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HomeMy WebLinkAboutReport GeotechnicalSubgradeEvaluation final.pdf 1 Geotechnical Subgrade Report D Street NE Utility Improvements S. 277th Street to Auburn Way N. Auburn, Washington June 4, 2013 Terracon Project No. 81135017 Prepared for: City of Auburn Department of Public Works Auburn, Washington Prepared by: Terracon Consultants, Inc. Mountlake Terrace, Washington TABLE OF CONTENTS EXECUTIVE SUMMARY ............................................................................................................... i  1.0 INTRODUCTION ................................................................................................................... 1  2.0 PROJECT INFORMATION .................................................................................................... 1  2.1 Site Delineation .................................................................................................................. 1  2.2 Existing Site Usage ............................................................................................................ 2  2.3 Proposed Site Development ............................................................................................... 2  2.4 Scope of Work .................................................................................................................... 3  3.0 SITE SETTING ...................................................................................................................... 4  3.1 Regional Geography .......................................................................................................... 4  3.2 Regional Geology ............................................................................................................... 4  3.3 Regional Zoning ................................................................................................................. 4  4.0 SITE CONDITIONS ............................................................................................................... 5  4.1 Surface Features ................................................................................................................ 5  4.2 Soil Stratigraphy ................................................................................................................. 6  4.3 Groundwater Levels ........................................................................................................... 6  5.0 CONCLUSIONS AND RECOMMENDATIONS ...................................................................... 7  5.1 General Design Considerations ......................................................................................... 7  5.2 Site Preparation .................................................................................................................. 7  5.3 Utility Trenching .................................................................................................................. 9  5.4 Pavement Sections .......................................................................................................... 12  6.0 GENERAL COMMENTS ...................................................................................................... 14  FIGURES Figure 1 — Site Location Map Figure 2 — Site & Exploration Plan Figure 3 — Site & Exploration Profile APPENDIX A – Field Exploration Procedures, General Notes, and Logs APPENDIX B – Laboratory Testing Procedures, Soil Classifications and Results APPENDIX C – Supplemental Information Geotechnical Engineering Report D Street NE Utility Improvements ■ Auburn, WA June 4, 2013 ■ Terracon Project No. 81135017 EXECUTIVE SUMMARY Terracon has completed a geotechnical subgrade evaluation for the proposed installation of new underground utilities along the project alignment. Our scope of work included ten exploratory borings, limited laboratory soil testing, geotechnical analysis, and preparation of this report. Based on our findings, we have derived the following geotechnical conclusions and recommendations:  Existing Pavements: Our borings revealed that the existing pavement section generally comprises about 6½ inches of cement concrete over about 1 to 1½ feet of medium dense gravelly sands (interpreted as subbase fill).  Soil Conditions: The site appears to be underlain by very loose to medium dense silty sands, and very soft to medium stiff silts and clays. At depths greater than about 10 feet, we observed loose to medium dense sands and soft, sandy silts or clayey silts. We infer that interlayered alluvial sands and silts of these types continue downward to depths greater than 100 feet throughout the site vicinity.  Groundwater Conditions: Our borings disclosed groundwater at depths of about 4½ to 5 feet below ground surface at the time of drilling.  Geological Hazards: Although not shown on King County’s regional hazard maps, subsurface liquefaction presents a widespread risk throughout the site, in our opinion. However, we do not infer that this will impose any constraints on the proposed improvements.  Trenching Considerations: Shallow trenches can likely be excavated with temporary sideslopes laid back at appropriate inclinations. Deeper trenches will likely require temporary shoring systems such as trench boxes, strut-supported panels, or driven sheet piles. Dewatering systems such as internal sumps and pumps or external extraction wellpoints will likely be needed in all deep trenches.  Earthwork Considerations: The on-site soils have a moderate to high fines content, which renders them generally unsuitable for reuse as on-site fill material. However, the existing cement concrete pavement (if properly crushed) and granular subbase material appear suitable for reuse. This summary should be used only in conjunction with the entire report for design purposes. It should be recognized that geotechnical details were not included or not fully developed in this section; as such, the report must be read in its entirety for a comprehensive understanding of the items presented above. Also, please refer to the GENERAL COMMENTS section for a discussion of the report limitations. Page 1 of 19 Terracon Consultants, Inc. 21905 – 64th A venue, Suite 100 Mountlake Terrace, Washington 98043 P [425] 771-3304 F [425] 771-3549 terracon.com GEOTECHNICAL SUBGRADE REPORT D STREET NE UTILITY IMPROVEMENTS S. 277TH STREET TO AUBURN WAY N. AUBURN, WASHINGTON Terracon Project No. 81135017 June 4, 2013 1.0 INTRODUCTION This report presents the results of our geotechnical subgrade evaluation performed for the proposed utility improvements at the subject site. The purpose of our evaluation was to provide geotechnical characterizations, conclusions, and recommendations concerning the following elements of the project:  Existing pavement removal  Utility trenching  Temporary dewatering  Trench backfilling  Temporary shoring  New asphaltic pavements 2.0 PROJECT INFORMATION The following sections present information regarding site delineation, existing site usage, proposed development features, and our geotechnical scope of work. Terracon should be notified if any significant changes are made in the proposed site location, layout, or details. 2.1 Site Delineation The project alignment comprises an existing segment of D Street NE located in northwestern Auburn, Washington. Specifically, the alignment extends from S. 277th Street to Auburn Way N., a distance of approximately 1500 linear feet. One other roadway, 49th Street NE, crosses the project segment near its midpoint. Table 1, below, summarizes our understanding of the site location and boundaries, as gained from maps, survey plans, aerial photos, team communications, and a site reconnaissance. Figure 1 shows the general site location in relation to surrounding roadways. Figure 2 illustrates the various land parcels adjoining the subject roadway. Geotechnical Subgrade Evaluation D Street NE Utility Improvements ■ Auburn, WA June 4, 2013 ■ Terracon Project No. 81135017 Reliable ■ Responsive ■ Convenient ■ Innovative 2 TABLE 1 SUMMARY OF PROJECT SITE DELINEATION Parameter General Description Township / Range / Section NW ¼ & SW ¼, Sect. 31, T22N, R5E Latitude / Longitude Lat = 47.35 deg. Lon = -122.23 deg. Geometry Overall Alignment: Straight, with curve at south end. Approximate Length: 1500 feet. Approximate Width: 30 feet. Visual Boundaries North End: S. 277th Street (arterial roadway). South End: Auburn Way N. (arterial roadway). West Side: Commercial and some residential properties. East Side: Commercial properties (developed and undeveloped). 2.2 Existing Site Usage This project segment presently consists of a low- to moderate-traffic-volume, low- to moderate- speed, two-lane roadway that provides access to the adjacent commercial and residential properties. Due to its location between S. 277th Street and Auburn Way N., the subject roadway is also used as a connector route between these two arterials. 