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Home My WebLink AboutRS_rockery_report_20161101_v1.pdf Rockery Wall Recommendations Thunder Hills Creek Sewer Alignment Grant Avenue South – I 405 Area Renton, Washington November 1, 2016 ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT i Table of Contents 1.0 INTRODUCTION .................................................................................................................. 1 2.0 PROJECT DESCRIPTION ...................................................................................................... 1 3.0 SITE DESCRIPTION .............................................................................................................. 1 4.0 SUBSURFACE DATA ............................................................................................................ 3 4.1.1 Site Investigation Program ................................................................................... 3 5.0 SOIL AND GROUNDWATER CONDITIONS ......................................................................... 4 5.1.1 Area Geology .................................................................................................... 4 5.1.2 Soil Conditions .................................................................................................... 4 6.0 GEOLOGIC HAZARDS ...................................................................................................... 6 6.1.1 Landslide Hazard................................................................................................ 6 6.1.2 Erosion Hazard .................................................................................................... 7 6.1.3 Seismic Hazard ................................................................................................... 8 7.0 DISCUSSION ....................................................................................................................... 8 7.1.1 General ............................................................................................................... 8 8.0 RECOMMENDATIONS ........................................................................................................ 9 8.1 SITE PREPARATION ............................................................................................................. 9 8.2 TEMPORARY EXCAVATIONS ............................................................................................10 8.3 EROSION AND SEDIMENT CONTROL ...............................................................................11 8.4 ROCKERY WALLS ..............................................................................................................12 8.5 UTILITIES ............................................................................................................................19 8.6 GROUNDWATER INFLUENCE ON CONSTRUCTION .........................................................20 8.7 ACCESS ROADWAY CONSTRUCTION .............................................................................20 9.0 CONSTRUCTION FIELD REVIEWS .......................................................................................21 10.0 CLOSURE ..........................................................................................................................21 ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 Table of Contents (Continued) ii LIST OF APPENDICES Appendix A — Statement of General Conditions Appendix B — Figures Appendix C — Boring Logs & Rockery Spreadsheets ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 1 1.0 Introduction In accordance with authorization by the City of Renton, Stantec has completed a geotechnical report with rockery wall recommendations for the Thunder Hills Creek Sewer Alignment project located in Renton, Washington. The purpose of this report was to summarize the known and anticipated geologic conditions within the project area and provide recommendations for rockery wall construction, mass grading, roadway construction, utility backfill, and rock buttress placement. The scope of work for the study consisted of multiple levels of field investigations and document reviews followed by engineering analyses to prepare this report. Recommendations presented herein pertain to various geotechnical aspects of the proposed project, including grading, utility placement, utilities, rockery wall construction, and rock buttressing. 2.0 Project Description The project consists of rehabilitating (lining) the existing sewer line along Thunder Hills Creek, placement of about 1,500 feet of new 12 inch diameter HDPE sewer pipe, 6 new sanitary sewer manholes (SSMH), re-grading of the existing access roadway, and placement/construction of rockery walls and rock buttresses. New manholes will be placed to depths ranging from 7 to 12 feet below existing site grades. The access roadway improvements include apron widening at the south end of the alignment (Grant Avenue S.), a turnaround at Stations 7+50 to 8+40, and hammerhead improvements near Station 16+00. North of about Station 7+50, the access roadway will be re-graded to allow access with small equipment. Re-grading and slope modifications are proposed locally along the alignment. In general, these include cuts of up to 4 feet and fills on the order of 2 feet or less. 3.0 Site Description The Thunder Hills Creek project area is located between I -405 and Grant Avenue South, just east of the Berkshire Apartment Home development (Figure 1). The site area includes existing developed areas along the east side of Thunder Hills Creek south of about Station 13+40 and along the west side of Thunder Hills Creek north of Station 12+50. ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 2 In general, the area of proposed development will be limited to the valley bottom along existing roadway alignments and adjacent embankments. Figures 2 through show the general site layout, wall locations, and utility alignment. The site consists of the existing sewer interceptor alignment through the Thunder Hills Creek valley along with a gravel improved access roadway located adjacent to the stream for much of the alignment. The access roadway has been damaged significantly by soil movement and erosion near Station 6+50 (Figure 2). North of this location, the roadway is improved (partially) with quarry rock north to a flat area near I-405. South of Station 7+50, variable amounts of sediment are present in the stream channel. North of this area, the stream has incised into the underlying sandstone (Renton Formation). Four to 12 inch sized quarry rock is present in the stream bed and banks in many areas. Larger quarry rock, generally ½ to 4 man sized basalt, has been used to stabilize the stream banks and/or to prevent ongoing stream erosion. Specifically in the vicinity of Station 6+00, large quarry rock has been used to fill the stream channel. Rock filled gabion walls, generally 4 to 6 feet in height, are located between the access roadway/path and Thunder Hills Creek north of Station 5+50 and locally upstream along the east side of the stream. For the most part, the gabion baskets have deteriorated significantly and in places the walls are somewhat overturned. The gabion walls appear to have limited functionality as retaining structures for the roadway and sewer line. The slopes extending downward into the Thunder Hills Creek valley between Stations 0+25 and 6+40 are very steep, with magnitudes of 100 to 150 percent. There are localized slope areas that are near vertical (200 percent magnitude) to overturned due to excavation, sloughing, and/or landslide activity. Several rockeries are located along the east and west sides of the access roadway between Stations 4+80 and 6+50. The rockeries are comprised of 1 to 2 man sized basalt and are up to 7 feet in height. The rockeries are loosely constructed. There is evidence that shallow landslide activity occurs periodically along portions of the slope west of the access roadway north of Station 5+50. Several large, but shallow, landslides have occurred within the last several years north of Station 3+50. The slides appear to consist of the upper colluvium (1 to 4 feet thick) sliding off of the underlying sandstone. The slides extend upslope between 10 and 50 feet and are up to 70 feet wide. South of Station 13+40, a majority of the natural slopes along the east side of the stream have moderate magnitudes ranging from 15 to 40 percent. Locally along the east side of the access road, there are steep to undermined excavations up to 10 feet in height. These slopes are generally 100 percent or steeper in magnitude. Exposed soils are consistent with glacial till. ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 3 The site is bordered to the north by I -405, to the west by the Berkshire Apartment Homes, to the east by undeveloped land (easements) and single family residences, and to the south by Thunder Hills Creek, easements, and residential developments. 4.0 Subsurface Data 4.1.1 Site Investigation Program The geotechnical field investigation program was completed on October 17th and 20th, 2014 and included drilling and sampling four hollow stem auger borings drilled by a Stantec subcontractor using a limited access drill rig. The borings were located at or near pre- determined locations and extended approximately 5 to 25 feet below the existing site grades. Additional hand borings were excavated on August 12, 2016 to verify shallow soil conditions where rockery walls may be constructed. The soils encountered were logged in the field during the exploration and are described in accordance with the Unified Soil Classification System (USCS). Disturbed soil samples were obtained by using a 140 pound hammer free falling a vertical distance of 30 inches for the borings. The summation of hammer-blows required to drive the sampler the final 12 -inches of an 18-inch sample length is defined as the Standard Penetration Resistance, or N-value for a 140 pound hammer and 2 inch outside diameter split spoon sampler. The uncorrected blow count is presented graphically on the boring logs in Appendix C. The resistance, or “N” value, provides a measure of the relative density of granular soils and the consistency of cohesive soils. Our report discussions regarding soil density as well as engineering parameters are based on the N values. A Stantec field representative directed the drilling program, collected disturbed soil samples from split spoon sampler tubes, classified the encountered soils, kept a det ailed log of each auger hole, and observed and recorded pertinent site features. The results of the drilling and sampling are presented on the boring logs enclosed in Appendix C. We also reviewed six boring logs from a geotechnical investigation conducted by Soil and Environmental Engineers, Inc. (S&EE) in 2011. This report was conducted to develop solutions to retain/protect the existing sewer line in the lower portion of the Thunder Hills Creek valley. ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 4 5.0 Soil and Groundwater Conditions 5.1.1 Area Geology The site lies within the Puget Lowland. The lowland is part of a regional north -south trending trough that extends from southwestern British Columbia to near Eugene, Oregon. North of Olympia, Washington, this lowland is glacially carved, with a depositional and erosional history including at least four separate glacial advances/retreats. The Puget Lowland is bounded to the west by the Olympic Mountains and to the east by the Cascade Range. The lowland is filled with glacial and nonglacial sediments consi sting of interbedded gravel, sand, silt, till, and peat lenses. The Geologic Map of King County, indicates that the site is located near the contacts between Vashon Glacial Till and Tertiary Bedrock. Vashon Glacial Till is typically characterized by an unsorted, nonstratified mixture of clay, silt, sand, gravel, cobbles and boulders in variable quantities. These materials are typically dense and relatively impermeable. The poor sorting reflects the mixing of the materials as these sediments were overridden and incorporated by the glacial ice. Tertiary Bedrock in this area consists of the Renton Formation. The Renton Formation includes feldspathic fine to medium grained sandstone with beds of coal, carbonaceous siltstone, and claystone. Tertiary Bedrock locally outcrops south of I -90 and the Seattle Fault Zone due to uplift associated with seismic activity. 