown, damp, (FILL) CONCRETE, light gray SAND WITH GRAVEL (SP), trace fines, medium to coarse grained, gray to brown, moist Boring Terminated at 15 Feet Hammer Type: Automatic (ETR = 96%)Stratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 81175025 CEDAR RIVER UPDATED - LAB COPY.GPJ MODELLAYER.GPJ 5/30/19DEPTH Surface Elev.: 41 (Ft.) ELEVATION (Ft.) Page 1 of 1 Advancement Method: Sonic Abandonment Method: 21905 64th Ave W, Ste 100 Mountlake Terrace, WA Notes: Project No.: 81175025 Drill Rig: Geoprobe 8140LC BORING LOG NO. B-4-19 SRMRenton, LLCCLIENT: Spokane, WA Driller: Holocene Boring Completed: 05-15-2019 PROJECT: Cedar River Apartments Elevations were interpolated from a topographic site plan. See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any). See Supporting Information for explanation of symbols and abbreviations. 1915 Maple Valley Highway Renton, WA SITE: Boring Started: 05-15-2019WATER LEVEL OBSERVATIONS Groundwater not encountered WATER LEVELOBSERVATIONSDEPTH (Ft.)5 10 15 FIELD TESTRESULTSRECOVERY (In.)SAMPLENUMBERPERCENT FINESWATERCONTENT (%)See Exploration PlanLOCATION Latitude: 47.479537° Longitude: -122.192378°GRAPHIC LOGSAMPLE TYPEDocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 4.0 45+/- location reattempted at several locations but refused by mass concrete at each SAND WITH SILT AND GRAVEL (SP-SM), trace cobbles, medium to coarse grained, brown to yellow-brown, (loose), damp, (FILL) @ 4 ft, mass concrete, unable to excavate through Refusal due to concrete at 4 Feet Stratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 81175025 CEDAR RIVER APART - TESTPITS.GPJ MODELLAYER.GPJ 5/30/19DEPTH Approximate Surface Elev.: 49.0 (Ft.) +/- ELEVATION (Ft.) Page 1 of 1 Advancement Method: Excavation Abandonment Method: Backfill with excavation spoils 21905 64th Ave W, Ste 100 Mountlake Terrace, WA Notes: Project No.: 81175025 Excavator: CAT 320 TEST PIT LOG NO. TP-1-19 SRMRenton, LLCCLIENT: Spokane, WA Operator: GM Test Pit Completed: 05-01-2019 PROJECT: Cedar River Apartments Elevations were interpolated from a topographic site plan. See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any). See Supporting Information for explanation of symbols and abbreviations. 1915 Maple Valley Highway Renton, WA SITE: Test Pit Started: 05-01-2019WATER LEVEL OBSERVATIONS Groundwater not encountered during excavation WATER LEVELOBSERVATIONSDEPTH (Ft.)FIELD TESTRESULTSSee Exploration PlanLOCATION Latitude: 47.479302° Longitude: -122.191377°GRAPHIC LOGSAMPLE TYPEDocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 6.0 39+/- test pit reattempted approximately 30 ft back from retaining wall and was again refused by mass concrete SAND WITH SILT AND GRAVEL (SP-SM), trace cobbles, medium to coarse grained, brown to yellow-brown, (loose), damp, (FILL) @ 6 ft, mass concrete, unable to excavate through Refusal due to concrete at 6 Feet Stratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 81175025 CEDAR RIVER APART - TESTPITS.GPJ MODELLAYER.GPJ 5/30/19DEPTH Approximate Surface Elev.: 45.0 (Ft.) +/- ELEVATION (Ft.) Page 1 of 1 Advancement Method: Excavation Abandonment Method: Backfill with excavation spoils 21905 64th Ave W, Ste 100 Mountlake Terrace, WA Notes: Project No.: 81175025 Excavator: CAT 320 TEST PIT LOG NO. TP-2-19 SRMRenton, LLCCLIENT: Spokane, WA Operator: GM Test Pit Completed: 05-01-2019 PROJECT: Cedar River Apartments Elevations were interpolated from a topographic site plan. See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any). See Supporting Information for explanation of symbols and abbreviations. 1915 Maple Valley Highway Renton, WA SITE: Test Pit Started: 05-01-2019WATER LEVEL OBSERVATIONS Groundwater not encountered during excavation WATER LEVELOBSERVATIONSDEPTH (Ft.)5 FIELD TESTRESULTSSee Exploration PlanLOCATION Latitude: 47.479571° Longitude: -122.192532°GRAPHIC LOGSAMPLE TYPEDocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 6.0 6.5 7.0 7.5 8.2 9.0 36.5+/- 36+/- 35.5+/- 35+/- 34.5+/- 33.5+/- SAND WITH GRAVEL (SP), trace cobbles, medium to coarse grained, brown to yellow-brown, (loose), damp, (FILL) CONCRETE SILTY SAND WITH GRAVEL (SM), fine to coarse grained, brown, (loose), damp, (FILL) CONCRETE SILTY SAND WITH GRAVEL (SM), fine to coarse grained, brown, (loose), damp, (FILL) CONCRETE, bottom