2.3 Proposed Site Development Current improvement plans for the subject segment of D Street NE call for a combination of underground utility and pavement upgrades. These include the following items:  Removing the existing cement concrete pavement over the western half of the roadway width between S. 277th Street and 49th Street NE.  Removing the existing cement concrete pavement over the entire roadway width between 49th Street NE and Auburn Way N.  Installing new underground utilities below the roadway segment. We understand that the new utilities will include sewer, water, and storm, with a maximum depth of about 14 feet below existing grades.  Installing temporary shoring for the deep sewer trench where needed. We anticipate that most or all shoring needs will be handled using conventional trench boxes or strut- supported panels, but sheet piles might be installed if warranted by high groundwater.  Resurfacing the roadway with asphalt concrete pavement. The new pavement will have a width of approximately 22 feet, which matches the existing pavement width, except for a new flared portion near the intersection with Auburn Way N. Geotechnical Subgrade Evaluation D Street NE Utility Improvements ■ Auburn, WA June 4, 2013 ■ Terracon Project No. 81135017 Reliable ■ Responsive ■ Convenient ■ Innovative 3 2.4 Scope of Work We performed all geotechnical services in general accordance with our previously mentioned proposal. It should be noted that our authorized scope of services did not include any environmental characterization or testing of on-site soil samples. We ultimately completed the following geotechnical scope items:  Reviewed topographic maps, aerial photographs, surface photographs, municipal hazard maps, and geologic maps regarding the site vicinity.  Performed a surface reconnaissance of the site and immediate vicinity.  Advanced ten exploratory borings (designated B-1 through B-10) to depths ranging up to about 25 feet below existing grades, at a roughly uniform spacing along the alignment.  Performed limited geotechnical laboratory testing on representative samples of the near- surface soils.  Analyzed subsurface conditions in relation to the proposed improvements, and prepared this written report. The functional locations, elevations, and depths associated with our recent on-site explorations are summarized in Table 2, and their relative locations are illustrated on Figure 2. Appendix A describes our field exploration procedures, and Appendix B describes our laboratory testing procedures. TABLE 2 SUMMARY OF SITE EXPLORATION PROGRAM Exploration Functional Location Surface Elevation (feet) Termination Depth (feet) B-1 B-2 B-3 B-4 B-5 B-6 B-7 B-8 B-9 B-10 Southern end of roadway segment Southern portion of roadway segment Southern portion of roadway segment Southern portion of roadway segment Middle portion of roadway segment Middle portion of roadway segment Northern portion of roadway segment Northern portion of roadway segment Northern portion of roadway segment Northern end of roadway segment 50 50 50 50 50 50 50 50 50 51½ 26½ 16½ 11½ 16½ 26½ 16½ 16½ 11½ 16½ 26½ Note: All exploration depths and elevations should be regarded as only approximate values. Elevation datum: 2013 King County iMap. Geotechnical Subgrade Evaluation D Street NE Utility Improvements ■ Auburn, WA June 4, 2013 ■ Terracon Project No. 81135017 Reliable ■ Responsive ■ Convenient ■ Innovative 4 3.0 SITE SETTING We obtained information concerning regional conditions in the site vicinity from a review of topographic maps published by the U.S. Geological Survey (USGS), geologic maps published by GeoMap Northwest, and on-line zoning maps prepared by King County. Our research findings are discussed below, and excerpts from selected maps and photo files are contained in Appendix C. 3.1 Regional Geography Topographically, the project site is situated within a broad alluvial plain formed by the Green River. This plain has an east–west width of about 3 miles and a north–south length of many miles. Regional surface grades throughout the alluvial plain are relatively flat, with a surface elevation on the order of 50 feet (USGS datum). Judging by the general topography, it appears that very little cutting and filling has been performed as part of the overall neighborhood development. Meanders of the Green River lie approximately 1 mile east and 1 mile north of the site. 3.2 Regional Geology According to the 2007 Geologic Map of King County, the entire Green River alluvial plain is underlain by Quaternary-age alluvial deposits. These deposits typically comprise layers of loose to medium dense sands, silty sands, and gravelly sands, and soft to stiff silts, sandy silts, and clayey silts. Throughout the Auburn area, the total thickness of alluvial sediments typically exceeds 100 feet. The upland areas east and west of the alluvial plain are mapped as glacial till, which tends to form a cap over ridges and other high features. 3.3 Regional Zoning King County’s regional zoning maps show approximate locations where geological hazards and other environmentally sensitive areas are documented or suspected. According to these maps, there are no potential or known landslide areas, erosion zones, or coal mines within or near the site vicinity. Interestingly, the maps show a seismic liquefaction hazard zone closely west and north of the site, but not encompassing the site. Because this liquefaction zone is delineated by roadways and property lines, rather than by natural geographic features, we interpret the mapped boundaries to be largely artificial. Geotechnical Subgrade Evaluation D Street NE Utility Improvements ■ Auburn, WA June 4, 2013 ■ Terracon Project No. 81135017 Reliable ■ Responsive ■ Convenient ■ Innovative 5 4.0 SITE CONDITIONS Terracon representatives visited the project site several times during March and April of 2013 to evaluate surface and subsurface conditions. Our geotechnical observations, measurements, findings, and interpretations are described in the following text sections. 4.1 Surface Features The following paragraphs briefly discuss existing surface features along the subject roadway, as observed or inferred during our site reconnaissance and exploration.  Surface Grades: Most of the subject roadway is fairly flat and level, with grades that closely match the adjacent land areas. The general surface elevation is about 50 feet (USGS datum). However, the northern end of the roadway slopes upwards approximately 4 feet to match the higher grades of S. 277th Street. It appears that a wedge of fill soil was placed here to accommodate this grade change.  Existing Pavement: The subject roadway is paved with cement concrete, which was placed in 30-foot-long panels. This pavement generally appears to be in fair to poor condition; we observed numerous lateral and longitudinal cracks in the pavement, as well as moderate faulting at many of the panel joints. Our exploratory borings revealed that this pavement ranges from about 6 to 8 inches thick, with a typical thickness of 6½ inches. We did not observe a crushed aggregate base course below the pavement. At the northern end of the roadway, where it transitions to the higher grade of S. 277th Street, the old cement concrete pavement is covered by 4 inches of asphalt concrete pavement and 12 inches of granular fill soils.  Roadside Improvements: There are no curbs, gutters, sidewalks, or other improvements on either side of the subject roadway. Drainage ditches and paved shoulders are present only in a few locations. Generally, roadway surface water simply sheets off to the adjacent properties. At the time of our site reconnaissance, which occurred after a rainstorm, we observed numerous medium to large puddles of standing water on or beside the roadway.  Underground Utilities: Based on utility locating personnel, a 6-inch-diameter natural gas line underlies the eastern side of the entire roadway segment, and a 2-inch-diameter natural gas line underlies the western side of the roadway segment north of 49th Street NE. In addition, utility markings indicated that a sewer line underlies the western shoulder of the roadway and that a storm drain crosses the roadway at several locations. Markings for a buried water line were observed on the eastern side of the roadway. Power lines are located overhead, but there appear to be underground crossings at one or more locations. Geotechnical Subgrade Evaluation D Street NE Utility Improvements ■ Auburn, WA June 4, 2013 ■ Terracon Project No. 81135017 Reliable ■ Responsive ■ Convenient ■ Innovative 6 4.2 Soil Stratigraphy Our exploratory borings revealed that the subject roadway is underlain by soil conditions that are somewhat variable laterally and vertically but typical of alluvial deposits in this region. The following paragraphs describe our soil observations, and Figure 3 illustrates our stratigraphic interpretations. The boring logs contained in Appendix A and the lab sheets contained in Appendix B provide details regarding on-site soil conditions. Although our scope of work did not involve any sampling or testing for possible environmental soil contaminants, it should be noted that we did not detect any petroleum sheens or odors in any of the soil samples that we obtained.  