5.1.2 Soil Conditions Details of the encountered soil conditions are presented on the boring logs in Appendix C. The detailed soil description on these logs should be referred to in preference to the generalized descriptions below. Boring B-1 In Boring B-1, we encountered approximately 6 inches of topsoil and vegetation underlain by approximately 5 feet of medium dense to dense, silty-fine to medium grained sand with variable amounts of gravel and debris (Fill). This layer was underlain by stiff to very stiff silt with variable amounts of sand and woody debris (Fill). The silt layer was underlain by stiff silt with variable amounts of sand, gravel, and trace amounts of woody debris (Highly Weathered Renton Formation). These materials were underlain by medium dense, silty-sand with clasts of ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 5 weathered sandstone (Weathered Renton Formation), which continued to the termination depth of the boring. Borings B-2 and B-3 In Borings B-2 and B-3, we encountered approximately 10 to 12 inches of vegetation and topsoil underlain by approximately 5 feet of medium dense, silty-fine to medium grained sand with variable amounts of gravel (Fill). This layer was underlain by dense to very dense, silty-fine to medium grained sand with variable amounts of gravel (Glacial Till), which continued to the termination depths of these borings. Boring B-4 In Boring B-4, we encountered approximately 8 inches of angular rock underl ain by approximately 4 feet of loose to medium dense, silty-fine to medium grained sand with variable amounts of gravel (Fill). This layer was underlain by hard sandstone (Renton Formation), which continued to the termination depth of the boring (refusal). Observed Soil Conditions South of Station 13+40 South of Station 13+40, the shallow subsurface soils generally include up to 2 feet of vegetation and topsoil underlain by 2 to 4 feet of loose to medium dense, silty-fine to medium grained sand with variable amounts of gravel (Weathered Glacial Till). This layer is underlain by dense to very dense, silty-fine to medium grained sand with variable amounts of gravel (Glacial Till). There are many open cuts along the east side of the access roadway. We probed the exposed soils at many locations and encountered medium dense to dense glacial till. Groundwater At the time of our investigation, groundwater was encountered in Boring B -4 at approximately 4.5 feet below the existing site grade. Groundwater was not encountered in any of the other explorations at the date of our investigation. We anticipate that groundwater in the Thunder Hills Creek valley is primarily influenced by area streams and surface water runoff/infiltrating surface waters . There are areas of the site near I-405 where surface water and groundwater is at the same level (ground surface) and areas where groundwater is not encountered below stream depths due to stream channel confinement within the Renton Formation sandstone. Groundwater may be found perched within upper loose sediments or fill, or between weathered and unweathered geologic units. There are numerous drains extending downslope toward the access road from the east south of Station 13+40. At the time of our visit, no water was observed flowing from these pipes; however, there could be runoff during the wetter months of the year. ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 6 We anticipate low to moderate seasonal seepage from the valley/channel sidewalls contributing to the overall volume in Thunder Hills Creek. A majority of volume contribution to the stream is from drainage conveyance from nearby residential developments and tributary streams. Water levels at the time of the field investigation may be different from those encountered during the construction phase of the project. 6.0 Geologic Hazards 6.1.1 Landslide Hazard Typically, slopes with magnitudes greater than about 40 percent and vertical relief of at least 10 feet can be classified as geologically hazardous (steep slope/landslide hazards). Many of the slopes that extend into the Thunder Hills Creek valley meet these criteria. North of Station 6+00 There are many areas north of Station 6+00 that range in magnitude between 80 and 150 percent. These slopes are covered with up to several feet of weathered soils (colluvium) and are mostly vegetated with trees and undergrowth. We observed several relatively recent landslides in the area north of Station 2+50, primarily along the steep slopes along the west side of Thunder Hills Creek. These slides appear to be relatively shallow, consisting of colluvium sliding off of the underlying sandstone. We did not observe evidence of deep-seated landslide activity within the valley. It is our opinion that the contributing causes for landslide activity in the north portion of Thunde r Hills Creek valley include previous excavations for access roadway construction, surface water and spring/seep activity along the slopes, and the presence of loose colluvium over relatively impermeable, hard sandstone at steep inclinations. Slope stability analyses are not warranted for the upper portions of the slopes extending into the Thunder Hills Creek valley as their relative stability can be visually assessed. Factors that influence the relative factors of safety along the slope areas include surface water , vegetation and root systems, colluvium/fill density and thickness, and slope magnitude. We anticipate lower factors of safety and higher probability of landslide activity to occur from approximately November to May when precipitation is highest. ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 7 South of Station 6+00 In general, the slope magnitudes south of Station 6+00 range from 30 to 100 percent. There are local excavations along the existing roadway that are near vertical to slightly overturned (undercut). These excavations are up to 8 feet in height and some minor sloughing was observed. The dense glacial till that underlies these areas are typically resistant to global instability. The proposed rockery construction and/or re-grading of slope cuts will reduce the erosion and sloughing potential of these areas. 6.1.2 Erosion Hazard The Natural Resources Conservation Services (NRCS) maps for King County indicate that the project area and directly adjacent side slopes are underlain by Alderwood and Kitsap soils (very steep), Alderwood gravelly sandy loam (8 to 30 percent slopes) and Beausite gravelly sandy loam (15 to 30 percent slopes). Since the project is located within an actively incising stream environment adjacent to very steep slope areas, all soils should be considered to have “Severe” to “Very Severe” erosion potential. It is our opinion that soil erosion potential at this project site, if grading activities are proposed, can be reduced through surface water runoff control and local removal of problem soil areas (discussed in Section 8.1). Typically erosion of exposed soils will be most noticeable during periods of rainfall and may be controlled by the use of normal temporary erosion control measures, such as silt fences, hay bales, mulching, control ditches and diversion trenches. The typical wet weather season, with regard to site grading, is from October 31st to April 1st. Erosion control measures should be in place before the onset of wet weather. While erosion of the sandstone that underlies the site between Stations 0+00 and 5+50 will oc cur at a low to very low rate over the lifespan of the sewer line (80 years), large storm events and long term erosion of the sandstone could erode the existing gabion walls and slope between the stream and sewer line. To reduce adverse effects of soil and slope erosion caused by Thunder Hills Creek, permanent erosion prevention systems should be constructed. Large rock buttressing embedded into the unweathered sandstone should provide adequate protection for the sewer line and access roadway. 6.1.3 Seismic Hazard We encountered generally medium dense to very dense soils and locally soft rock at the project site. The overall subsurface profile corresponds to a Site Class D as defined by Chapter 20 of ASCE 7 (Table 20.3-1) and referenced in Table 1613.3.2 of the 2015 International Building Code (2015 IBC). A Site Class D applies to an overall profile consisting of medium dense/stiff to very dense/hard materials within the upper 100 feet. ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 8 Areas of the site, including areas directly underlain by soft bedrock (sandstone), would be considered as a Site Class C, soft rock profile. We do not anticipate the need to utilize seismic parameters from this profile as part of the currently proposed project and therefore they have not been included. We referenced the U.S. Geological Survey (USGS) Earthquake Hazards Program Website (seismic calculator) to obtain values for SS, S1, Fa, and Fv. The USGS website includes the most updated published data on seismic conditions. The site specific seismic design parameters and adjus ted maximum spectral response acceleration parameters are as follows: PGA (Peak Ground Acceleration, in percent of g) 32.24 (10% Probability of Exceedence in 50 years) 62.52 (2% Probability of Exceedence in 50 years) SS 141.10% of g S1 48.30% of g Additional seismic considerations include liquefaction potential and amplification of ground motions by soft/loose soil deposits. The liquefaction potential is highest for loose sand with a high groundwater table. The dense to very dense, glacially consolida ted materials and bedrock that underlie the site have a very low potential for liquefaction. 7.0 Discussion 7.1.1 General It may not be economically feasible to construct preventative structures to eliminate shallow landslide activity which originates higher up the steep slopes above the proposed/existing access roadway in the north portion of the site. At a minimum, we recommend performing remedial excavation work to reduce the likelihood and adverse effects of shallow colluvial slides on the proposed/existing access roadway along with rockery wall construction, and select hazardous tree removal. Rock buttresses should be constructed between the access roadway and stream within the north portion of the alignment to prevent erosion/undercutting of the roadway and sewer line by Thunder Hills Creek over the design lifespan of the sewer line (approximately 80 years). These would replace existing gabion walls which are failing in places. ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 9 Rockery walls may be constructed along localized steep excavations along the east side of the access roadway may be re-graded or faced with rockery walls to reduce sloughing and erosion over time. A combination of rockery walls with re -graded back slopes is suitable in lieu of constructing very tall rockery walls or extending lower magnitude permanent slopes beyond the construction and/or easement limits. 