of block wall at 9 ft, concrete at base of retaining wall, unable to excavate through concrete beyond 9 ft Refusal due to concrete at 9 Feet Stratification lines are approximate. In-situ, the transition may be gradual.THIS BORING LOG IS NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GEO SMART LOG-NO WELL 81175025 CEDAR RIVER APART - TESTPITS.GPJ MODELLAYER.GPJ 5/30/19DEPTH Approximate Surface Elev.: 42.5 (Ft.) +/- ELEVATION (Ft.) Page 1 of 1 Advancement Method: Excavation Abandonment Method: Backfill with excavation spoils 21905 64th Ave W, Ste 100 Mountlake Terrace, WA Notes: Project No.: 81175025 Excavator: CAT 320 TEST PIT LOG NO. TP-3-19 SRMRenton, LLCCLIENT: Spokane, WA Operator: GM Test Pit Completed: 05-01-2019 PROJECT: Cedar River Apartments Elevations were interpolated from a topographic site plan. See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any). See Supporting Information for explanation of symbols and abbreviations. 1915 Maple Valley Highway Renton, WA SITE: Test Pit Started: 05-01-2019WATER LEVEL OBSERVATIONS Groundwater not encountered during excavation WATER LEVELOBSERVATIONSDEPTH (Ft.)5 FIELD TESTRESULTSSee Exploration PlanLOCATION Latitude: 47.479715° Longitude: -122.193637°GRAPHIC LOGSAMPLE TYPEDocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0.0010.010.1110100 30 40 501.5 200681014413/4 1/2 60 GRAIN SIZE IN MILLIMETERSPERCENT FINER BY WEIGHTHYDROMETERU.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS 4 3/8 3 100 14032 GRAIN SIZE DISTRIBUTION ASTM D422 / ASTM C136 6 16 20 PROJECT NUMBER: 81175025 SITE: 1915 Maple Valley Highway Renton, WA PROJECT: Cedar River Apartments CLIENT: SRMRenton, LLC Spokane, WA 21905 64th Ave W, Ste 100 Mountlake Terrace, WA LABORATORY TESTS ARE NOT VALID IF SEPARATED FROM ORIGINAL REPORT. GRAIN SIZE: USCS-2 81175025 CEDAR RIVER UPDATED - LAB COPY.GPJ TERRACON_DATATEMPLATE.GDT 5/30/19medium B-1-19 B-1-19 B-2-19 B-3-19 coarse coarsefine fineCOBBLESGRAVELSAND SILT OR CLAY POORLY GRADED SAND with GRAVEL (SP) POORLY GRADED SAND with GRAVEL (SP) POORLY GRADED SAND with SILT and GRAVEL (SP-SM) WELL-GRADED GRAVEL with SAND (GW) 4.0 2.0 7.8 0.4 16 16 15 7 B-1-19 B-1-19 B-2-19 B-3-19 0.43 0.27 0.35 1.25 18.49 15.52 33.02 5.83 25 - 26.5 30 - 31.5 22.5 - 24 55 - 56.5 25 - 26.5 30 - 31.5 22.5 - 24 55 - 56.5 41.5 34.5 37.6 67.8 54.5 63.6 54.7 31.8 37.5 25 37.5 37.5 5.394 2.743 3.85 9.331 0.823 0.36 0.397 4.327 0.292 0.177 0.117 1.602 Boring ID Depth WC (%)LL PL PI Cc Cu %Clay%Fines%Silt%Sand%Gravel Boring ID Depth D100 D60 D30 D10 USCS Classification %Cobbles 0.0 0.0 0.0 0.0 DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 SUPPORTING INFORMATION DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 UNIFIED SOIL CLASSIFICATION SYSTEM UNIFIED SOIL CLASSIFICATION SYSTEM Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests A Soil Classification Group Symbol Group Name B Coarse-Grained Soils: More than 50% retained on No. 200 sieve Gravels: More than 50% of coarse fraction retained on No. 4 sieve Clean Gravels: Less than 5% fines C Cu ‡ 4 and 1 £ Cc £ 3 E GW Well-graded gravel F Cu < 4 and/or [Cc<1 or Cc>3.0]E GP Poorly graded gravel F Gravels with Fines: More than 12% fines C Fines classify as ML or MH GM Silty gravel F, G, H Fines classify as CL or CH GC Clayey gravel F, G, H Sands: 50% or more of coarse fraction passes No. 4 sieve Clean Sands: Less than 5% fines D Cu ‡ 6 and 1 £ Cc £ 3 E SW Well-graded sand I Cu < 6 and/or [Cc<1 or Cc>3.0]E SP Poorly graded sand I Sands with Fines: More than 12% fines D Fines classify as ML or MH SM Silty sand G, H, I Fines classify as CL or CH SC Clayey sand G, H, I Fine-Grained Soils: 50% or more passes the No. 200 sieve Silts and Clays: Liquid limit less than 50 Inorganic:PI > 7 and plots on or above “A” line J CL Lean clay K, L, M PI < 4 or plots below “A” line J ML Silt K, L, M Organic:Liquid limit - oven dried < 0.75 OL Organic clay K, L, M, N Liquid limit - not dried Organic silt K, L, M, O Silts and Clays: Liquid limit 50 or more Inorganic:PI plots on or above “A” line CH Fat clay K, L, M PI plots below “A” line MH Elastic Silt K, L, M Organic:Liquid limit - oven dried < 0.75 OH Organic clay K, L, M, P Liquid limit - not dried Organic silt K, L, M, Q Highly organic soils:Primarily organic matter, dark in color, and