Surficial Fill Soils: All of our exploratory borings except B-10 (located at the northern end of the alignment) disclosed a layer of gravelly sands with some silt immediately beneath the cement concrete pavement. This layer was only about 1 to 1½ feet thick, and it was generally medium dense. We interpret this surficial soil layer to represent a subbase course of imported fill below the pavement (there does not appear to be a crushed aggregate base course). In boring B-10, however, the CCP was underlain by a 2-foot-thick base course of medium dense gravel with silt and sand.  Upper Native Soils: Immediately beneath the surficial fill soils, we observed native alluvial soils consisting of silty sands, sandy silts, clayey silts, and silty clays. These upper native soils generally ranged from very loose to medium dense or very soft to medium stiff. Our laboratory testing performed on representative samples revealed a fines (silt and clay) content ranging from about 6 to 75 percent, a sand content ranging from about 44 to 92 percent, and a field moisture content ranging from about 23 to 30 percent. Our two Atterberg limits tests performed on the native silts disclosed low- plasticity or non-plastic conditions.  Deeper Native Soils: At depths greater than about 10 feet or so, our deeper borings generally revealed loose to medium dense sands with a trace of silt below the southern portion of the roadway, and soft, sandy silts or clayey silts below the northern portion. These native alluvial soils extended beyond the termination depths of all borings. We infer that interlayered alluvial sands and silts of these types continue downward to depths greater than 100 feet throughout the site vicinity. 4.3 Groundwater Levels Our exploratory borings disclosed consistent groundwater conditions below the subject roadway. Groundwater depths at the time of drilling were typically 4½ to 5 feet, which corresponds to a groundwater elevation of about 45 feet (USGS datum). We infer that these depths and elevations are fairly uniform throughout the site vicinity. It should be noted, however, that groundwater conditions probably fluctuate with season, precipitation patterns, on- site or off-site usage, and other factors. Geotechnical Subgrade Evaluation D Street NE Utility Improvements ■ Auburn, WA June 4, 2013 ■ Terracon Project No. 81135017 Reliable ■ Responsive ■ Convenient ■ Innovative 7 5.0 CONCLUSIONS AND RECOMMENDATIONS Based on our surface reconnaissance, subsurface exploration, and document research, we conclude that the proposed roadway improvements are feasible from a geotechnical standpoint, contingent on proper design implementation and construction practices. Our geotechnical conclusions and recommendations concerning general design considerations, site preparation, utility trenching, pavement sections, and structural fill are presented in the following text sections. ASTM specification codes cited herein refer to the 2010 manual published by the American Society for Testing & Materials. WSDOT codes refer to the 2012 edition of Standard Specifications for Road, Bridge, and Municipal Construction published by Washington State Department of Transportation. 5.1 General Design Considerations We offer the following comments, conclusions, and recommendations concerning general geotechnical design issues affecting the overall development. Geological Hazards: Although King County’s on-line regional maps do not show any geological hazard areas within the site, we infer that earthquake-induced liquefaction represents a persistent risk at the site and throughout the entire site vicinity. However, because no buildings or other above-grade structures are planned for the project, we feel that this liquefaction risk does not present a significant project constraint. Earthwork Considerations: Our exploratory borings disclosed generally silty soils and shallow groundwater underlying the site. These soil and groundwater conditions will complicate general earthwork operations associated with site preparation, utility trench excavation, trench backfilling, and paving. As such, we recommend that earthwork be scheduled for the drier summer and fall months if possible. Regardless of earthwork schedule, dewatering will likely be needed to facilitate installation of the new sewerline and any other utilities located more than about 5 feet below ground surface. 5.2 Site Preparation Preparation of the project site will involve tasks such as demolition, temporary drainage, pavement removal, and erosion control. The paragraphs below present our geotechnical comments and recommendations concerning these various issues. Temporary Drainage: Before stripping or trenching activities begin, any sources of surface or near-surface water that could potentially enter the construction zone should be intercepted and diverted. We tentatively anticipate that a system of temporary curbs, berms, or swales placed around upslope areas will adequately intercept most surface water runoff. However, the Geotechnical Subgrade Evaluation D Street NE Utility Improvements ■ Auburn, WA June 4, 2013 ■ Terracon Project No. 81135017 Reliable ■ Responsive ■ Convenient ■ Innovative 8 selection of an appropriate drainage system will depend on the water quantity, season, weather conditions, construction sequence, and contractor's methods; therefore, final decisions regarding temporary drainage details are best made in the field at the time of construction. Existing Pavement Thickness: After surface and near-surface water sources have been controlled, the existing pavements should be stripped from all planned construction areas. Our exploratory borings revealed that the existing cement concrete pavement (CCP) has a typical thickness of about 6½ inches over most of the subject roadway but with thicknesses ranging up to almost 8 inches in certain locations. At the northern end of the roadway (near S. 277th Street), the CCP is overlain by 4 inches of asphalt concrete pavement (ACP) and about 1 foot of granular fill. The contractor should realize that pavement types and thicknesses could potentially vary significantly over the entire roadway width and length. Pavement Removal Methods: The existing CCP could be removed either in a conventional manner or by rubblizing it in place. Both methods are discussed below.  Conventional Removal: This would involve breaking the CCP into pieces on the order of 2 to 4 feet wide by means of an impact breaker or similar device. The individual pieces could then be picked up and loaded into a dumptruck for export. Advantages of this method include the following: can be performed using conventional earthworking equipment; generates less noise and dust; reduces time requirements. It should also be mentioned that the exported pieces could be crushed at an off-site location and then transported back to the site for use as recycled fill.  In-Place Rubblization: This would involve breaking the CCP into small particles on the order of 1 to 2 inches wide by means of a vibratory rubblizing machine. The resulting particles could then be scooped up and loaded into a dumptruck for export or, alternatively, left on site for future reuse. Advantages of this method include the following: reduces volume of waste material being exported; can reduce import material quantities by providing a source for structural aggregate; provides an opportunity for the City to demonstrate good recycling practices. Subbase Stripping: After removal of the existing pavement, either by conventional means or rubblizing, it may be advantageous to strip and stockpile the existing subbase course located within new utility trenching areas. This would allow the subbase material to be reused later as on-site structural fill, contingent on a suitable moisture content at the time of placement. Our exploratory borings revealed that the subbase course comprises approximately 1 to 1½ feet of gravelly sand with some silt. Although not highly moisture-sensitive compared to other site soils, this material might be difficult to reuse during very wet site conditions. Geotechnical Subgrade Evaluation D Street NE Utility Improvements ■ Auburn, WA June 4, 2013 ■ Terracon Project No. 81135017 Reliable ■ Responsive ■ Convenient ■ Innovative 9 5.3 Utility Trenching We anticipate that the new waterline and most of the new drainlines to be installed along D Street will be relatively shallow, with maximum depths of about 3 to 5 feet. In contrast, we understand that the new sewerline will have a depth ranging up to about 14 feet below existing ground surface. The following paragraphs present our geotechnical conclusions and recommendations concerning both shallow and deep utility trenches. Our attached Site & Exploration Profile (Figure 3) can be used as an aid in planning for subsurface conditions. Shallow Trench Conditions: Based on our exploratory borings, the trench excavations for relatively shallow utilities (those having a maximum depth of about 5 feet) will encounter primarily loose to medium dense, silty sands. Our borings also indicate that these shallow trenches will be mostly or entirely above the local groundwater level, which we observed at depths of about 4½ to 5 feet in most borings at the time of exploration. Deep Trench Conditions: Based on our exploratory borings, the trench excavations for relatively deep utilities (those having a maximum depth in the range of 5 to 15 feet) will encounter somewhat differing soil conditions, depending on location. Trenches in the northern portion of roadway (between S. 277th Street and 49th Street NE) will likely encounter loose to medium dense, silty sands transitioning into soft, sandy silts, clayey silts, or silty clays. Trenches in the southern portion of roadway (between 49th Street NE and Auburn Way N.) will likely encounter loose to medium dense, silty sands transitioning into loose sands with a trace of silt. Our borings also indicate that these deep trenches will extend well below the local groundwater level. Temporary Cut Slopes: We anticipate that shallow utility trenches can be excavated using temporary cut slopes, provided that there is adequate lateral lay-back space on each side of the trench. Typical inclinations for temporary cut slopes in alluvial soils range from 2H:1V to 1H:1V (horizontal:vertical), depending on the soil type, groundwater level, prevailing weather, duration of exposure, and other factors. For all on-site trenches, the earthwork contractor should be made responsible for determining an appropriate slope inclination on the basis of specific conditions encountered. Even after excavating a trench, the contractor should continue to monitor the temporary slopes and make appropriate adjustments in response to changing conditions. In all cases, the slope inclinations should comply with current OSHA and/or WISHA safety requirements. Temporary Shoring Options: We anticipate that deep utility trenches will require temporary shoring in order to limit lateral excavation requirements and to help control groundwater seepage. In our opinion, suitable shoring options could include prefabricated trench boxes, strut-supported panels, or driven sheet piling, depending on the trench depth, the contractor’s approach to groundwater control, and other factors. All three options are discussed below. Geotechnical Subgrade Evaluation D Street NE Utility Improvements ■ Auburn, WA June 4, 2013 ■ Terracon Project No. 81135017 Reliable ■ Responsive ■ Convenient ■ Innovative 10  Trench Box and Panel Systems: These two systems are generally less expensive and faster to install than sheet piles. However, the overall rigidity of either system requires the use of higher “at-rest” earth pressures. Also, because the boxes or panels typically do not extend below the trench bottom, they impose a greater demand on the trench dewatering system. The following geotechnical criteria would be appropriate for the contractor’s use in selecting a temporary shoring system composed of trench boxes or strut-supported panels. Shoring Design Parameter Recommended Value At-Rest Earth Pressure (upper 4 feet) At-Rest Earth Pressure (below 4 feet) 55 pcf 90 pcf  Sheet Pile Systems: A sheet pile shoring wall is generally more expensive and time- consuming to install than the aforementioned systems. However, because they are inherently more flexible, they can be designed for lower “active” earth pressures. In addition, because sheet piles must extend a significant distance below the trench bottom, they reduce the demand on the trench dewatering system. The following geotechnical criteria would be appropriate for the contractor’s use in designing a temporary shoring system composed of driven sheet piles, where “H” represents the exposed height of the sheet piles above the trench bottom. Shoring Design Parameter Recommended Value Active Earth Pressure (upper 4 feet) Active Earth Pressure (below 4 feet) Passive Earth Pressure (allowable) Sheet Pile Embedment (minimum) 35 pcf 80 pcf 200 pcf 2(H) feet Temporary Dewatering: Due to the presence of groundwater at depths on the order of 4 to 5 feet, we anticipate that deep utility trenches will require some form of temporary dewatering. Possible dewatering systems could consist of internal sumps and pumps or external extraction wellpoints, depending on the trench depth, shoring system type, and prevailing conditions. In general, external extraction wellpoints could be used with any of the shoring systems or trench depths, whereas internal sumps and pumps would be practical only in shallow trenches or if used in conjunction with sheet piles and a “mud seal” along the trench bottom. We recommend that the contractor be made responsible for designing and installing an effective dewatering system that provides for reasonably dry trench conditions without adversely affecting surrounding structures or other features. Geotechnical Subgrade Evaluation D Street NE Utility Improvements ■ Auburn, WA June 4, 2013 ■ Terracon Project No. 81135017 Reliable ■ Responsive ■ Convenient ■ Innovative 11 Trench Bottoms: The bottom of all trenches should be excavated neatly into firm soils so as to create a bearing subgrade for the new utilities. If any mud, peat, soft silt, soft clay, or other unsuitable bearing material is exposed on the trench bottom, we recommend that these subgrade soils be vertically overexcavated by at least 1 foot and replaced with a coarse aggregate such as locally available 2- to 4-inch quarry spalls or 8-inch-minus quarry spalls per WSDOT: 9-13.6. The coarse aggregate should be bucket-tamped into place and then covered with a durable separation geotextile such as Mirafi 500X. Pipe Bedding: We recommend that at least 6 inches of bedding material be placed around all utility pipes to provide protection during subsequent trench backfilling. All pipe bedding should conform to the requirements for “Gravel Backfill for Pipe Zone Bedding” per WSDOT: 9- 03.12(3), unless other specific criteria are provided by the pipe manufacturer/supplier. After placement, the bedding should be hand-rodded or hand-tamped under the pipe haunches; mechanical compaction should be avoided due to the risk of pipe damage. Conventional Trench Backfill: From the pipe bedding upward, utility trench backfill should generally consist of granular fill meeting the requirements of “Gravel Borrow” per WSDOT: 9- 03.14(1). It would be acceptable to use crushed recycled concrete for this purpose if it has been processed to meet the same requirements. If the existing roadway subbase course has been stripped and stockpiled, as previously recommended, it could also be used as trench backfill. None of the underlying native alluvial site soils appear to be reusable as trench backfill material. Lightweight Trench Backfill: Due to the depth and settlement-sensitivity of the proposed sewerline, we anticipate that conventional trench backfill could create excessive long-term settlements of this pipe. Consequently, we recommend that lightweight backfill be used in place of the lowest 2 feet of conventional backfill. This lightweight backfill could consist of either wood chips (also known as “hog fuel”) or pumice gravel. Due to the potential for long-term decomposition, wood chips should be used only in trenches that are sufficiently deep such that the wood chips will stay below the lowest groundwater level. An annual low groundwater depth of 10 feet below ground surface can be assumed for planning purposes. Conventional Backfill Placement and Compaction: All conventional trench backfill should be placed in horizontal layers, or “lifts,” typically not exceeding 8 inches in loose thickness. However, the initial lift thickness could be increased to levels recommended by the manufacturer in order to protect utilities from damage by compacting equipment. Each backfill lift should be compacted by means of a vibratory roller, arm-mounted vibratory plate (“hoe- packer”), impact tamper (“jumping jack”), or other suitable mechanical device. Water-jetting and flooding are not acceptable methods of compaction, in