8.0 Recommendations 8.1 SITE PREPARATION In general, site preparation should consist of vegetation and topsoil removal from proposed excavation/improvement areas. Based on observations from the site investigation program and site reconnaissance work, it is anticipated that the stripping depth will generally be less than 12 inches where topsoil and vegetation are present. The excavated material is not suitable as structural fill but could be used as fill material in non-settlement sensitive areas such as landscaping. In these non-settlement sensitive areas, the fill should be placed in maximum 12 inch thick lifts that should be compacted to at least 90 percent of the modified proctor (ASTM D 1557 Test Method) maximum dry density. As needed, leaning trees and other trees designated as hazard trees located in critical areas, may be removed during site preparation. It may be useful to leave root systems in place depending on the location of the hazard trees. We can provide recommendations on which trees are suitable for full removal or partial removal upon request. Native soils are generally considered suitable for use as structural fill provided they are within 3 percent of the optimum moisture content and free of deleterious materials. It should be noted that these materials are typically suitable for structural fill only during the summer months and are highly moisture sensitive due to their fines content. Imported structural fill should consist of a sand and gravel mixture with a maximum grain size of 3 inches and less than 5 percent fines (material passing the U.S. Standard No. 200 Sieve). Structural fill should be placed in maximum lift thicknesses of 12 inches and should be compacted to a minimum of 95 percent of the modified proctor maximum dry density, as determined by the ASTM D 1557 test method. ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 10 8.2 TEMPORARY EXCAVATIONS Based on our understanding of the project, grading associated with access road construction will include cuts on the order of 4 feet or less. Utility excavations may be up to 12 feet below existing grades; however, we anticipate that temporary shoring will be used for these excavations. If any utility excavations will be openly excavated, we recommend they be sloped no steeper than 1H:1V in medium dense native soils and 3/4H:1V in dense to very dense native soils. Recommendations for temporary excavations for rockery and buttress construction are addressed separately in Section 8.4. If an excavation is subject to heavy vibration or surcharge loads, we recommend that the excavation be sloped no steeper than 1.5H:1V and 1H:1V, respectively as above, where room permits. If groundwater is encountered, lower declinations may be required. In general, excavations in slightly weathered sandstone may be stable up to a vertical condition; however, we do not anticipate the need to excavate into sandstone other than removing loose colluvium from existing slopes along the west side of the proposed access roadway. In these areas, we recommend scraping the loose materials and any loose sandstone that readily comes free from the rock faces only. Again, Stantec should be on site to observe the conditions during construction and provide location-specific recommendations. All temporary cuts should be in accordance with the Washington Administrative Code (WAC) Part N, Excavation, Trenching, and Shoring. The temporary slopes should be visually inspected daily by a qualified person during construction activities and the inspections should be documented in daily reports. The contractor is responsible for maintaining the stability of the temporary cut slopes and reducing slope erosion during construction. The temporary cut slopes should be covered with visqueen to help reduce erosion during wet weather, and the slopes should be closely monitored until the permanent retaining systems or slope configurations are complete. Materials should not be stored or equipment operated within 10 feet of the top of any temporary cut slope. Soil conditions may not be completely known from the geotechnical investigation. In the case of temporary cuts, the existing soil conditions may not be completely revealed until the excavation work exposes the soil. Typically, as excavation work progresses , the maximum inclination of the temporary slopes will need to be re -evaluated by the geotechnical engineer so that supplemental recommendations can be made. Soil and groundwater conditions can be highly variable. Scheduling for soil work will need to be adjustable, t o deal with unanticipated conditions, so that the project can proceed and required deadlines can be met. ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 11 If any variations or undesirable conditions are encountered during construction, Stantec should be notified so that supplemental recommendations can be made. If room constraints or groundwater conditions do not permit temporary slopes to be cut to the maximum angles allowed by the WAC, temporary shoring systems may be required. The contractor should be responsible for developing temporary shoring systems, if needed. We recommend that Stantec and the project structural engineer review temporary shoring designs prior to installation, to verify the suitability of the proposed systems. 8.3 EROSION AND SEDIMENT CONTROL Erosion and sediment control (ESC) is used to reduce the transportation of eroded sediment to wetlands, streams, lakes, drainage systems, and adjacent properties. Erosion and sediment control measures should be implemented and these measures should be in general accordance with local regulations. At a minimum, the following basic recommendations should be incorporated into the design of the erosion and sediment control features for the site:  Schedule the soil, foundation, utility, and other work requiring excavation or the disturbance of the site soils, to take place during the dry season (generally June through September). However, provided precautions are taken using Best Management Practices (BMP’s), certain grading activities can be completed during the wet season (generally October through April).  All site work should be completed and stabilized as quickly as possible.  Additional perimeter erosion and sediment control features may be required to reduce the possibility of sediment entering the surface water. This may include additional silt fences, silt fences with a higher Apparent Opening Size (AOS), construction of a berm, or other filtration systems.  Any runoff generated by dewatering discharge should be treated through construction of a sediment trap if there is sufficient space. If space is limited, other filtration methods will need to be incorporated. Specifically for this project, site grading should only be performed during the summer months (late June through mid-September) when the creek is at it lower levels and surface waters w ill be less prevalent. Additional erosion control measures will likely be required between the proposed roadway and Thunder Hills Creek during construction due to the presence of wetlands. There are areas where loose colluvium overlies hard sandstone at s teep angles between Station 0+50 and 4+00. The removal of soils and trees from site slopes should be observed by the geotechnical engineer as slope stability above these locations could be adversely affected. Replacement of loose soils with quarry rock may be warranted. In general, we recommend removal of trees and colluvium only where necessary and with geotechnical oversight. ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 12 8.4 ROCKERY WALLS Rockery walls are not considered as engineered gravity retaining walls mainly because the structure is not an integral as the rocks are just siting and they are not structurally connected to each other. They generally function as erosion protection for the materials they face that are themselves stable, which should be dense to very dense soils with adequate fines, p referably glacially consolidated materials in the region. Based on our observations at the site, the underlying materials appear to consist of dense glacial till and/or hard sandstone. The shallow soil conditions along the proposed alignment and adjacent roadway areas generally consist of loose to medium dense weathered glacial till overlying dense to very dense unweathered glacial till. Sandstone is locally exposed north of about Station 6+00. Because of the soil density, rockery walls are generally suitable to protect roadway excavations from erosion. Glacial till or bedrock are in our opinion, the only geologic units in the Puget Sound region suitable for rockery facing. At this site, rockery walls will be up to 10 feet in exposed height. We recommend a minimum of 12 inches of embedment for walls between 4 and 10 feet tall and 6 inches for walls with exposed heights of 4 feet or less. All walls should have a minimum batter of 6V:1H (vertical to horizontal) and be backfilled with 2 to 4 inch sized angular quarry rock. Rockery drainage recommendations can be found below. All rockeries should be constructed per the Associated Rockery Contractors (ARC) guidelines (http://www.ceogeo.org/schedule/09244404pm_Current%202013%20ARC%20Rockery%20Constr uction%20Guidelines.pdf ) with geotechnical monitoring of the keyway excavation, drainage, rock placement, backfill, and excavation work by the geotechnical engineer. ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 13 Wall Locations Rockery walls will be necessary locally along the upslope side of the access roadway between Stations 4+40 and 27+35. During our field assessments, we observed undermined cuts and local near-vertical excavations along the upslope (east) side of the access roadway at several locations. The roadway will be widened up to several feet during the construction phases of the project and these excavations should be protected from erosion. General locations of rockery walls are as follows: Wall Designation Approximate Stationing Estimated Height Range No. 1 4+40 to 6+70 Up to 8 Feet No. 2 7+50 to 8+45 Up to 10 Feet No. 3 13+40 to 14+25 Up to 6 Feet No. 4 16+85 to 20+20 Up to 10 Feet No. 5 20+55 to 24+60 Up to 10 Feet No. 6 25+05 to 27+35 Up to 8 Feet Field conditions may warrant alterations in wall heights, slope inclinations above the walls, rockery lengths, and backfill requirements. Typically, these adjustments are relatively minor and can be made in the field by the contractor and geotechnical engineer/personnel. Rockery Wall Design Our rockery design recommendations refer to various rock sizes. The Washington State Department of Transportation (WSDOT) uses the following table when referring to larger size rocks and boulders: ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 14 Rock Size Rock Weight Ave. Dimensions Half Man 25 - 50lbs 6” - 12" One Man 50 - 200lbs 12" - 18" Two Man 200 - 700lbs 18" - 28" Three Man 700 - 2,000lbs 28" - 36" Four Man 2,000 - 4,000lbs 36" - 48" Five Man 4,000 - 6,000lbs 48" - 54" Six Man 6,000 - 8,000lbs 54" - 60" Design Parameters The following soil parameters were used in rockery design calculations: Soil Type Friction Angle Cohesion Unit Weight Retained Soils (Glacial Till) 36 degrees 0 psf 120 pcf Foundation Soils (Glacial Till) 36 degrees 0 psf 120 pcf psf = pounds per square foot pcf = pounds per cubic foot A unit weight of 155 pcf was used for large rocks. The designs also utilized an assumed wall batter of 6V:1H (Vertical to Horizontal) and variable back slope angles up to a maximum of 2H:1 (Horizontal to Vertical). The following tables indicate recommended minimum rock sizes for use in rockery wall construction for various wall heights and back slope angles. All heights shown in the tables are for the exposed wall heights, not total height. All walls over 4 feet in exposed height should have a minimum 12 inch embedment into the native soils. ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 15 4 Feet Tall Rockery Wall Back Slope Angle Base Rock Size (Min. in Feet) Top Rock Size (Min. in Feet) Level to 4H:1V 2 1.5 4H:1V to 2.5H:1V 2.5 2 2H:1V 2.5 2 5 Feet Tall Rockery Wall Back Slope Angle Base Rock Size (Min. in Feet) Top Rock Size (Min. in Feet) Level to 4H:1V 2.5 2 4H:1V to 2.5H:1V 2.5 2 2H:1V 3 2 6 Feet Tall Rockery Wall Back Slope Angle Base Rock Size (Min. in Feet) Top Rock Size (Min. in Feet) Level to 4H:1V 3 2 4H:1V to 2.5H:1V 3 2.5 2H:1V 3.5 2.5 ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 16 7 Feet Tall Rockery Wall Back Slope Angle Base Rock Size (Min. in Feet) Top Rock Size (Min. in Feet) Level to 4H:1V 3.5 2.5 4H:1V to 2.5H:1V 3.5 2.5 2H:1V 4 2.5 8 Feet Tall Rockery Wall Back Slope Angle Base Rock Size (Min. in Feet) Top Rock Size (Min. in Feet) Level to 4H:1V 3.5 3 4H:1V to 2.5H:1V 3.5 3 2H:1V 4 3 9 Feet Tall Rockery Wall Back Slope Angle Base Rock Size (Min. in Feet) Top Rock Size (Min. in Feet) Level to 4H:1V 3.5 2.5 4H:1V to 2.5H:1V 4 3 2H:1V 4.5 3.5 ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 17 10 Feet Tall Rockery Wall Back Slope Angle Base Rock Size (Min. in Feet) Top Rock Size (Min. in Feet) Level to 4H:1V 4 3.5 4H:1V to 2.5H:1V 4 3.5 2H:1V 5 3.5 Wall Subgrade Preparation To prepare the wall areas for construction, all vegetation, organic surface soils, and other deleterious materials including any existing structures, foundations or abandoned utility lines should be stripped and removed from the keyway areas. Rockery keyways should be excavated to the level of medium dense or firmer native soils. If excessively soft or yielding areas are present, and cannot be stabilized in place by compaction, they should be cut to firm bearing soil and filled to grade with structural fill. If the depth to remove the unsuitable soil is excessive, we should be contacted to provide recommendations as necessary for the successful completion of the walls, or to re-evaluate the wall designs based on actual site conditions. Quarry rock (2-8 inches in size) is recommended as fill behind rockery walls. We recommend a minimum width of 1.5 feet of quarry rock be placed between the rockery and native cut face. Wall Drainage To guard against hydrostatic pressure development, drainage must be installed behind the walls. Typically, rockery walls are backfilled with clean angular rock (2-4 quarry rock) which extends from the base to the top of the wall and 18 to 24 inches in width. In addition to this rock placement, a drainage collector system consisting of 4-inch perforated PVC pipe should be placed behind the wall to provide an outlet for any accumulated water. Throughout the project, it is paramount that the geotechnical engineer periodically monitors all rockery walls constructed against cuts or fills exceeding 4 feet in height. It is important for the engineer to verify that the construction and materials meet the original geotechnical recommendations and specifications. The geotechnical engineer should also develop a ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 18 monitoring plan for visiting the site. For instance, ARC (1991) recommends for a single tiered rockery wall that is less than 50 feet in length should require a minimum of at least one visit along with daily inspections by a project engineer/geologist. The geotechnical engineer must maintain records of the nature and condition of the wall under observation. In addition, the engineer should verify the soundness of the rocks selected for the rockery wall by striking the selected rocks with a geology hammer. A loud ring suggests strong competent rock. Conversely, a dull thud will suggest poor rock not fit for a rockery wall. Rock Buttresses As needed, primarily in the area between Stations 2+00 to 5+50, rock buttresses may be utilized to support the access roadway and prevent lateral pipe movements and/or erosion/undercutting of the sewer line. However, any type of retaining structure will only be effective if they are embedded into the underlying sandstone. In other words, fill material or soil deposits that are used to support retaining structures could be easily eroded by t he stream during storm events when flows are high in volume and velocity, potentially causing the structures to fail (as observed with the current gabion walls). Rock buttresses may be used to protect the existing sewer line and access roadway from stream erosion and sloughing in the north portion of the project site. In general, buttresses should be constructed between the access path/roadway and stream channel. Existing dilapidated gabion structures should be removed as part of grading activities. Much of the angular rock in the gabion baskets may be utilized between large rocks in the buttresses. We recommend that quarry rock used as buttress materi al be 4-man sized or larger. Condition- specific recommendations may be made during construction by Stantec if subsurface conditions warrant. In general, buttressing should consist of the following:  Gabion wall removal  Loose soil removal and temporary excavation creation (generally between 3/4H:1V and 1.5H:1V)  Excavation of a keyway at the toe of the buttress (at least 18 inches into underlying dense soils or weathered sandstone)  Placement of large angular basalt with interstitial quarry rock (as void fill) Stantec should be on site to observe gabion removal, keyway excavations, and rock placement. ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 19 8.5 UTILITIES Sewer line trenches should be excavated according to accepted engineering practices following OSHA (Occupational Safety and Health Administration) standards, by a contractor experienced in such work. The contractor is responsible for the safety of open trenches. Traffic and vibration adjacent to trench walls should be reduced; cyclic wetting and drying of excavation side slopes should be avoided. Depending upon the location and depth of some utility trenches, groundwater flow into open excavations could be experienced, especially during or shortly following periods of precipitation. In general, silty soils were encountered at shallow depths in the explorations at this site. At this site, these soils have variable density and minimal cohesion and will have a tendency to cave or slough in excavations. Shoring or sloping back trench sidewalls is required within these soils. If sewer line excavations extend deep enough to encounter sandstone (not anticipated), rock chipping/breaking equipment would likely be required to allow for excavation. Excavations in sandstone should be adequately safe to remain vertical for a significant amount of time. All utility trench backfill should consist of imported structural fill. Certain on site soils may be suitable for use as backfill in landscaping areas during the summer months; however, we should evaluate these soils at that time to determine their moisture levels. The upper 5 feet of utility trench backfill placed in pavement areas should be compacted to at least 95 percent of the maximum dry density based on ASTM Test Method D1557. Below 5 feet and in landscaping areas, utility trench backfill in pavement areas should be compacted to at least 90 percent of the maximum dry density based on ASTM Test Method D1557. Pipe bedding should consist of 5/8” crushed rock compacted to at least 90 percent of the maximum dry density. The contractor is responsible for removing all water-sensitive soils from the trenches regardless of the backfill location and compaction requirements. Depending on the depth and location of the proposed utilities, we anticipate the need to re-compact existing fill soils below the utility structures and pipes. The contractor should use appropriate equipment and methods to avoid damage to the utilities and/or structures during fill placement and compaction procedures. ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 20 8.6 GROUNDWATER INFLUENCE ON CONSTRUCTION We do not expect groundwater to be encountered during grading or placement of the rockery walls. If groundwater is encountered, it would likely be perched on underlying very dense glacial till and volumes would be expected to be light. North of Station 6+00, we would anticipate light to moderate seepage emanating from the side slope where buttressing will be placed. Flows are expected to extend from the ground surface down to the level of the sandstone (upper 4 to 5 feet). Boring B-1 was located near Thunder Hills Creek and extended approximately 20 feet below the stream level. We did not encounter groundwater in this boring, which indicates that the stream is (at least) locally confined within the channel zones. Groundwater seepage may be encountered in sewer trench and manhole excavations where somewhat more permeable soils overlie dense to very dense glacial till or sandstone. We would anticipate any seepage to migrate laterally along the weathered-unweathered till contact and flow downward into existing sewer line backfill materials. Provided the work occurs during the dry season (June through September), we anticipate that typical sump pumps would be suitabl e to dewater the areas during construction. In order to reduce the rate of downgradient groundwater flow in sewer trenches following construction, we recommend bedding the sewer lines with 5/8” minus crushed rock. The rock should be compacted to at least 90 percent of the modified proctor. If significant volumes of groundwater are encountered in utility excavations, we can provide location-specific recommendations for mitigation, if necessary. These may include lateral drainage placement to reduce/divert groundwater toward the stream, or modifications to bedding and backfill. 8.7 ACCESS ROADWAY CONSTRUCTION The existing access roadway is underlain by several inches of variably compacted crushed rock (5/8” to 1-1/4” minus) which is underlain by variable density fill and native soils. We antic ipate that the fill consists of previously excavated native soils (silty-sand with gravel). In general, the fill likely ranges from a few inches in thickness up to a few feet; however, up to 15 feet of fill was observed in borings in the vicinity of Stati on 7+00. The fill and native soils have high fines content and should be considered to be very moisture sensitive. These materials will degrade when exposed to wet weather conditions. We expect that the upper 1 to 2 feet of existing soils may degrade during construction, primarily due to heavy traffic loads. If this occurs, the degraded soils should be removed and replaced with suitable structural fill placed and compacted per Section 8.1.1. ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 21 9.0 Construction Field Reviews Stantec should be retained to provide part time field review during construction in order to verify that the soil conditions encountered are consistent with our design assumptions and that the intent of our recommendations is being met. This will require field and engineering review to:  Observe all aspects of rockery, rock buttress, and access roadway construction  Monitor temporary excavations, slope stability, and grading activities  Density testing to verify compaction of structural fills  Utility, backfill, and bedding placement Geotechnical design services should also be anticipated during the subsequent final design phase to support the structural design and address specific issues arising during this phase. Field and engineering review services will also be required during the construction phase in order to provide a Final Letter for the project. 