organic odor PT Peat A Based on the material passing the 3-inch (75-mm) sieve. B If field sample contained cobbles or boulders, or both, add “with cobbles or boulders, or both” to group name. C Gravels with 5 to 12% fines require dual symbols: GW-GM well-graded gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay. D Sands with 5 to 12% fines require dual symbols: SW-SM well-graded sand with silt, SW-SC well-graded sand with clay, SP-SM poorly graded sand with silt, SP-SC poorly graded sand with clay. E Cu = D60/D10 Cc = 6010 2 30 DxD )(D F If soil contains ‡ 15% sand, add “with sand” to group name. G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM. H If fines are organic, add “with organic fines” to group name. I If soil contains ‡ 15% gravel, add “with gravel” to group name. J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay. K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel,” whichever is predominant. L If soil contains ‡ 30% plus No. 200 predominantly sand, add “sandy” to group name. MIf soil contains ‡ 30% plus No. 200, predominantly gravel, add “gravelly” to group name. N PI ‡ 4 and plots on or above “A” line. O PI < 4 or plots below “A” line. P PI plots on or above “A” line. Q PI plots below “A” line. DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1 Cedar River Apartments Renton, WA June 10, 2019 Terracon Project No. 81175025 0.25 to 0.50 > 4.00 2.00 to 4.00 1.00 to 2.00 0.50 to 1.00 less than 0.25 Unconfined Compressive Strength Qu, (tsf) Rock Core Grab Sample Standard Penetration Test Trace PLASTICITY DESCRIPTION Water levels indicated on the soil boring logs are the levels measured in the borehole at the times indicated. Groundwater level variations will occur over time. In low permeability soils, accurate determination of groundwater levels is not possible with short term water level observations. DESCRIPTION OF SYMBOLS AND ABBREVIATIONS GENERAL NOTES > 30 11 - 30 1 - 10Low Non-plastic Plasticity Index #4 to #200 sieve (4.75mm to 0.075mm Boulders 12 in. to 3 in. (300mm to 75mm)Cobbles 3 in. to #4 sieve (75mm to 4.75 mm)Gravel Sand Passing #200 sieve (0.075mm)Silt or Clay Particle Size Water Level After a Specified Period of Time Water Level After a Specified Period of Time Water Initially Encountered Soil classification is based on the Unified Soil Classification System. Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, and silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are defined on the basis of their in-place relative density and fine-grained soils on the basis of their consistency. GRAIN SIZE TERMINOLOGY RELATIVE PROPORTIONS OF FINESRELATIVE PROPORTIONS OF SAND AND GRAVEL DESCRIPTIVE SOIL CLASSIFICATION LOCATION AND ELEVATION NOTES SAMPLING WATER LEVEL FIELD TESTS N (HP) (T) (DCP) UC (PID) (OVA) Standard Penetration Test Resistance (Blows/Ft.) Hand Penetrometer Torvane Dynamic Cone Penetrometer Unconfined Compressive Strength Photo-Ionization Detector Organic Vapor Analyzer Medium 0Over 12 in. (300 mm) >12 5-12 <5 Percent of Dry Weight TermMajor Component of Sample Modifier With Trace Descriptive Term(s) of other constituents >30Modifier <15 Percent of Dry Weight Descriptive Term(s) of other constituents With 15-29 High Unless otherwise noted, Latitude and Longitude are approximately determined using a hand-held GPS device. The accuracy of such devices is variable. Surface elevation data annotated with +/- indicates that no actual topographical survey was conducted to confirm the surface elevation. Instead, the surface elevation was approximately determined from topographic maps of the area. Standard Penetration or N-Value Blows/Ft. Descriptive Term (Density) CONSISTENCY OF FINE-GRAINED SOILS Hard 15 - 30Very Stiff> 50Very Dense 8 - 15Stiff30 - 50Dense 4 - 8Medium Stiff10 - 29Medium Dense 2 - 4Soft4 - 9Loose 0 - 1Very Soft0 - 3Very Loose (50% or more passing the No. 200 sieve.) Consistency determined by laboratory shear strength testing, field visual-manual procedures or standard penetration resistance STRENGTH TERMS > 30 Descriptive Term (Consistency) Standard Penetration or N-Value Blows/Ft. RELATIVE DENSITY OF COARSE-GRAINED SOILS (More than 50% retained on No. 200 sieve.) Density determined by Standard Penetration Resistance DocuSign Envelope ID: 99BA427F-FE67-49CC-B142-9BE0760232C1