our opinion. Regardless of method, the backfill should be compacted according to the following standards (based on ASTM: D-1557). Geotechnical Subgrade Evaluation D Street NE Utility Improvements ■ Auburn, WA June 4, 2013 ■ Terracon Project No. 81135017 Reliable ■ Responsive ■ Convenient ■ Innovative 12 Trench Backfill Location Minimum Compaction Upper 2 feet Below 2 feet 95 percent 90 percent Lightweight Backfill Placement and Compaction: All lightweight backfill used in the deep sewerline trench should be placed in horizontal layers, or “lifts,” not exceeding 12 inches in loose thickness. To achieve a reasonable backfill density without over-stressing the sewerline, we recommend compacting each lift by making at least two complete passes with a low-stress device, such as a small walk-behind vibratory roller or a large vibratory plate. The use of a high- stress compactor, such as an arm-mounted vibratory plate (“hoe-packer”) or large vibratory roller, should be avoided. Water-jetting and flooding are not acceptable methods of compaction, in our opinion. Utility Pipe Gradients: Due to the presence of compressible and liquefiable soils extending considerable depths below the site, there is some risk of long-term utility settlements even if all of our previously recommended mitigation measures are implemented. For this reason, it would be advantageous to provide a greater-than-normal gradient in the sewerline, drainlines, and any other gravity-flow pipes. 5.4 Pavement Sections We understand that asphalt concrete pavement (ACP) will be used to replace the existing cement concrete pavement (CCP) wherever the CCP is removed during earthwork. The following comments and recommendations are given for ACP design and construction purposes. Soil Design Values: The near-surface native soils underlying the existing CCP and subbase course generally consist of loose to medium dense, silty sands. Our scope of work did not include a California Bearing Ratio (CBR) or other specific bearing test on this material. However, based on our textural correlations and local experience, we infer that these native soils will provide a CBR value in the range of 3 to 6 when compacted to 95 percent of the soil’s maximum dry density. Correlation charts indicate that this CBR range corresponds to a Resilient Modulus on the order of 4000 psi. Traffic Design Values: Pavement designs are typically based on an Equivalent 18-kip Single- Axle Load (ESAL), a Traffic Index (TI), or other traffic loading value. Because no specific traffic data has been provided for this project, we have assumed an ESAL of 200,000 for design purposes. This value corresponds to frequent use by passenger vehicles and occasional use by heavy trucks. If the City later determines that a different traffic loading condition would be appropriate, we would need to recalculate the pavement section. Geotechnical Subgrade Evaluation D Street NE Utility Improvements ■ Auburn, WA June 4, 2013 ■ Terracon Project No. 81135017 Reliable ■ Responsive ■ Convenient ■ Innovative 13 Recommended Pavement Section: We applied the aforementioned soil and traffic design values to a conventional AASHTO design procedure in order to derive an appropriate pavement section for the subject roadway. Our recommended minimum pavement section is presented below, and Appendix C contains our analysis sheets. Pavement Section Layer Minimum Value Asphalt Concrete Pavement (ACP) Crushed Aggregate Base (CAB) Granular Subbase (GSB) 4 inches 4 inches 10 inches Pavement Layer Details: Our geotechnical recommendations concerning the individual pavement layers are provided in the following paragraphs.  Asphalt Concrete Pavement: We recommend that the ACP aggregate gradation conform to the control points for a ½-inch mix (per WSDOT: 9-03.8(6)) and that the binder conform to PG 58-22 criteria (per WSDOT: 9-02.1(4)). We also recommend that the ACP be compacted to a target average density of 92 percent, with no individual locations compacted to less than 90 percent nor more than 96 percent, based on the Rice theoretical maximum density for that material (per ASTM: D-2041). According to standard paving practice, the ACP course should be placed in two separate lifts of equal thickness.  Crushed Aggregate Base: We recommend that all CAB material conform to the criteria for “Crushed Surfacing Base Course” per WSDOT: 9-03.9(3). It would also be acceptable to use up to 20 percent of crushed recycled CCP within the CAB, provided that the overall mixture meets the same textural criteria. Regardless of mixture, all CAB material should be compacted to a minimum density of 95 percent based on the Modified Proctor maximum dry density (per ASTM: D-1557).  Granular Subbase: We recommend all GSB material conform to the criteria for “Ballast” per WSDOT: 9-03.9(1). It would also be acceptable to use up to 100 percent crushed recycled CCP or up to 20 percent of crushed recycled ACP within the GSB, provided that the overall mixture meets the same textural criteria. Regardless of mixture, all GSB material should be compacted to a minimum density of 95 percent based on the Modified Proctor maximum dry density (per ASTM: D-1557). Subgrade Preparation: All pavement subgrades should be compacted to a firm and unyielding condition before any pavement layers are placed. We recommend using a vibratory roller in granular (sand or gravel) subgrade areas and a static roller in cohesive (silt or clay) subgrade areas. The resulting subgrade condition should then be verified by proof-rolling with a loaded Geotechnical Subgrade Evaluation D Street NE Utility Improvements ■ Auburn, WA June 4, 2013 ■ Terracon Project No. 81135017 Reliable ■ Responsive ■ Convenient ■ Innovative 14 dump truck or other heavy construction vehicle, in the presence of a geotechnical representative. Compaction Testing: Compaction of the CAB and GSB layers should be verified qualitatively by method observations, proof-rolling, and hand-probing, as well as quantitatively by nuclear densometer testing. Compaction of the ACP layer should be measured by nuclear densometer testing at the time of placement and subsequently verified by laboratory testing of representative core samples. Pavement Life and Maintenance: It should be realized that asphaltic pavements are not maintenance-free. The above-described pavement section represents our recommended minimum thicknesses for an average level of performance during a 20-year design life. During this time period, an average level of maintenance will likely be required. Furthermore, a 20-year pavement life typically assumes that an overlay will be placed after about 10 years. A thicker section would offer better long-term performance but would cost more initially, whereas a thinner section would be more susceptible to "alligator" cracking and other failure modes. As such, pavement design can be considered a compromise between a high initial cost and low maintenance costs versus a low initial cost and higher maintenance costs. 6.0 GENERAL COMMENTS Terracon should be retained to review the final design plans and specifications so comments can be made regarding interpretation and implementation of our geotechnical recommendations in the design and specifications. Terracon also should be retained to provide observation and testing services during grading, excavation, foundation construction, and other earth-related construction phases of the project. The analysis and recommendations presented in this report are based upon the data obtained from the explorations performed at the indicated locations and from other information discussed in this report. This report does not reflect variations that may occur between explorations, across the site, or due to the modifying effects of construction or weather. The nature and extent of such variations may not become evident until during or after construction. If variations appear, we should be immediately notified so that further evaluation and supplemental recommendations can be provided. The scope of services for this geotechnical project does not include either specifically or by implication any environmental or biological (such as mold, fungi, and bacteria) assessment of the site, nor any identification or prevention of pollutants, hazardous materials or conditions. Our companion Phase 1 environmental report should be consulted regarding such information. Geotechnical Subgrade Evaluation D Street NE Utility Improvements ■ Auburn, WA June 4, 2013 ■ Terracon Project No. 81135017 Reliable ■ Responsive ■ Convenient ■ Innovative 15 This report has been prepared for the exclusive use of our client, for specific application to the currently proposed project, and in accordance with generally accepted geotechnical engineering practices. No warranties, either express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Terracon reviews the changes and either verifies or modifies the conclusions of this report in writing. 