10.0 Closure This report was prepared for the exclusive use of the City of Renton and their appointed consultants. Any use of this report or the material contained herein by third parties, or for other than the intended purpose, should first be approved in writing by Stantec. The recommendations contained in this report are based on limited data from provided test holes, and proposed construction. We should be provided with the final plans and specifications to verify that the intent of our recommendations has been implemented into the design. Use of this report is subject to the Statement of General Conditions provided in Appendix A. It is the responsibility of the City of Renton who is identified as “the Client” within the Statement of General Conditions, and its agents to review the conditions and to notify Stantec should any of these not be satisfied. ROCKERY WALL RECOMMENDATIONS THUNDER HILLS CREEK SEWER ALIGNMENT November 1, 2016 22 Respectfully submitted, Stantec Consulting Services, Inc. Original signed by: Original signed by: 11/1/16 Phil Haberman, P.G., P.E.G. Sean Caraway, P.E. Senior Engineering Geologist Senior Geotechnical Engineer PH/sc APPENDIX A Statement of General Conditions Statement of General Conditions USE OF THIS REPORT: This report has been prepared for the sole benefit of the Client or its agent and may not be used by any third party without the express written consent of Stantec Consulting Services, Inc. and the Client. Any use which a third party makes of this report is the responsibility of such third party. BASIS OF THE REPORT: The information, opinions, and/or recommendations made in this report are in accordance with Stantec Consulting Services, Inc.’s present understanding of the site specific project as described by the Client. The applicability of these is restricted to the site conditions encountered at the time of the investigation or study. If the proposed site specific project differs or is modified from what is described in this report or if the site conditions are altered, this report is no longer valid unless Stantec Consulting Services, Inc. is requested by the Client to review and revise the report to reflect the differing or modified project specifics and/or the altered site conditions. STANDARD OF CARE: Preparation of this report, and all associated work, was carried out in accordance with the normally accepted standard of care in the state of execution for the specific professional service provided to the Client. No other warranty is made. INTERPRETATION OF SITE CONDITIONS: Soil, rock, or other material descriptions, and statements regarding their condition, made in this report are based on site conditions encountered by Stantec Consulting Services, Inc. at the time of the work and at the specific testing and/or sampling locations. Classifications and statements of condition have been made in accordance with normally accepted practices which are judgmental in nature; no specific description should be considered exact, but rather reflective of the anticipated material behavior. Extrapolation of in situ conditions can only be made to some limited extent beyond the sampling or test points. The extent depends on variability of the soil, rock and groundwater conditions as influenced by geological processes, construction activity, and site use. VARYING OR UNEXPECTED CONDITIONS: Should any site or subsurface conditions be encountered that are different from those described in this report or encountered at the test locations, Stantec Consulting Services, Inc. must be notified immediately to assess if the varying or unexpected conditions are substantial and if reassessments of the report conclusions or recommendations are required. Stantec Consulting Services, Inc. will not be responsible to any party for damages incurred as a result of failing to notify Stantec Consulting Services, Inc. that differing site or sub-surface conditions are present upon becoming aware of such conditions. PLANNING, DESIGN, OR CONSTRUCTION: Development or design plans and specifications should be reviewed by Stantec Consulting Services, Inc., sufficiently ahead of initiating the next project stage (property acquisition, tender, construction, etc), to confirm that this report completely addresses the elaborated project specifics and that the contents of this report have been properly interpreted. Specialty quality assurance services (field observations and testing) during construction are a necessary part of the evaluation of sub-subsurface conditions and site preparation works. Site work relating to the recommendations included in this report should only be carried out in the presence of a qualified geotechnical engineer; Stantec Consulting Services, Inc. cannot be responsible for site work carried out without being present. APPENDIX B 10.2 APPENDIX B Figures: Vicinity Map Site Plans Rockery Diagram SITE N VICINITY MAP FIGURE 1 11130 NE 33rd Place, Suite 200 Bellevue, WA 98004 (425) 869-9448 (425) 869-1190 (Fax) www.stantec.com Project Location Renton WASHINGTON Thunder Hills Creek Renton, Washington Dec., 2014 2002003607 SITE PLAN FIGURE 2 11130 NE 33rd Place, Suite 200 Bellevue, WA 98004 (425) 869-9448 (425) 869-1190 (Fax) www.stantec.com Approximate Boring Location Approximate Boring Location (P&EE) B-1 PB-1 Thunder Hills Creek Renton, Washington Oct., 2016 2002003611VVN PB-1 B-3 B-4 PB-2 B-1 PB-5 PB-3 PB-4 B-2 New Rock Buttress New Rock Buttress Rockery Wall No. 1 Rockery Wall No. 1 Rockery Wall No. 2 SITE PLAN FIGURE 3 11130 NE 33rd Place, Suite 200 Bellevue, WA 98004 (425) 869-9448 (425) 869-1190 (Fax) www.stantec.com Approximate Hand Boring LocationHB-1 Thunder Hills Creek Renton, Washington Oct., 2016 2002003611VVN HB-1 Rockery Wall No. 2 Rockery Wall No. 3 SITE PLAN FIGURE 4 11130 NE 33rd Place, Suite 200 Bellevue, WA 98004 (425) 869-9448 (425) 869-1190 (Fax) www.stantec.com Thunder Hills Creek Renton, Washington Oct., 2016 2002003611VVN HB-2 HB-3 Approximate Hand Boring LocationHB-1 Rockery Wall No. 4 Rockery Wall No. 5 SITE PLAN FIGURE 5 11130 NE 33rd Place, Suite 200 Bellevue, WA 98004 (425) 869-9448 (425) 869-1190 (Fax) www.stantec.com Thunder Hills Creek Renton, Washington Oct., 2016 2002003611VVN HB-4 HB-5 Approximate Hand Boring LocationHB-1 Rockery Wall No. 6 Possible Wall SITE PLAN FIGURE 6 11130 NE 33rd Place, Suite 200 Bellevue, WA 98004 (425) 869-9448 (425) 869-1190 (Fax) www.stantec.com Thunder Hills Creek Renton, Washington Oct., 2016 2002003611VVN ROCKERY DIAGRAM FIGURE 7 11130 NE 33rd Place, Suite 200 Bellevue, WA 98004 (425) 869-9448 (425) 869-1190 (Fax) www.stantec.com 1 Max. 2 Min. Medium Dense or Firmer Native Soils Minimum 12” 4” Diameter Perforated PVC Pipe 2-4” Quarry Rock Min. 1.5’ Max. 3’ 1 6 Max. 10’ Thunder Hills Sewer Interceptor October, 2016 2002003611 APPENDIX C Boring Logs & Design Spreadsheets Vegetation/Topsoil SM; Medium dense to dense, silty-sand with variable amounts of gravel and debris, dark yellowish brown to grayish brown, moist to very moist. (Fill) ML; Stiff to very stiff, silt with variable amounts of sand, trace gravel, trace debris, trace woody debris, grayish brown to olive gray, moist to very moist. (Fill) ML; Stiff, silt with variable amounts of sand, trace gravel, trace woody debris, olive gray, moist. (Highly Weathered Renton Formation) SM; Medium dense, silty-sand, tan to yellow clasts of highly weathered sandstone, moist. (Renton Formation - Slightly Weathered) Borehole terminated at 25 feet. SM ML ML SM 7 6 4 2 16 17 3 3 3 7 11 12 2 4 3 3 4 6 2 3 5 5 4 7 INITIAL DTW (ft):Not Encountered WELL CASING DIA. (in):--- STARTED B-1 EXCAVATION COMPANY:CN EQUIPMENT:Limited Access DEPTH (ft):25.0 BORING NO.: SAMPLING EQUIPMENT:Split Spoon CHECKED BY:GS Time &Depth(feet)5 10 15 20 25 PROJECT NUMBER:2002003607 PROJECT:Thunder Hills Interceptor STATIC DTW (ft):Not Encountered LONG:LAT:COMPLETED:10/17/14 10/17/14 LOGGED BY:PH GROUND ELEV (ft):TOC ELEV (ft): LOCATION:Renton, WA Description NORTHING (ft):EASTING (ft): PAGE 1 OF 1 USCSGraphicLogMETHOD:HSA SIZE:6 WELL DEPTH (ft):--- EXCAVATION / INSTALLATION:GEO FORM 304 THUNDER HILLS.GPJ STANTEC ENVIRO TEMPLATE 010509.GDT 2/12/15MeasuredRecov.(feet)Depth(feet)5 10 15 20 25BlowCountSampleHeadspacePID(units)Time Sample ID Topsoil/Vegetation SM; Medium dense, silty-sand with variable amounts of gravel, trace debris, yellowish brown, moist. (Fill) SM; Dense, silty-sand with variable amounts of gravel, sandstone remnants at 8.5-9 feet, yellowish brown to grayish brown, moist. (Glacial Till) Borehole terminated at 9 feet. SM SM 2 3 9 10 15 11 5 14 19 16 17 22 INITIAL DTW (ft):Not Encountered WELL CASING DIA. (in):--- STARTED B-2 EXCAVATION COMPANY:CN EQUIPMENT:Limited Access DEPTH (ft):9.0 BORING NO.: SAMPLING EQUIPMENT:Split Spoon CHECKED BY:GS Time &Depth(feet)5 10 PROJECT NUMBER:2002003607 PROJECT:Thunder Hills Interceptor STATIC DTW (ft):Not Encountered LONG:LAT:COMPLETED:10/20/14 10/20/14 LOGGED BY:PH GROUND ELEV (ft):TOC ELEV (ft): LOCATION:Renton, WA Description NORTHING (ft):EASTING (ft): PAGE 1 OF 1 USCSGraphicLogMETHOD:HSA SIZE:6 WELL DEPTH (ft):--- EXCAVATION / INSTALLATION:GEO FORM 304 THUNDER HILLS.GPJ STANTEC ENVIRO TEMPLATE 010509.GDT 2/12/15MeasuredRecov.(feet)Depth(feet)5 10BlowCountSampleHeadspacePID(units)Time Sample ID Topsoil/Vegetation SM; Medium dense, silty-sand with variable amounts of gravel, trace debris, yellowish brown, moist. (Fill) SM; Dense, silty-sand with variable amounts of gravel, yellowish brown to grayish brown, moist. (Glacial Till) Borehole terminated at 9 feet. SM SM 2 3 5 10 11 10 8 14 15 18 20 22 INITIAL DTW (ft):Not Encountered WELL CASING DIA. (in):--- STARTED B-3 EXCAVATION COMPANY:CN EQUIPMENT:Limited Access DEPTH (ft):9.0 BORING NO.: SAMPLING EQUIPMENT:Split Spoon CHECKED BY:GS Time &Depth(feet)5 10 PROJECT NUMBER:2002003607 PROJECT:Thunder Hills Interceptor STATIC DTW (ft):Not Encountered LONG:LAT:COMPLETED:10/20/14 10/20/14 LOGGED BY:PH GROUND ELEV (ft):TOC ELEV (ft): LOCATION:Renton, WA Description NORTHING (ft):EASTING (ft): PAGE 1 OF 1 USCSGraphicLogMETHOD:HSA SIZE:6 WELL DEPTH (ft):--- EXCAVATION / INSTALLATION:GEO FORM 304 THUNDER HILLS.GPJ STANTEC ENVIRO TEMPLATE 010509.GDT 2/12/15MeasuredRecov.(feet)Depth(feet)5 10BlowCountSampleHeadspacePID(units)Time Sample ID Quarry rock SM; Loose to medium dense, silty-sand with variable amounts of gravel, trace debris, yellowish brown, moist to wet. (Fill) SM; Dense to hard, slightly weathered sandstone, yellowish brown to tan, moist. (Renton Formation) Borehole terminated at 6 feet. SM SM 2 5 4 8 12 11 50 INITIAL DTW (ft):Not Encountered WELL CASING DIA. (in):--- STARTED B-4 EXCAVATION COMPANY:CN EQUIPMENT:Limited Access DEPTH (ft):5.0 BORING NO.: SAMPLING EQUIPMENT:Split Spoon CHECKED BY:GS Time &Depth(feet)5 PROJECT NUMBER:2002003607 PROJECT:Thunder Hills Interceptor STATIC DTW (ft):Not Encountered LONG:LAT:COMPLETED:10/20/14 10/20/14 LOGGED BY:PH GROUND ELEV (ft):TOC ELEV (ft): LOCATION:Renton, WA Description NORTHING (ft):EASTING (ft): PAGE 1 OF 1 USCSGraphicLogMETHOD:HSA SIZE:6 WELL DEPTH (ft):--- EXCAVATION / INSTALLATION:GEO FORM 304 THUNDER HILLS.GPJ STANTEC ENVIRO TEMPLATE 010509.GDT 2/12/15MeasuredRecov.(feet)Depth(feet)5BlowCountSampleHeadspacePID(units)Time Sample ID ROCKERY DESIGN Job Name Job No. Designer Date This spreadsheet calculates: FS Overturning 2 Typically at least 2 FS Sliding 1.8 Typically at least 1.8 (includes FS for Coefficient of Friction) Converted to radians Total Height (H) = 5 ft Internal Angle of Friction of Retained Soil (phi)= 36 deg 0.63 rad Moist Unit Weight of Retained Soil (pcf) = 120 pcf br/H 0.5 Diameter of Base Rock (br) = 2.5 ft x2 = H/batter 0.833 Diameter of Top Rock (tr) = 2 ft x3 = H+tr-br+tiny 0.333 Batter of Rockery Face (s1) = 6 V to 1H Soil/ Wall Friction Angle (delta) = 20 deg 0.35 rad Backslope Angle (alpha)= 22 deg 0.38 rad Surcharge (q)= 0 psf Internal Angle of Friction of Subgrade Soil (phi2)= 36 deg 0.63 rad Rock Unit Weight = 155 pcf Percent Face Rock = 70% sin^2(beta+phi) 0.591 Back of Wall Angle from Horizontal (beta)= 93.8 deg Back of Rockery slope (s2) = 15.0 V to 1H 1.64 rad sin^2(beta) 0.996 Active Earth Pressure Coefficient (Ka) = 0.282 sin(beta-delta) 0.960 Horiz Distance of Rockery Centroid From Toe (x)=1.54 ft SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha) 0.232 Horiz Dist Between Toe and Back of Rockery at H 2.61 ft (1+root(G25))^2 2.194 Weight of Rockery (Wn)=1221 lb/ft (I21)(I22)(I24) 2.098 Horiz Component of Active Soil Load =0.960 Vert Component of Active Soil Load =0.279 Pa =423 lb/ft Pah =406 lb/ft Pav = 118 lb/ft Surcharge Load on Rockery =0 lb/ft Horiz Component of Surcharge Load on Rockery =0 lb/ft 90 deg 1.57 rad Equivalent Fluid Pressure (ap) 34 pcf Resisting OT Mom 1883 Factor of Safety for Overturning =2.78 OK Driving OT Mom 676 Factor of Safety for Sliding =2.39 OK Resisting Slid F 972 Driving Slid F 406 Wn = (Rock Unit Weight)(Percent Face Rock)(H)(br+tr)/2 Ka = SIN^2(beta+phi) SIN^2(beta)SIN(beta-delta)(1+SQRT(SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha))^2 ap = (Active Pressure)(Unit Weight of Soil) Pb = (ap)(H)+(Ka)(q) Pa = 0.5(Ka)(Weight of soil)(H^2) Surcharge Load on Rockery = q(Ka)(H) x = (H/2)/s+(br+tr)/4 Horiz and Vert Components of Active Soil Loads: Horiz = cos(90+delta-beta) Vert = absolute value of sin(90+delta-beta) Resisting Overturning Moment = (Rockery Weight)(Horiz Dist of Centroid from Toe)+(Pav)(Horiz Dist to Back of Rockery at H/3) Driving Overturning Moment = (Pah)(H/3)+(Horiz Component of Surcharge Load on Rockery)(H/2) Factor of Safety Against Overturning = Resisting Moment / Driving Moment Resisting Sliding Force = (Rockery Weight)(tan phi2) Driving Sliding Force = Pah+(Horiz Component of Surcharge Load on Rockery) Factor of Safety Against Sliding = Resisting Force / Driving Force Thunder Hills 2002003611 PH/SC 10/16/2016 ROCKERY DESIGN Job Name Job No. Designer Date This spreadsheet calculates: FS Overturning 2 Typically at least 2 FS Sliding 1.8 Typically at least 1.8 (includes FS for Coefficient of Friction) Converted to radians Total Height (H) = 5 ft Internal Angle of Friction of Retained Soil (phi)= 36 deg 0.63 rad Moist Unit Weight of Retained Soil (pcf) = 120 pcf br/H 0.4 Diameter of Base Rock (br) = 2 ft x2 = H/batter 0.833 Diameter of Top Rock (tr) = 1.5 ft x3 = H+tr-br+tiny 0.333 Batter of Rockery Face (s1) = 6 V to 1H Soil/ Wall Friction Angle (delta) = 20 deg 0.35 rad Backslope Angle (alpha)= 11 deg 0.19 rad Surcharge (q)= 0 psf Internal Angle of Friction of Subgrade Soil (phi2)= 36 deg 0.63 rad Rock Unit Weight = 155 pcf Percent Face Rock = 70% sin^2(beta+phi) 0.591 Back of Wall Angle from Horizontal (beta)= 93.8 deg Back of Rockery slope (s2) = 15.0 V to 1H 1.64 rad sin^2(beta) 0.996 Active Earth Pressure Coefficient (Ka) = 0.237 sin(beta-delta) 0.960 Horiz Distance of Rockery Centroid From Toe (x)=1.29 ft SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha) 0.377 Horiz Dist Between Toe and Back of Rockery at H 2.11 ft (1+root(G25))^2 2.605 Weight of Rockery (Wn)=949 lb/ft (I21)(I22)(I24) 2.491 Horiz Component of Active Soil Load =0.960 Vert Component of Active Soil Load =0.279 Pa =356 lb/ft Pah =342 lb/ft Pav = 99 lb/ft Surcharge Load on Rockery =0 lb/ft Horiz Component of Surcharge Load on Rockery =0 lb/ft 90 deg 1.57 rad Equivalent Fluid Pressure (ap) 28 pcf Resisting OT Mom 1227 Factor of Safety for Overturning =2.15 OK Driving OT Mom 570 Factor of Safety for Sliding =2.23 OK Resisting Slid F 761 Driving Slid F 342 Wn = (Rock Unit Weight)(Percent Face Rock)(H)(br+tr)/2 Ka = SIN^2(beta+phi) SIN^2(beta)SIN(beta-delta)(1+SQRT(SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha))^2 ap = (Active Pressure)(Unit Weight of Soil) Pb = (ap)(H)+(Ka)(q) Pa = 0.5(Ka)(Weight of soil)(H^2) Surcharge Load on Rockery = q(Ka)(H) x = (H/2)/s+(br+tr)/4 Horiz and Vert Components of Active Soil Loads: Horiz = cos(90+delta-beta) Vert = absolute value of sin(90+delta-beta) Resisting Overturning Moment = (Rockery Weight)(Horiz Dist of Centroid from Toe)+(Pav)(Horiz Dist to Back of Rockery at H/3) Driving Overturning Moment = (Pah)(H/3)+(Horiz Component of Surcharge Load on Rockery)(H/2) Factor of Safety Against Overturning = Resisting Moment / Driving Moment Resisting Sliding Force = (Rockery Weight)(tan phi2) Driving Sliding Force = Pah+(Horiz Component of Surcharge Load on Rockery) Factor of Safety Against Sliding = Resisting Force / Driving Force Thunder Hills 2002003611 PH/SC 10/16/2016 ROCKERY DESIGN Job Name Job No. Designer Date This spreadsheet calculates: FS Overturning 2 Typically at least 2 FS Sliding 1.8 Typically at least 1.8 (includes FS for Coefficient of Friction) Converted to radians Total Height (H) = 6 ft Internal Angle of Friction of Retained Soil (phi)= 36 deg 0.63 rad Moist Unit Weight of Retained Soil (pcf) = 120 pcf br/H 0.5 Diameter of Base Rock (br) = 3 ft x2 = H/batter 1.000 Diameter of Top Rock (tr) = 2 ft x3 = H+tr-br+tiny 0.000 Batter of Rockery Face (s1) = 6 V to 1H Soil/ Wall Friction Angle (delta) = 20 deg 0.35 rad Backslope Angle (alpha)= 22 deg 0.38 rad Surcharge (q)= 0 psf Internal Angle of Friction of Subgrade Soil (phi2)= 36 deg 0.63 rad Rock Unit Weight = 155 pcf Percent Face Rock = 70% sin^2(beta+phi) 0.656 Back of Wall Angle from Horizontal (beta)= 90.0 deg Back of Rockery slope (s2) = ######## V to 1H 1.57 rad sin^2(beta) 1.000 Active Earth Pressure Coefficient (Ka) = 0.319 sin(beta-delta) 0.939 Horiz Distance of Rockery Centroid From Toe (x)=1.75 ft SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha) 0.230 Horiz Dist Between Toe and Back of Rockery at H 3.00 ft (1+root(G25))^2 2.189 Weight of Rockery (Wn)=1628 lb/ft (I21)(I22)(I24) 2.057 Horiz Component of Active Soil Load =0.940 Vert Component of Active Soil Load =0.342 Pa =689 lb/ft Pah =647 lb/ft Pav = 235 lb/ft Surcharge Load on Rockery =0 lb/ft Horiz Component of Surcharge Load on Rockery =0 lb/ft 90 deg 1.57 rad Equivalent Fluid Pressure (ap) 38 pcf Resisting OT Mom 2849 Factor of Safety for Overturning =2.20 OK Driving OT Mom 1294 Factor of Safety for Sliding =2.09 OK Resisting Slid F 1353 Driving Slid F 647 Wn = (Rock Unit Weight)(Percent Face Rock)(H)(br+tr)/2 Ka = SIN^2(beta+phi) SIN^2(beta)SIN(beta-delta)(1+SQRT(SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha))^2 ap = (Active Pressure)(Unit Weight of Soil) Pb = (ap)(H)+(Ka)(q) Pa = 0.5(Ka)(Weight of soil)(H^2) Surcharge Load on Rockery = q(Ka)(H) x = (H/2)/s+(br+tr)/4 Horiz and Vert Components of Active Soil Loads: Horiz = cos(90+delta-beta) Vert = absolute value of sin(90+delta-beta) Resisting Overturning Moment = (Rockery Weight)(Horiz Dist of Centroid from Toe)+(Pav)(Horiz Dist to Back of Rockery at H/3) Driving Overturning Moment = (Pah)(H/3)+(Horiz Component of Surcharge Load on Rockery)(H/2) Factor of Safety Against Overturning = Resisting Moment / Driving Moment Resisting Sliding Force = (Rockery Weight)(tan phi2) Driving Sliding Force = Pah+(Horiz Component of Surcharge Load on Rockery) Factor of Safety Against Sliding = Resisting Force / Driving Force Thunder Hills 2002003611 PH/SC 10/16/2016 ROCKERY DESIGN Job Name Job No. Designer Date This spreadsheet calculates: FS Overturning 2 Typically at least 2 FS Sliding 1.8 Typically at least 1.8 (includes FS for Coefficient of Friction) Converted to radians Total Height (H) = 6 ft Internal Angle of Friction of Retained Soil (phi)= 36 deg 0.63 rad Moist Unit Weight of Retained Soil (pcf) = 120 pcf br/H 0.41666667 Diameter of Base Rock (br) = 2.5 ft x2 = H/batter 1.000 Diameter of Top Rock (tr) = 2 ft x3 = H+tr-br+tiny 0.500 Batter of Rockery Face (s1) = 6 V to 1H Soil/ Wall Friction Angle (delta) = 20 deg 0.35 rad Backslope Angle (alpha)= 11 deg 0.19 rad Surcharge (q)= 0 psf Internal Angle of Friction of Subgrade Soil (phi2)= 36 deg 0.63 rad Rock Unit Weight = 155 pcf Percent Face Rock = 70% sin^2(beta+phi) 0.575 Back of Wall Angle from Horizontal (beta)= 94.7 deg Back of Rockery slope (s2) = 12.0 V to 1H 1.65 rad sin^2(beta) 0.993 Active Earth Pressure Coefficient (Ka) = 0.230 sin(beta-delta) 0.965 Horiz Distance of Rockery Centroid From Toe (x)=1.63 ft SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha) 0.377 Horiz Dist Between Toe and Back of Rockery at H 2.67 ft (1+root(G25))^2 2.605 Weight of Rockery (Wn)=1465 lb/ft (I21)(I22)(I24) 2.496 Horiz Component of Active Soil Load =0.965 Vert Component of Active Soil Load =0.263 Pa =497 lb/ft Pah =480 lb/ft Pav = 131 lb/ft Surcharge Load on Rockery =0 lb/ft Horiz Component of Surcharge Load on Rockery =0 lb/ft 90 deg 1.57 rad Equivalent Fluid Pressure (ap) 28 pcf Resisting OT Mom 2381 Factor of Safety for Overturning =2.48 OK Driving OT Mom 960 Factor of Safety for Sliding =2.41 OK Resisting Slid F 1158 Driving Slid F 480 Wn = (Rock Unit Weight)(Percent Face Rock)(H)(br+tr)/2 Ka = SIN^2(beta+phi) SIN^2(beta)SIN(beta-delta)(1+SQRT(SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha))^2 ap = (Active Pressure)(Unit Weight of Soil) Pb = (ap)(H)+(Ka)(q) Pa = 0.5(Ka)(Weight of soil)(H^2) Surcharge Load on Rockery = q(Ka)(H) x = (H/2)/s+(br+tr)/4 Horiz and Vert Components of Active Soil Loads: Horiz = cos(90+delta-beta) Vert = absolute value of sin(90+delta-beta) Resisting Overturning Moment = (Rockery Weight)(Horiz Dist of Centroid from Toe)+(Pav)(Horiz Dist to Back of Rockery at H/3) Driving Overturning Moment = (Pah)(H/3)+(Horiz Component of Surcharge Load on Rockery)(H/2) Factor of Safety Against Overturning = Resisting Moment / Driving Moment Resisting Sliding Force = (Rockery Weight)(tan phi2) Driving Sliding Force = Pah+(Horiz Component of Surcharge Load on Rockery) Factor of Safety Against Sliding = Resisting Force / Driving Force Thunder Hills 2002003611 PH/SC 10/16/2016 ROCKERY DESIGN Job Name Job No. Designer Date This spreadsheet calculates: FS Overturning 2 Typically at least 2 FS Sliding 1.8 Typically at least 1.8 (includes FS for Coefficient of Friction) Converted to radians Total Height (H) = 7 ft Internal Angle of Friction of Retained Soil (phi)= 36 deg 0.63 rad Moist Unit Weight of Retained Soil (pcf) = 120 pcf br/H 0.5 Diameter of Base Rock (br) = 3.5 ft x2 = H/batter 1.167 Diameter of Top Rock (tr) = 2.5 ft x3 = H+tr-br+tiny 0.167 Batter of Rockery Face (s1) = 6 V to 1H Soil/ Wall Friction Angle (delta) = 20 deg 0.35 rad Backslope Angle (alpha)= 22 deg 0.38 rad Surcharge (q)= 0 psf Internal Angle of Friction of Subgrade Soil (phi2)= 36 deg 0.63 rad Rock Unit Weight = 155 pcf Percent Face Rock = 70% sin^2(beta+phi) 0.633 Back of Wall Angle from Horizontal (beta)= 91.3 deg Back of Rockery slope (s2) = 42.0 V to 1H 1.59 rad sin^2(beta) 0.999 Active Earth Pressure Coefficient (Ka) = 0.305 sin(beta-delta) 0.947 Horiz Distance of Rockery Centroid From Toe (x)=2.08 ft SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha) 0.230 Horiz Dist Between Toe and Back of Rockery at H 3.56 ft (1+root(G25))^2 2.190 Weight of Rockery (Wn)=2279 lb/ft (I21)(I22)(I24) 2.074 Horiz Component of Active Soil Load =0.948 Vert Component of Active Soil Load =0.319 Pa =897 lb/ft Pah =850 lb/ft Pav = 287 lb/ft Surcharge Load on Rockery =0 lb/ft Horiz Component of Surcharge Load on Rockery =0 lb/ft 90 deg 1.57 rad Equivalent Fluid Pressure (ap) 37 pcf Resisting OT Mom 4748 Factor of Safety for Overturning =2.39 OK Driving OT Mom 1984 Factor of Safety for Sliding =2.19 OK Resisting Slid F 1862 Driving Slid F 850 Wn = (Rock Unit Weight)(Percent Face Rock)(H)(br+tr)/2 Ka = SIN^2(beta+phi) SIN^2(beta)SIN(beta-delta)(1+SQRT(SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha))^2 ap = (Active Pressure)(Unit Weight of Soil) Pb = (ap)(H)+(Ka)(q) Pa = 0.5(Ka)(Weight of soil)(H^2) Surcharge Load on Rockery = q(Ka)(H) x = (H/2)/s+(br+tr)/4 Horiz and Vert Components of Active Soil Loads: Horiz = cos(90+delta-beta) Vert = absolute value of sin(90+delta-beta) Resisting Overturning Moment = (Rockery Weight)(Horiz Dist of Centroid from Toe)+(Pav)(Horiz Dist to Back of Rockery at H/3) Driving Overturning Moment = (Pah)(H/3)+(Horiz Component of Surcharge Load on Rockery)(H/2) Factor of Safety Against Overturning = Resisting Moment / Driving Moment Resisting Sliding Force = (Rockery Weight)(tan phi2) Driving Sliding Force = Pah+(Horiz Component of Surcharge Load on Rockery) Factor