81135017 FIGURES FIGURE 1 — SITE LOCATION MAP FIGURE 2 — SITE & EXPLORATION PLAN FIGURE 3 — SITE & EXPLORATION PROFILE N Project Mngr: Approved By: Checked By: Drawn By: Project No. Scale: Date: File No. FIG. No. Consulting Engineers and Scientists 21905 64th Avenue W., Ste 100Mountlake Terrace, WA 98043 FAX. (425) 771-3549PH. (425) 771-3304 SITE LOCATION MAP City of Auburn Auburn, Washington D Street Utility Improvements April 2013 Figure 1.dwg Not to Scale 81135017 JMB RWS SGP JMB 1 Basemap PDF file provided by the City of Auburn and modified by TERRACON. N BORING NUMBER AND APPROXIMATE LOCATION B-1 LEGEND: Project Mngr: Approved By: Checked By: Drawn By: Project No. Scale: Date: File No. Fig. No. Consulting Engineers and Scientists 21905 64th Avenue W., Ste 100Mountlake Terrace, WA 98043 FAX. (425) 771-3549PH. (425) 771-3304 SITE AND EXPLORATION PLAN City of Auburn Auburn, Washington D Street Utility Improvements April 2013 Exhibit A-2*.dwg AS SHOWN 81135017 JMB RWS RWS JMB 2 Basemap PDF file provided by City of Auburn and modified by TERRACON. B-10 B-9 B-8 B-7 B-6 B-5 B-4 B-3 B-2 B-1 SCALE IN FEET 0200 50 200100 81135017 APPENDIX A FIELD EXPLORATION PROCEDURES, NOTES, AND LOGS 81135017 FIELD EXPLORATION PROCEDURES The following paragraphs describe our procedures associated with the on-site subsurface explorations and field tests that we conducted for this project. Interpretive stratigraphic logs of our auger borings are enclosed in this appendix. Our scope of work did not include a precise survey of each exploration location. Instead, all horizontal positions were determined by pacing or taping distances from existing site features, and all depths were referenced to existing site grade. As such, the locations and depths given in the report text, shown on the report figures, and stated on the stratigraphic logs should be considered accurate only to the degree implied by our measuring methods. Auger Borings All borings were advanced with a hollow-stem auger, using a trailer-mounted drill rig operated by an independent drilling firm (Boretec-1, Inc.) working under subcontract to Terracon. Before drilling, access holes were cut through the existing pavement using a coring drill. As each boring was completed, the borehole was backfilled with suitable materials and the surface was patched with asphalt or concrete. Excess soil cuttings were left on site in discreet locations. A geotechnical specialist from our firm continuously observed the borings, logged the subsurface conditions, and collected representative soil samples. Throughout the drilling operation, soil samples were obtained at 2½- or 5-foot depth intervals by means of the Standard Penetration Test (SPT) per ASTM: D-1586. All samples were stored in watertight containers and later transported to our laboratory for further visual examination. Interpretive stratigraphic logs of our explorations are enclosed in this appendix. 81135017 0.7 2.0 3.5 13.0 7.75" CONCRETE FILL - GRAVELLY SAND (SP), with silt, brown, medium dense, moist SILTY SAND (SP-SM), brown, loose to medium dense, moist SILTY SAND (SM), brown, medium dense, moist grayish-brown, medium stiff, becomes wet very loose, wet sandy silt interbeds observed gray, very loose, silty fine sand POORLY GRADED SAND (SP), trace silt, black, loose, wet S-1 S-2 S-3 S-4 S-5 12 12 12 12 14 49.5+/- 48+/- 46.5+/- 37+/- 5-6-4 N=10 1-2-1 N=3 2-0-1 N=1 1-1-2 N=3 2-4-5 N=9 See Exhibit A-2 Hammer Type: Rope & CatheadStratification lines are approximate. In-situ, the transition may be gradual. LOCATION DEPTH GR A P H I C L O G TH I S B O R I N G L O G I S N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . D Street NE Auburn, Washington SITE: 4.5' While Drilling WATER LEVEL OBSERVATIONS PROJECT: D Street NE Improvements Page 1 of 2 Advancement Method: Hollow Stem Auger Abandonment Method: Borings backfilled with bentonite chips upon completion 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington Notes: Project No.: 81135017 Drill Rig: EC85 Boring Started: 4/4/2013 BORING LOG NO. B-1 City of Auburn Department of Public WorksCLIENT: Auburn, WA Driller: Boretec Boring Completed: 4/4/2013 Exhibit: Elevations taken from King County iMAP A-4 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. SA M P L E N U M B E R RE C O V E R Y ( I n . ) ELEVATION (Ft.)PE R C E N T F I N E S WA T E R CO N T E N T ( % ) FI E L D T E S T RE S U L T S WA T E R L E V E L OB S E R V A T I O N S Approximate Surface Elev: 50 (Ft.) +/- SA M P L E T Y P E DE P T H ( F t . ) 5 10 15 20 26.5 POORLY GRADED SAND (SP), trace silt, black, loose, wet (continued) medium dense, 6 inches of heave tapped through sandy silt laminations observed Boring Terminated at 26.5 Feet S-6 S-7 14 14 23.5+/- 4-6-9 N=15 5-9-9 N=18 See Exhibit A-2 Hammer Type: Rope & CatheadStratification lines are approximate. In-situ, the transition may be gradual. LOCATION DEPTH GR A P H I C L O G TH I S B O R I N G L O G I S N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . D Street NE Auburn, Washington SITE: 4.5' While Drilling WATER LEVEL OBSERVATIONS PROJECT: D Street NE Improvements Page 2 of 2 Advancement Method: Hollow Stem Auger Abandonment Method: Borings backfilled with bentonite chips upon completion 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington Notes: Project No.: 81135017 Drill Rig: EC85 Boring Started: 4/4/2013 BORING LOG NO. B-1 City of Auburn Department of Public WorksCLIENT: Auburn, WA Driller: Boretec Boring Completed: 4/4/2013 Exhibit: Elevations taken from King County iMAP A-4 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. SA M P L E N U M B E R RE C O V E R Y ( I n . ) ELEVATION (Ft.)PE R C E N T F I N E S WA T E R CO N T E N T ( % ) FI E L D T E S T RE S U L T S WA T E R L E V E L OB S E R V A T I O N S Approximate Surface Elev: 50 (Ft.) +/- SA M P L E T Y P E DE P T H ( F t . ) 25 30 35 40 0.6 2.0 10.0 16.5 7.5" CONCRETE FILL - GRAVELLY SAND (SP), with silt, brown, medium dense, moist SILTY SAND (SM), grayish-brown, loose, moist to wet (mottled) sandy silt interbeds observed becomes wet very loose POORLY GRADED SAND (SP), trace silt and gravel, grayish-brown, loose, wet sandy silt interbeds observed grayish-black Boring Terminated at 16.5 Feet S-1 S-2 S-3 S-4 S-5 14 13 12 12 13 49.5+/- 48+/- 40+/- 33.5+/- 4-4-3 N=7 1-2-1 N=3 2-2-3 N=5 4-4-4 N=8 2-3-6 N=9 See Exhibit A-2 Hammer Type: Rope & CatheadStratification lines are approximate. In-situ, the transition may be gradual. LOCATION DEPTH GR A P H I C L O G TH I S B O R I N G L O G I S N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . D Street NE Auburn, Washington SITE: 4.5' While Drilling WATER LEVEL OBSERVATIONS PROJECT: D Street NE Improvements Page 1 of 1 Advancement Method: Hollow Stem Auger Abandonment Method: Borings backfilled with bentonite chips upon completion 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington Notes: Project No.: 81135017 Drill Rig: EC85 Boring Started: 4/4/2013 BORING LOG NO. B-2 City of Auburn Department of Public WorksCLIENT: Auburn, WA Driller: Boretec Boring Completed: 4/4/2013 Exhibit: Elevations taken from King County iMAP A-5 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. SA M P L E N U M B E R RE C O V E R Y ( I n . ) ELEVATION (Ft.)PE R C E N T F I N E S WA T E R CO N T E N T ( % ) FI E L D T E S T RE S U L T S WA T E R L E V E L OB S E R V A T I O N S Approximate Surface Elev: 50 (Ft.) +/- SA M P L E T Y P E DE P T H ( F t . ) 5 10 15 20 0.5 1.5 4.5 6.5 11.5 6.5" CONCRETE FILL - GRAVELLY SAND (SP), with silt, brown, medium dense, moist SILTY SAND (SM), grayish-brown, loose to medium dense, moist (mottled) sandy silt interbeds observed SANDY SILT (ML), grayish-brown, very soft, wet silty sand interbeds observed SILTY SAND (SM), grayish-brown, loose, wet sandy silt interbeds observed POORLY GRADED SAND (SP), trace silt, grayish-black, loose, wet Boring Terminated at 11.5 Feet S-1 S-2 S-3 S-4 9 10 12 12 49.5+/- 48.5+/- 45.5+/- 43.5+/- 38.5+/- 9-5-5 N=10 1-1-1 N=2 3-3-3 N=6 2-3-4 N=7 See Exhibit A-2 Hammer Type: Rope & CatheadStratification lines are approximate. In-situ, the transition may be gradual. LOCATION DEPTH GR A P H I C L O G TH I S B O R I N G L O G I S N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . D Street NE Auburn, Washington SITE: 4.5' While Drilling WATER LEVEL OBSERVATIONS PROJECT: D Street NE Improvements Page 1 of 1 Advancement Method: Hollow Stem Auger Abandonment Method: Borings backfilled with bentonite chips upon completion 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington Notes: Project No.: 81135017 Drill Rig: EC85 Boring Started: 4/4/2013 BORING LOG NO. B-3 City of Auburn Department of Public WorksCLIENT: Auburn, WA Driller: Boretec Boring Completed: 4/4/2013 Exhibit: Elevations taken from King County iMAP A-6 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. SA M P L E N U M B E R RE C O V E R Y ( I n . ) ELEVATION (Ft.)PE R C E N T F I N E S WA T E R CO N T E N T ( % ) FI E L D T E S T RE S U L T S WA T E R L E V E L OB S E R V A T I O N S Approximate Surface Elev: 50 (Ft.) +/- SA M P L E T Y P E DE P T H ( F t . ) 5 10 15 20 0.5 2.0 9.5 16.5 6.5" CONCRETE FILL - GRAVELLY SAND (SP), with silt, brown, medium dense, moist SILTY SAND (SM), grayish-brown, medium dense, moist to wet gravel in tip grayish-brown to black, loose, sandy silt interbeds observed becomes wet trace gravel and organics POORLY GRADED SAND (SP), trace silt, brown to black, loose, wet sandy silt interbeds observed trace silt and gravel, black, medium dense, wet Boring Terminated at 16.5 Feet S-1 S-2 S-3 S-4 S-5 4 12 13 14 14 49.5+/- 48+/- 40.5+/- 33.5+/- 20-14-11 N=25 2-3-4 N=7 2-2-3 N=5 4-4-4 N=8 3-6-7 N=13 See Exhibit A-2 Hammer Type: Rope & CatheadStratification lines are approximate. In-situ, the transition may be gradual. LOCATION DEPTH GR A P H I C L O G TH I S B O R I N G L O G I S N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . D Street NE Auburn, Washington SITE: 5' While Drilling WATER LEVEL OBSERVATIONS PROJECT: D Street NE Improvements Page 1 of 1 Advancement Method: Hollow Stem Auger Abandonment Method: Borings backfilled with bentonite chips upon completion 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington Notes: Project No.: 81135017 Drill Rig: EC85 Boring Started: 4/4/2013 BORING LOG NO. B-4 City of Auburn Department of Public WorksCLIENT: Auburn, WA Driller: Boretec Boring Completed: 4/4/2013 Exhibit: Elevations taken from King County iMAP A-7 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. SA M P L E N U M B E R RE C O V E R Y ( I n . ) ELEVATION (Ft.)PE R C E N T F I N E S WA T E R CO N T E N T ( % ) FI E L D T E S T RE S U L T S WA T E R L E V E L OB S E R V A T I O N S Approximate Surface Elev: 50 (Ft.) +/- SA M P L E T Y P E DE P T H ( F t . ) 5 10 15 20 0.6 2.0 5.0 6.5" CONCRETE FILL - GRAVELLY SAND (SP), with silt, brown, medium dense, moist SILTY SAND (SM), grayish-brown, medium dense, moist POORLY GRADED SAND WITH SILT (SP-SM), trace gravel, brown to black, loose, wet POORLY GRADED SAND (SP), trace silt and gravel, brown to black, loose, wet bentonite slurry added down auger flights POORLY GRADED SAND WITH SILT (SP-SM), brown to black, loose to medium dense, wet sandy silt laminations observed S-1 S-2 S-3 S-4 S-5 6 12 13 12 11 49.5+/- 48+/- 45+/- 14-9-9 N=18 3-3-4 N=7 4-3-5 N=8 4-5-4 N=9 3-5-6 N=11 See Exhibit A-2 Hammer Type: Rope & CatheadStratification lines are approximate. In-situ, the transition may be gradual. LOCATION DEPTH GR A P H I C L O G TH I S B O R I N G L O G I S N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . D Street NE Auburn, Washington SITE: 5' While Drilling WATER LEVEL OBSERVATIONS PROJECT: D Street NE Improvements Page 1 of 2 Advancement Method: Hollow Stem Auger Abandonment Method: Borings backfilled with bentonite chips upon completion 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington Notes: Project No.: 81135017 Drill Rig: EC85 Boring Started: 4/4/2013 BORING LOG NO. B-5 City of Auburn Department of Public WorksCLIENT: Auburn, WA Driller: Boretec Boring Completed: 4/4/2013 Exhibit: Elevations taken from King County iMAP A-8 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. SA M P L E N U M B E R RE C O V E R Y ( I n . ) ELEVATION (Ft.)PE R C E N T F I N E S WA T E R CO N T E N T ( % ) FI E L D T E S T RE S U L T S WA T E R L E V E L OB S E R V A T I O N S Approximate Surface Elev: 50 (Ft.) +/- SA M P L E T Y P E DE P T H ( F t . ) 5 10 15 20 26.5 POORLY GRADED SAND WITH SILT (SP-SM), trace gravel, brown to black, loose, wet (continued) POORLY GRADED SAND (SP), trace silt, brown to black, medium dense, wet trace silt and gravel, black, sandy silt laminations observed Boring Terminated at 26.5 Feet S-6 S-7 12 12 23.5+/- 5-6-9 N=15 5-11-12 N=23 See Exhibit A-2 Hammer Type: Rope & CatheadStratification lines are approximate. In-situ, the transition may be gradual. LOCATION DEPTH GR A P H I C L O G TH I S B O R I N G L O G I S N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . D Street NE Auburn, Washington SITE: 5' While Drilling WATER LEVEL OBSERVATIONS PROJECT: D Street NE Improvements Page 2 of 2 Advancement Method: Hollow Stem Auger Abandonment Method: Borings backfilled with bentonite chips upon completion 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington Notes: Project No.: 81135017 Drill Rig: EC85 Boring Started: 4/4/2013 BORING LOG NO. B-5 City of Auburn Department of Public WorksCLIENT: Auburn, WA Driller: Boretec Boring Completed: 4/4/2013 Exhibit: Elevations taken from King County iMAP A-8 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. SA M P L E N U M B E R RE C O V E R Y ( I n . ) ELEVATION (Ft.)PE R C E N T F I N E S WA T E R CO N T E N T ( % ) FI E L D T E S T RE S U L T S WA T E R L E V E L OB S E R V A T I O N S Approximate Surface Elev: 50 (Ft.) +/- SA M P L E T Y P E DE P T H ( F t . ) 25 30 35 40 0.5 2.0 7.0 16.5 6.5" CONCRETE FILL - GRAVELLY SAND (SP), with silt, brown, medium dense, moist SILTY SAND (SM), grayish-brown, medium dense, moist (mottled) sandy silt interbeds observed gravel in tip becomes wet SILTY CLAY (CL-ML), with sand, gray, medium stiff, wet SANDY SILT (ML), with clay, gray, medium stiff, wet trace organics SILTY CLAY (CL-ML), with sand, grayish-brown, soft, wet Boring Terminated at 16.5 Feet S-1 S-2 S-3 S-4 S-5 11 13 13 11 13 49.5+/- 48+/- 43+/- 33.5+/- 7-7-8 N=15 1-1-1 N=2 1-1-3 N=4 2-2-2 N=4 1-1-1 N=2 See Exhibit A-2 Hammer Type: Rope & CatheadStratification lines are approximate. In-situ, the transition may be gradual. LOCATION DEPTH GR A P H I C L O G TH I S B O R I N G L O G I S N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . D Street NE Auburn, Washington SITE: 5' While Drilling WATER LEVEL OBSERVATIONS PROJECT: D Street NE Improvements Page 1 of 1 Advancement Method: Hollow Stem Auger Abandonment Method: Borings backfilled with bentonite chips upon completion 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington Notes: Project No.: 81135017 Drill Rig: EC85 Boring Started: 4/4/2013 BORING LOG NO. B-6 City of Auburn Department of Public WorksCLIENT: Auburn, WA Driller: Boretec Boring Completed: 4/4/2013 Exhibit: Elevations taken from King County iMAP A-9 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. SA M P L E N U M B E R RE C O V E R Y ( I n . ) ELEVATION (Ft.)PE R C E N T F I N E S WA T E R CO N T E N T ( % ) FI E L D T E S T RE S U L T S WA T E R L E V E L OB S E R V A T I O N S Approximate Surface Elev: 50 (Ft.) +/- SA M P L E T Y P E DE P T H ( F t . ) 5 10 15 20 0.6 2.0 5.5 16.5 6.75" CONCRETE FILL - GRAVELLY SAND (SP), with silt, brown, medium dense, moist SILTY SAND (SM), grayish-brown, loose, moist (mottled) sandy silt interbeds observed SANDY SILT (ML), with clay, gray, soft, wet trace organics CLAYEY SILT (ML), with sand, grayish-brown, soft, wet silty sand interbeds observed gray, trace organics Boring Terminated at 16.5 Feet S-1 S-2 S-3 S-4 S-5 12 12 12 14 14 49.5+/- 48+/- 44.5+/- 33.5+/- 4-4-3 N=7 1-1-1 N=2 2-1-2 N=3 1-1-2 N=3 1-1-1 N=2 See Exhibit A-2 Hammer Type: Rope & CatheadStratification lines are approximate. In-situ, the transition may be gradual. LOCATION DEPTH GR A P H I C L O G TH I S B O R I N G L O G I S N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . D Street NE Auburn, Washington SITE: 5' While Drilling WATER LEVEL OBSERVATIONS PROJECT: D Street NE Improvements Page 1 of 1 Advancement Method: Hollow Stem Auger Abandonment Method: Borings backfilled with bentonite chips upon completion 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington Notes: Project No.: 81135017 Drill Rig: EC85 Boring Started: 4/5/2013 BORING LOG NO. B-7 City of Auburn Department of Public WorksCLIENT: Auburn, WA Driller: Boretec Boring Completed: 4/5/2013 Exhibit: Elevations taken from King County iMAP A-10 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. SA M P L E N U M B E R RE C O V E R Y ( I n . ) ELEVATION (Ft.)PE R C E N T F I N E S WA T E R CO N T E N T ( % ) FI E L D T E S T RE S U L T S WA T E R L E V E L OB S E R V A T I O N S Approximate Surface Elev: 50 (Ft.) +/- SA M P L E T Y P E DE P T H ( F t . ) 5 10 15 20 0.5 1.8 5.5 11.5 6.5" CONCRETE FILL - GRAVELLY SAND (SP), with silt, brown, medium dense, moist SILTY SAND (SM), brown to black, loose to medium dense, moist SANDY SILT (ML), grayish-brown, soft, wet CLAYEY SILT (ML), with sand, grayish-brown, soft, wet silty sand interbeds observed CLAYEY SILT (ML), with sand, gray, soft, wet Boring Terminated at 11.5 Feet S-1 S-2 S-3 S-4 8 12 12 7 49.5+/- 48.5+/- 44.5+/- 38.5+/- 7-4-3 N=7 