of Safety Against Sliding = Resisting Force / Driving Force Thunder Hills 2002003611 PH/SC 10/16/2016 ROCKERY DESIGN Job Name Job No. Designer Date This spreadsheet calculates: FS Overturning 2 Typically at least 2 FS Sliding 1.8 Typically at least 1.8 (includes FS for Coefficient of Friction) Converted to radians Total Height (H) = 7 ft Internal Angle of Friction of Retained Soil (phi)= 36 deg 0.63 rad Moist Unit Weight of Retained Soil (pcf) = 120 pcf br/H 0.42857143 Diameter of Base Rock (br) = 3 ft x2 = H/batter 1.167 Diameter of Top Rock (tr) = 2 ft x3 = H+tr-br+tiny 0.167 Batter of Rockery Face (s1) = 6 V to 1H Soil/ Wall Friction Angle (delta) = 20 deg 0.35 rad Backslope Angle (alpha)= 11 deg 0.19 rad Surcharge (q)= 0 psf Internal Angle of Friction of Subgrade Soil (phi2)= 36 deg 0.63 rad Rock Unit Weight = 155 pcf Percent Face Rock = 70% sin^2(beta+phi) 0.633 Back of Wall Angle from Horizontal (beta)= 91.3 deg Back of Rockery slope (s2) = 42.0 V to 1H 1.59 rad sin^2(beta) 0.999 Active Earth Pressure Coefficient (Ka) = 0.256 sin(beta-delta) 0.947 Horiz Distance of Rockery Centroid From Toe (x)=1.83 ft SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha) 0.378 Horiz Dist Between Toe and Back of Rockery at H 3.06 ft (1+root(G25))^2 2.608 Weight of Rockery (Wn)=1899 lb/ft (I21)(I22)(I24) 2.470 Horiz Component of Active Soil Load =0.948 Vert Component of Active Soil Load =0.319 Pa =753 lb/ft Pah =714 lb/ft Pav = 241 lb/ft Surcharge Load on Rockery =0 lb/ft Horiz Component of Surcharge Load on Rockery =0 lb/ft 90 deg 1.57 rad Equivalent Fluid Pressure (ap) 31 pcf Resisting OT Mom 3482 Factor of Safety for Overturning =2.09 OK Driving OT Mom 1666 Factor of Safety for Sliding =2.18 OK Resisting Slid F 1553 Driving Slid F 714 Wn = (Rock Unit Weight)(Percent Face Rock)(H)(br+tr)/2 Ka = SIN^2(beta+phi) SIN^2(beta)SIN(beta-delta)(1+SQRT(SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha))^2 ap = (Active Pressure)(Unit Weight of Soil) Pb = (ap)(H)+(Ka)(q) Pa = 0.5(Ka)(Weight of soil)(H^2) Surcharge Load on Rockery = q(Ka)(H) x = (H/2)/s+(br+tr)/4 Horiz and Vert Components of Active Soil Loads: Horiz = cos(90+delta-beta) Vert = absolute value of sin(90+delta-beta) Resisting Overturning Moment = (Rockery Weight)(Horiz Dist of Centroid from Toe)+(Pav)(Horiz Dist to Back of Rockery at H/3) Driving Overturning Moment = (Pah)(H/3)+(Horiz Component of Surcharge Load on Rockery)(H/2) Factor of Safety Against Overturning = Resisting Moment / Driving Moment Resisting Sliding Force = (Rockery Weight)(tan phi2) Driving Sliding Force = Pah+(Horiz Component of Surcharge Load on Rockery) Factor of Safety Against Sliding = Resisting Force / Driving Force Thunder Hills 2002003611 PH/SC 10/16/2016 ROCKERY DESIGN Job Name Job No. Designer Date This spreadsheet calculates: FS Overturning 2 Typically at least 2 FS Sliding 1.8 Typically at least 1.8 (includes FS for Coefficient of Friction) Converted to radians Total Height (H) = 8 ft Internal Angle of Friction of Retained Soil (phi)= 36 deg 0.63 rad Moist Unit Weight of Retained Soil (pcf) = 120 pcf br/H 0.5 Diameter of Base Rock (br) = 4 ft x2 = H/batter 1.333 Diameter of Top Rock (tr) = 2.5 ft x3 = H+tr-br+tiny -0.167 Batter of Rockery Face (s1) = 6 V to 1H Soil/ Wall Friction Angle (delta) = 20 deg 0.35 rad Backslope Angle (alpha)= 22 deg 0.38 rad Surcharge (q)= 0 psf Internal Angle of Friction of Subgrade Soil (phi2)= 36 deg 0.63 rad Rock Unit Weight = 155 pcf Percent Face Rock = 70% sin^2(beta+phi) 0.675 Back of Wall Angle from Horizontal (beta)= 88.8 deg Back of Rockery slope (s2) = -48.0 V to 1H 1.55 rad sin^2(beta) 1.000 Active Earth Pressure Coefficient (Ka) = 0.331 sin(beta-delta) 0.932 Horiz Distance of Rockery Centroid From Toe (x)=2.29 ft SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha) 0.230 Horiz Dist Between Toe and Back of Rockery at H 3.94 ft (1+root(G25))^2 2.189 Weight of Rockery (Wn)=2821 lb/ft (I21)(I22)(I24) 2.039 Horiz Component of Active Soil Load =0.932 Vert Component of Active Soil Load =0.361 Pa =1271 lb/ft Pah =1185 lb/ft Pav = 459 lb/ft Surcharge Load on Rockery =0 lb/ft Horiz Component of Surcharge Load on Rockery =0 lb/ft 90 deg 1.57 rad Equivalent Fluid Pressure (ap) 40 pcf Resisting OT Mom 6466 Factor of Safety for Overturning =2.05 OK Driving OT Mom 3161 Factor of Safety for Sliding =2.01 OK Resisting Slid F 2382 Driving Slid F 1185 Wn = (Rock Unit Weight)(Percent Face Rock)(H)(br+tr)/2 Ka = SIN^2(beta+phi) SIN^2(beta)SIN(beta-delta)(1+SQRT(SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha))^2 ap = (Active Pressure)(Unit Weight of Soil) Pb = (ap)(H)+(Ka)(q) Pa = 0.5(Ka)(Weight of soil)(H^2) Surcharge Load on Rockery = q(Ka)(H) x = (H/2)/s+(br+tr)/4 Horiz and Vert Components of Active Soil Loads: Horiz = cos(90+delta-beta) Vert = absolute value of sin(90+delta-beta) Resisting Overturning Moment = (Rockery Weight)(Horiz Dist of Centroid from Toe)+(Pav)(Horiz Dist to Back of Rockery at H/3) Driving Overturning Moment = (Pah)(H/3)+(Horiz Component of Surcharge Load on Rockery)(H/2) Factor of Safety Against Overturning = Resisting Moment / Driving Moment Resisting Sliding Force = (Rockery Weight)(tan phi2) Driving Sliding Force = Pah+(Horiz Component of Surcharge Load on Rockery) Factor of Safety Against Sliding = Resisting Force / Driving Force Thunder Hills 2002003611 PH/SC 10/16/2016 ROCKERY DESIGN Job Name Job No. Designer Date This spreadsheet calculates: FS Overturning 2 Typically at least 2 FS Sliding 1.8 Typically at least 1.8 (includes FS for Coefficient of Friction) Converted to radians Total Height (H) = 8 ft Internal Angle of Friction of Retained Soil (phi)= 36 deg 0.63 rad Moist Unit Weight of Retained Soil (pcf) = 120 pcf br/H 0.4375 Diameter of Base Rock (br) = 3.5 ft x2 = H/batter 1.333 Diameter of Top Rock (tr) = 2.5 ft x3 = H+tr-br+tiny 0.333 Batter of Rockery Face (s1) = 6 V to 1H Soil/ Wall Friction Angle (delta) = 20 deg 0.35 rad Backslope Angle (alpha)= 11 deg 0.19 rad Surcharge (q)= 0 psf Internal Angle of Friction of Subgrade Soil (phi2)= 36 deg 0.63 rad Rock Unit Weight = 155 pcf Percent Face Rock = 70% sin^2(beta+phi) 0.615 Back of Wall Angle from Horizontal (beta)= 92.3 deg Back of Rockery slope (s2) = 24.0 V to 1H 1.61 rad sin^2(beta) 0.998 Active Earth Pressure Coefficient (Ka) = 0.248 sin(beta-delta) 0.953 Horiz Distance of Rockery Centroid From Toe (x)=2.17 ft SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha) 0.378 Horiz Dist Between Toe and Back of Rockery at H 3.61 ft (1+root(G25))^2 2.606 Weight of Rockery (Wn)=2604 lb/ft (I21)(I22)(I24) 2.480 Horiz Component of Active Soil Load =0.953 Vert Component of Active Soil Load =0.302 Pa =953 lb/ft Pah =909 lb/ft Pav = 288 lb/ft Surcharge Load on Rockery =0 lb/ft Horiz Component of Surcharge Load on Rockery =0 lb/ft 90 deg 1.57 rad Equivalent Fluid Pressure (ap) 30 pcf Resisting OT Mom 5643 Factor of Safety for Overturning =2.33 OK Driving OT Mom 2423 Factor of Safety for Sliding =2.31 OK Resisting Slid F 2100 Driving Slid F 909 Wn = (Rock Unit Weight)(Percent Face Rock)(H)(br+tr)/2 Ka = SIN^2(beta+phi) SIN^2(beta)SIN(beta-delta)(1+SQRT(SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha))^2 ap = (Active Pressure)(Unit Weight of Soil) Pb = (ap)(H)+(Ka)(q) Pa = 0.5(Ka)(Weight of soil)(H^2) Surcharge Load on Rockery = q(Ka)(H) x = (H/2)/s+(br+tr)/4 Horiz and Vert Components of Active Soil Loads: Horiz = cos(90+delta-beta) Vert = absolute value of sin(90+delta-beta) Resisting Overturning Moment = (Rockery Weight)(Horiz Dist of Centroid from Toe)+(Pav)(Horiz Dist to Back of Rockery at H/3) Driving Overturning Moment = (Pah)(H/3)+(Horiz Component of Surcharge Load on Rockery)(H/2) Factor of Safety Against Overturning = Resisting Moment / Driving Moment Resisting Sliding Force = (Rockery Weight)(tan phi2) Driving Sliding Force = Pah+(Horiz Component of Surcharge Load on Rockery) Factor of Safety Against Sliding = Resisting Force / Driving Force Thunder Hills 2002003611 PH/SC 10/16/2016 ROCKERY DESIGN Job Name Job No. Designer Date This spreadsheet calculates: FS Overturning 2 Typically at least 2 FS Sliding 1.8 Typically at least 1.8 (includes FS for Coefficient of Friction) Converted to radians Total Height (H) = 9 ft Internal Angle of Friction of Retained Soil (phi)= 36 deg 0.63 rad Moist Unit Weight of Retained Soil (pcf) = 120 pcf br/H 0.44444444 Diameter of Base Rock (br) = 4 ft x2 = H/batter 1.500 Diameter of Top Rock (tr) = 3 ft x3 = H+tr-br+tiny 0.500 Batter of Rockery Face (s1) = 6 V to 1H Soil/ Wall Friction Angle (delta) = 20 deg 0.35 rad Backslope Angle (alpha)= 22 deg 0.38 rad Surcharge (q)= 0 psf Internal Angle of Friction of Subgrade Soil (phi2)= 36 deg 0.63 rad Rock Unit Weight = 155 pcf Percent Face Rock = 70% sin^2(beta+phi) 0.602 Back of Wall Angle from Horizontal (beta)= 93.1 deg Back of Rockery slope (s2) = 18.0 V to 1H 1.63 rad sin^2(beta) 0.997 Active Earth Pressure Coefficient (Ka) = 0.288 sin(beta-delta) 0.957 Horiz Distance of Rockery Centroid From Toe (x)=2.50 ft SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha) 0.231 Horiz Dist Between Toe and Back of Rockery at H 4.17 ft (1+root(G25))^2 2.193 Weight of Rockery (Wn)=3418 lb/ft (I21)(I22)(I24) 2.093 Horiz Component of Active Soil Load =0.957 Vert Component of Active Soil Load =0.289 Pa =1398 lb/ft Pah =1338 lb/ft Pav = 404 lb/ft Surcharge Load on Rockery =0 lb/ft Horiz Component of Surcharge Load on Rockery =0 lb/ft 90 deg 1.57 rad Equivalent Fluid Pressure (ap) 35 pcf Resisting OT Mom 8546 Factor of Safety for Overturning =2.13 OK Driving OT Mom 4015 Factor of Safety for Sliding =2.07 OK Resisting Slid F 2775 Driving Slid F 1338 Wn = (Rock Unit Weight)(Percent Face Rock)(H)(br+tr)/2 Ka = SIN^2(beta+phi) SIN^2(beta)SIN(beta-delta)(1+SQRT(SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha))^2 ap = (Active Pressure)(Unit Weight of Soil) Pb = (ap)(H)+(Ka)(q) Pa = 0.5(Ka)(Weight of soil)(H^2) Surcharge Load on Rockery = q(Ka)(H) x = (H/2)/s+(br+tr)/4 Horiz and Vert Components of Active Soil Loads: Horiz = cos(90+delta-beta) Vert = absolute value of sin(90+delta-beta) Resisting Overturning Moment = (Rockery Weight)(Horiz Dist of Centroid from Toe)+(Pav)(Horiz Dist to Back of Rockery at H/3) Driving Overturning Moment = (Pah)(H/3)+(Horiz Component of Surcharge Load on Rockery)(H/2) Factor of Safety Against Overturning = Resisting Moment / Driving Moment Resisting Sliding Force = (Rockery Weight)(tan phi2) Driving Sliding Force = Pah+(Horiz Component of Surcharge Load on Rockery) Factor of Safety Against Sliding = Resisting Force / Driving Force Thunder Hills 2002003611 PH/SC 10/16/2016 ROCKERY DESIGN Job Name Job No. Designer Date This spreadsheet calculates: FS Overturning 2 Typically at least 2 FS Sliding 1.8 Typically at least 1.8 (includes FS for Coefficient of Friction) Converted to radians Total Height (H) = 9 ft Internal Angle of Friction of Retained Soil (phi)= 36 deg 0.63 rad Moist Unit Weight of Retained Soil (pcf) = 120 pcf br/H 0.38888889 Diameter of Base Rock (br) = 3.5 ft x2 = H/batter 1.500 Diameter of Top Rock (tr) = 3 ft x3 = H+tr-br+tiny 1.000 Batter of Rockery Face (s1) = 6 V to 1H Soil/ Wall Friction Angle (delta) = 20 deg 0.35 rad Backslope Angle (alpha)= 11 deg 0.19 rad Surcharge (q)= 0 psf Internal Angle of Friction of Subgrade Soil (phi2)= 36 deg 0.63 rad Rock Unit Weight = 155 pcf Percent Face Rock = 70% sin^2(beta+phi) 0.547 Back of Wall Angle from Horizontal (beta)= 96.3 deg Back of Rockery slope (s2) = 9.0 V to 1H 1.68 rad sin^2(beta) 0.988 Active Earth Pressure Coefficient (Ka) = 0.219 sin(beta-delta) 0.972 Horiz Distance of Rockery Centroid From Toe (x)=2.38 ft SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha) 0.377 Horiz Dist Between Toe and Back of Rockery at H 3.83 ft (1+root(G25))^2 2.606 Weight of Rockery (Wn)=3174 lb/ft (I21)(I22)(I24) 2.501 Horiz Component of Active Soil Load =0.972 Vert Component of Active Soil Load =0.236 Pa =1064 lb/ft Pah =1034 lb/ft Pav = 251 lb/ft Surcharge Load on Rockery =0 lb/ft Horiz Component of Surcharge Load on Rockery =0 lb/ft 90 deg 1.57 rad Equivalent Fluid Pressure (ap) 26 pcf Resisting OT Mom 7538 Factor of Safety for Overturning =2.43 OK Driving OT Mom 3101 Factor of Safety for Sliding =2.41 OK Resisting Slid F 2486 Driving Slid F 1034 Wn = (Rock Unit Weight)(Percent Face Rock)(H)(br+tr)/2 Ka = SIN^2(beta+phi) SIN^2(beta)SIN(beta-delta)(1+SQRT(SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha))^2 ap = (Active Pressure)(Unit Weight of Soil) Pb = (ap)(H)+(Ka)(q) Pa = 0.5(Ka)(Weight of soil)(H^2) Surcharge Load on Rockery = q(Ka)(H) x = (H/2)/s+(br+tr)/4 Horiz and Vert Components of Active Soil Loads: Horiz = cos(90+delta-beta) Vert = absolute value of sin(90+delta-beta) Resisting Overturning Moment = (Rockery Weight)(Horiz Dist of Centroid from Toe)+(Pav)(Horiz Dist to Back of Rockery at H/3) Driving Overturning Moment = (Pah)(H/3)+(Horiz Component of Surcharge Load on Rockery)(H/2) Factor of Safety Against Overturning = Resisting Moment / Driving Moment Resisting Sliding Force = (Rockery Weight)(tan phi2) Driving Sliding Force = Pah+(Horiz Component of Surcharge Load on Rockery) Factor of Safety Against Sliding = Resisting Force / Driving Force Thunder Hills 2002003611 PH/SC 10/16/2016 ROCKERY DESIGN Job Name Job No. Designer Date This spreadsheet calculates: FS Overturning 2 Typically at least 2 FS Sliding 1.8 Typically at least 1.8 (includes FS for Coefficient of Friction) Converted to radians Total Height (H) = 10 ft Internal Angle of Friction of Retained Soil (phi)= 36 deg 0.63 rad Moist Unit Weight of Retained Soil (pcf) = 120 pcf br/H 0.45 Diameter of Base Rock (br) = 4.5 ft x2 = H/batter 1.667 Diameter of Top Rock (tr) = 3.5 ft x3 = H+tr-br+tiny 0.667 Batter of Rockery Face (s1) = 6 V to 1H Soil/ Wall Friction Angle (delta) = 20 deg 0.35 rad Backslope Angle (alpha)= 22 deg 0.38 rad Surcharge (q)= 0 psf Internal Angle of Friction of Subgrade Soil (phi2)= 36 deg 0.63 rad Rock Unit Weight = 155 pcf Percent Face Rock = 70% sin^2(beta+phi) 0.591 Back of Wall Angle from Horizontal (beta)= 93.8 deg Back of Rockery slope (s2) = 15.0 V to 1H 1.64 rad sin^2(beta) 0.996 Active Earth Pressure Coefficient (Ka) = 0.282 sin(beta-delta) 0.960 Horiz Distance of Rockery Centroid From Toe (x)=2.83 ft SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha) 0.232 Horiz Dist Between Toe and Back of Rockery at H 4.72 ft (1+root(G25))^2 2.194 Weight of Rockery (Wn)=4340 lb/ft (I21)(I22)(I24) 2.098 Horiz Component of Active Soil Load =0.960 Vert Component of Active Soil Load =0.279 Pa =1690 lb/ft Pah =1624 lb/ft Pav = 471 lb/ft Surcharge Load on Rockery =0 lb/ft Horiz Component of Surcharge Load on Rockery =0 lb/ft 90 deg 1.57 rad Equivalent Fluid Pressure (ap) 34 pcf Resisting OT Mom 12298 Factor of Safety for Overturning =2.27 OK Driving OT Mom 5412 Factor of Safety for Sliding =2.15 OK Resisting Slid F 3493 Driving Slid F 1624 Wn = (Rock Unit Weight)(Percent Face Rock)(H)(br+tr)/2 Ka = SIN^2(beta+phi) SIN^2(beta)SIN(beta-delta)(1+SQRT(SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha))^2 ap = (Active Pressure)(Unit Weight of Soil) Pb = (ap)(H)+(Ka)(q) Pa = 0.5(Ka)(Weight of soil)(H^2) Surcharge Load on Rockery = q(Ka)(H) x = (H/2)/s+(br+tr)/4 Horiz and Vert Components of Active Soil Loads: Horiz = cos(90+delta-beta) Vert = absolute value of sin(90+delta-beta) Resisting Overturning Moment = (Rockery Weight)(Horiz Dist of Centroid from Toe)+(Pav)(Horiz Dist to Back of Rockery at H/3) Driving Overturning Moment = (Pah)(H/3)+(Horiz Component of Surcharge Load on Rockery)(H/2) Factor of Safety Against Overturning = Resisting Moment / Driving Moment Resisting Sliding Force = (Rockery Weight)(tan phi2) Driving Sliding Force = Pah+(Horiz Component of Surcharge Load on Rockery) Factor of Safety Against Sliding = Resisting Force / Driving Force Thunder Hills 2002003611 PH/SC 10/16/2016 ROCKERY DESIGN Job Name Job No. Designer Date This spreadsheet calculates: FS Overturning 2 Typically at least 2 FS Sliding 1.8 Typically at least 1.8 (includes FS for Coefficient of Friction) Converted to radians Total Height (H) = 10 ft Internal Angle of Friction of Retained Soil (phi)= 36 deg 0.63 rad Moist Unit Weight of Retained Soil (pcf) = 120 pcf br/H 0.4 Diameter of Base Rock (br) = 4 ft x2 = H/batter 1.667 Diameter of Top Rock (tr) = 3 ft x3 = H+tr-br+tiny 0.667 Batter of Rockery Face (s1) = 6 V to 1H Soil/ Wall Friction Angle (delta) = 20 deg 0.35 rad Backslope Angle (alpha)= 11 deg 0.19 rad Surcharge (q)= 0 psf Internal Angle of Friction of Subgrade Soil (phi2)= 36 deg 0.63 rad Rock Unit Weight = 155 pcf Percent Face Rock = 70% sin^2(beta+phi) 0.591 Back of Wall Angle from Horizontal (beta)= 93.8 deg Back of Rockery slope (s2) = 15.0 V to 1H 1.64 rad sin^2(beta) 0.996 Active Earth Pressure Coefficient (Ka) = 0.237 sin(beta-delta) 0.960 Horiz Distance of Rockery Centroid From Toe (x)=2.58 ft SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha) 0.377 Horiz Dist Between Toe and Back of Rockery at H 4.22 ft (1+root(G25))^2 2.605 Weight of Rockery (Wn)=3798 lb/ft (I21)(I22)(I24) 2.491 Horiz Component of Active Soil Load =0.960 Vert Component of Active Soil Load =0.279 Pa =1424 lb/ft Pah =1368 lb/ft Pav = 397 lb/ft Surcharge Load on Rockery =0 lb/ft Horiz Component of Surcharge Load on Rockery =0 lb/ft 90 deg 1.57 rad Equivalent Fluid Pressure (ap) 28 pcf Resisting OT Mom 9811 Factor of Safety for Overturning =2.15 OK Driving OT Mom 4559 Factor of Safety for Sliding =2.23 OK Resisting Slid F 3045 Driving Slid F 1368 Wn = (Rock Unit Weight)(Percent Face Rock)(H)(br+tr)/2 Ka = SIN^2(beta+phi) SIN^2(beta)SIN(beta-delta)(1+SQRT(SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha))^2 ap = (Active Pressure)(Unit Weight of Soil) Pb = (ap)(H)+(Ka)(q) Pa = 0.5(Ka)(Weight of soil)(H^2) Surcharge Load on Rockery = q(Ka)(H) x = (H/2)/s+(br+tr)/4 Horiz and Vert Components of Active Soil Loads: Horiz = cos(90+delta-beta) Vert = absolute value of sin(90+delta-beta) Resisting Overturning Moment = (Rockery Weight)(Horiz Dist of Centroid from Toe)+(Pav)(Horiz Dist to Back of Rockery at H/3) Driving Overturning Moment = (Pah)(H/3)+(Horiz Component of Surcharge Load on Rockery)(H/2) Factor of Safety Against Overturning = Resisting Moment / Driving Moment Resisting Sliding Force = (Rockery Weight)(tan phi2) Driving Sliding Force = Pah+(Horiz Component of Surcharge Load on Rockery) Factor of Safety Against Sliding = Resisting Force / Driving Force Thunder Hills 2002003611 PH/SC 10/16/2016 ROCKERY DESIGN Job Name Job No. Designer Date This spreadsheet calculates: FS Overturning 2 Typically at least 2 FS Sliding 1.8 Typically at least 1.8 (includes FS for Coefficient of Friction) Converted to radians Total Height (H) = 11 ft Internal Angle of Friction of Retained Soil (phi)= 36 deg 0.63 rad Moist Unit Weight of Retained Soil (pcf) = 120 pcf br/H 0.45454545 Diameter of Base Rock (br) = 5 ft x2 = H/batter 1.833 Diameter of Top Rock (tr) = 3.5 ft x3 = H+tr-br+tiny 0.333 Batter of Rockery Face (s1) = 6 V to 1H Soil/ Wall Friction Angle (delta) = 20 deg 0.35 rad Backslope Angle (alpha)= 22 deg 0.38 rad Surcharge (q)= 0 psf Internal Angle of Friction of Subgrade Soil (phi2)= 36 deg 0.63 rad Rock Unit Weight = 155 pcf Percent Face Rock = 70% sin^2(beta+phi) 0.627 Back of Wall Angle from Horizontal (beta)= 91.7 deg Back of Rockery slope (s2) = 33.0 V to 1H 1.60 rad sin^2(beta) 0.999 Active Earth Pressure Coefficient (Ka) = 0.301 sin(beta-delta) 0.949 Horiz Distance of Rockery Centroid From Toe (x)=3.04 ft SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha) 0.230 Horiz Dist Between Toe and Back of Rockery at H 5.11 ft (1+root(G25))^2 2.191 Weight of Rockery (Wn)=5072 lb/ft (I21)(I22)(I24) 2.078 Horiz Component of Active Soil Load =0.950 Vert Component of Active Soil Load =0.313 Pa =2189 lb/ft Pah =2079 lb/ft Pav = 686 lb/ft Surcharge Load on Rockery =0 lb/ft Horiz Component of Surcharge Load on Rockery =0 lb/ft 90 deg 1.57 rad Equivalent Fluid Pressure (ap) 36 pcf Resisting OT Mom 15430 Factor of Safety for Overturning =2.02 OK Driving OT Mom 7622 Factor of Safety for Sliding =2.01 OK Resisting Slid F 4181 Driving Slid F 2079 Wn = (Rock Unit Weight)(Percent Face Rock)(H)(br+tr)/2 Ka = SIN^2(beta+phi) SIN^2(beta)SIN(beta-delta)(1+SQRT(SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha))^2 ap = (Active Pressure)(Unit Weight of Soil) Pb = (ap)(H)+(Ka)(q) Pa = 0.5(Ka)(Weight of soil)(H^2) Surcharge Load on Rockery = q(Ka)(H) x = (H/2)/s+(br+tr)/4 Horiz and Vert Components of Active Soil Loads: Horiz = cos(90+delta-beta) Vert = absolute value of sin(90+delta-beta) Resisting Overturning Moment = (Rockery Weight)(Horiz Dist of Centroid from Toe)+(Pav)(Horiz Dist to Back of Rockery at H/3) Driving Overturning Moment = (Pah)(H/3)+(Horiz Component of Surcharge Load on Rockery)(H/2) Factor of Safety Against Overturning = Resisting Moment / Driving Moment Resisting Sliding Force = (Rockery Weight)(tan phi2) Driving Sliding Force = Pah+(Horiz Component of Surcharge Load on Rockery) Factor of Safety Against Sliding = Resisting Force / Driving Force Thunder Hills 2002003611 PH/SC 10/16/2016 ROCKERY DESIGN Job Name Job No. Designer Date This spreadsheet calculates: FS Overturning 2 Typically at least 2 FS Sliding 1.8 Typically at least 1.8 (includes FS for Coefficient of Friction) Converted to radians Total Height (H) = 11 ft Internal Angle of Friction of Retained Soil (phi)= 36 deg 0.63 rad Moist Unit Weight of Retained Soil (pcf) = 120 pcf br/H 0.36363636 Diameter of Base Rock (br) = 4 ft x2 = H/batter 1.833 Diameter of Top Rock (tr) = 3.5 ft x3 = H+tr-br+tiny 1.333 Batter of Rockery Face (s1) = 6 V to 1H Soil/ Wall Friction Angle (delta) = 20 deg 0.35 rad Backslope Angle (alpha)= 11 deg 0.19 rad Surcharge (q)= 0 psf Internal Angle of Friction of Subgrade Soil (phi2)= 36 deg 0.63 rad Rock Unit Weight = 155 pcf Percent Face Rock = 70% sin^2(beta+phi) 0.538 Back of Wall Angle from Horizontal (beta)= 96.9 deg Back of Rockery slope (s2) = 8.2 V to 1H 1.69 rad sin^2(beta) 0.986 Active Earth Pressure Coefficient (Ka) = 0.215 sin(beta-delta) 0.974 Horiz Distance of Rockery Centroid From Toe (x)=2.79 ft SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha) 0.378 Horiz Dist Between Toe and Back of Rockery at H 4.44 ft (1+root(G25))^2 2.607 Weight of Rockery (Wn)=4476 lb/ft (I21)(I22)(I24) 2.502 Horiz Component of Active Soil Load =0.974 Vert Component of Active Soil Load =0.226 Pa =1560 lb/ft Pah =1519 lb/ft Pav = 353 lb/ft Surcharge Load on Rockery =0 lb/ft Horiz Component of Surcharge Load on Rockery =0 lb/ft 90 deg 1.57 rad Equivalent Fluid Pressure (ap) 26 pcf Resisting OT Mom 12495 Factor of Safety for Overturning =2.24 OK Driving OT Mom 5570 Factor of Safety for Sliding =2.31 OK Resisting Slid F 3506 Driving Slid F 1519 Wn = (Rock Unit Weight)(Percent Face Rock)(H)(br+tr)/2 Ka = SIN^2(beta+phi) SIN^2(beta)SIN(beta-delta)(1+SQRT(SIN(phi+delta)SIN(phi-alpha)/SIN(beta-delta)SIN(beta+alpha))^2 ap = (Active Pressure)(Unit Weight of Soil) Pb = (ap)(H)+(Ka)(q) Pa = 0.5(Ka)(Weight of soil)(H^2) Surcharge Load on Rockery = q(Ka)(H) x = (H/2)/s+(br+tr)/4 Horiz and Vert Components of Active Soil Loads: Horiz = cos(90+delta-beta) Vert = absolute value of sin(90+delta-beta) Resisting Overturning Moment = (Rockery Weight)(Horiz Dist of Centroid from Toe)+(Pav)(Horiz Dist to Back of Rockery at H/3) Driving Overturning Moment = (Pah)(H/3)+(Horiz Component of Surcharge Load on Rockery)(H/2) Factor of Safety Against Overturning = Resisting Moment / Driving Moment Resisting Sliding Force = (Rockery Weight)(tan phi2) Driving Sliding Force = Pah+(Horiz Component of Surcharge Load on Rockery) Factor of Safety Against Sliding = Resisting Force / Driving Force Thunder Hills 2002003611 PH/SC 10/16/2016