2-2-1 N=3 1-1-1 N=2 1-1-1 N=2 See Exhibit A-2 Hammer Type: Rope & CatheadStratification lines are approximate. In-situ, the transition may be gradual. LOCATION DEPTH GR A P H I C L O G TH I S B O R I N G L O G I S N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . D Street NE Auburn, Washington SITE: 5' While Drilling WATER LEVEL OBSERVATIONS PROJECT: D Street NE Improvements Page 1 of 1 Advancement Method: Hollow Stem Auger Abandonment Method: Borings backfilled with bentonite chips upon completion 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington Notes: Project No.: 81135017 Drill Rig: EC85 Boring Started: 4/5/2013 BORING LOG NO. B-8 City of Auburn Department of Public WorksCLIENT: Auburn, WA Driller: Boretec Boring Completed: 4/5/2013 Exhibit: Elevations taken from King County iMAP A-11 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. SA M P L E N U M B E R RE C O V E R Y ( I n . ) ELEVATION (Ft.)PE R C E N T F I N E S WA T E R CO N T E N T ( % ) FI E L D T E S T RE S U L T S WA T E R L E V E L OB S E R V A T I O N S Approximate Surface Elev: 50 (Ft.) +/- SA M P L E T Y P E DE P T H ( F t . ) 5 10 15 20 0.5 1.8 5.0 16.5 6.5" CONCRETE FILL - GRAVELLY SAND (SP), with silt, brown, medium dense, moist SILTY SAND (SM), grayish-brown, loose, moist (mottled) sandy silt interbeds observed SANDY SILT (ML), with clay, grayish-brown, soft, wet silty sand interbeds observed medium stiff CLAYEY SILT (ML), with sand, gray, soft, wet silty sand interbeds observed Boring Terminated at 16.5 Feet S-1 S-2 S-3 S-4 S-5 12 13 13 12 12 49.5+/- 48.5+/- 45+/- 33.5+/- 5-4-3 N=7 1-1-2 N=3 4-3-2 N=5 1-1-1 N=2 1-1-1 N=2 See Exhibit A-2 Hammer Type: Rope & CatheadStratification lines are approximate. In-situ, the transition may be gradual. LOCATION DEPTH GR A P H I C L O G TH I S B O R I N G L O G I S N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . D Street NE Auburn, Washington SITE: 5' While Drilling WATER LEVEL OBSERVATIONS PROJECT: D Street NE Improvements Page 1 of 1 Advancement Method: Hollow Stem Auger Abandonment Method: Borings backfilled with bentonite chips upon completion 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington Notes: Project No.: 81135017 Drill Rig: EC85 Boring Started: 4/5/2013 BORING LOG NO. B-9 City of Auburn Department of Public WorksCLIENT: Auburn, WA Driller: Boretec Boring Completed: 4/5/2013 Exhibit: Elevations taken from King County iMAP A-12 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. SA M P L E N U M B E R RE C O V E R Y ( I n . ) ELEVATION (Ft.)PE R C E N T F I N E S WA T E R CO N T E N T ( % ) FI E L D T E S T RE S U L T S WA T E R L E V E L OB S E R V A T I O N S Approximate Surface Elev: 50 (Ft.) +/- SA M P L E T Y P E DE P T H ( F t . ) 5 10 15 20 0.3 0.8 1.3 1.9 4.0 4" ASPHALT CONCRETE FILL - POORLY GRADED GRAVEL WITH SAND (GP), grayish-brown, moist FILL - POORLY GRADED SAND WITH GRAVEL (SP), brown, medium dense, moist 6.5"CONCRETE (SP) FILL - POORLY GRADED GRAVEL WITH SILT AND SAND (GP-GM), brown, medium dense, moist CLAYEY SILT (ML), with sand, grayish-brown, soft, wet (mottled) silty sand interbeds observed gray, medium stiff, silty sand interbeds observed SANDY SILT (ML), gray, soft, silty sand interbeds observed S-1 S-2 S-3 S-4 S-5 6 12 14 12 13 51+/- 50.5+/- 50+/- 49.5+/- 47.5+/- 15-9-12 N=21 1-1-2 N=3 1-1-1 N=2 2-3-1 N=4 1-1-1 N=2 See Exhibit A-2 Hammer Type: Rope & CatheadStratification lines are approximate. In-situ, the transition may be gradual. LOCATION DEPTH GR A P H I C L O G TH I S B O R I N G L O G I S N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . D Street NE Auburn, Washington SITE: 7' While Drilling WATER LEVEL OBSERVATIONS PROJECT: D Street NE Improvements Page 1 of 2 Advancement Method: Hollow Stem Auger Abandonment Method: Borings backfilled with bentonite chips upon completion 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington Notes: Project No.: 81135017 Drill Rig: EC85 Boring Started: 4/5/2013 BORING LOG NO. B-10 City of Auburn Department of Public WorksCLIENT: Auburn, WA Driller: Boretec Boring Completed: 4/5/2013 Exhibit: Elevations taken from King County iMAP A-13 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. SA M P L E N U M B E R RE C O V E R Y ( I n . ) ELEVATION (Ft.)PE R C E N T F I N E S WA T E R CO N T E N T ( % ) FI E L D T E S T RE S U L T S WA T E R L E V E L OB S E R V A T I O N S Approximate Surface Elev: 51.5 (Ft.) +/- SA M P L E T Y P E DE P T H ( F t . ) 5 10 15 20 26.5 CLAYEY SILT (ML), with sand, grayish-brown, soft, wet (mottled) silty sand interbeds observed (continued) CLAYEY SILT (ML), with sand, gray, soft, wet silty sand interbeds observed SILTY SAND (SM), gray to black, loose, wet sandy silt interbeds observed Boring Terminated at 26.5 Feet S-6 S-7 14 13 25+/- 1-1-1 N=2 1-1-6 N=7 See Exhibit A-2 Hammer Type: Rope & CatheadStratification lines are approximate. In-situ, the transition may be gradual. LOCATION DEPTH GR A P H I C L O G TH I S B O R I N G L O G I S N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . D Street NE Auburn, Washington SITE: 7' While Drilling WATER LEVEL OBSERVATIONS PROJECT: D Street NE Improvements Page 2 of 2 Advancement Method: Hollow Stem Auger Abandonment Method: Borings backfilled with bentonite chips upon completion 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington Notes: Project No.: 81135017 Drill Rig: EC85 Boring Started: 4/5/2013 BORING LOG NO. B-10 City of Auburn Department of Public WorksCLIENT: Auburn, WA Driller: Boretec Boring Completed: 4/5/2013 Exhibit: Elevations taken from King County iMAP A-13 See Exhibit A-3 for description of field procedures. See Appendix B for description of laboratory procedures and additional data (if any). See Appendix C for explanation of symbols and abbreviations. SA M P L E N U M B E R RE C O V E R Y ( I n . ) ELEVATION (Ft.)PE R C E N T F I N E S WA T E R CO N T E N T ( % ) FI E L D T E S T RE S U L T S WA T E R L E V E L OB S E R V A T I O N S Approximate Surface Elev: 51.5 (Ft.) +/- SA M P L E T Y P E DE P T H ( F t . ) 25 30 35 40 81135017 APPENDIX B LABORATORY TESTING PROCEDURES, CLASSIFICATIONS, AND RESULTS 81135017 LABORATORY TESTING PROCEDURES The following paragraphs describe our procedures associated with the laboratory tests that we conducted for this project. Our test results are enclosed in this appendix and/or are shown on the exploration logs contained in Appendix A. As part of our testing program, the samples were examined in our laboratory and classified in accordance with the attached General Notes or the Unified Soil Classification System (USCS), based on the texture and plasticity of the soil. A brief description of the USCS is included with this appendix. Visual Classification Procedures Visual soil classifications were conducted on all samples in the field and on selected samples in our laboratory. All soils were classified in general accordance with the United Soil Classification System, which includes color, relative moisture content, primary soil type (based on grain size), and any accessory soil types. The resulting soil classifications are presented on the exploration logs contained in Appendix A. Moisture Content Determination Procedures Moisture content determinations were performed on representative samples to aid in identification and correlation of soil types. All determinations were made in general accordance with ASTM: D-2216. The results of these tests are shown on the exploration logs contained in Appendix A. Grain Size Analysis Procedures A grain size analysis indicates the range of soil particle diameters included in a particular sample. Grain size analyses were performed on representative samples in general accordance with ASTM: D-422. The results of these tests are presented on the enclosed grain-size distribution graphs and were used in soil classifications shown on the exploration logs. Atterberg Limit Determination Procedures Atterberg limits are used primarily for classifying and indexing cohesive soils. The liquid and plastic limits, which are defined as the moisture contents of a cohesive soil at arbitrarily established limits for liquid and plastic behavior, respectively, were determined for selected samples in general accordance with ASTM: D-423 and ASTM: D-414. The results of these tests are presented on the enclosed Atterberg limit graphs and on the exploration logs contained in Appendix A. 81135017 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0.0010.010.1110100 6 16 20 30 40 501.5 2006810 74.30.0 14 LL PLPI %Clay%Silt 413/4 1/2 60 fine HYDROMETERU.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS D100 CcCu SILT OR CLAY 4 %Sand%GravelD30D10 B-2 4.75B-2 2.5 GRAIN SIZE IN MILLIMETERS PE R C E N T F I N E R B Y W E I G H T coarse fine 3/8 3 100 14032 COBBLES GRAVEL SAND USCS Classification 25.7 D60 coarse medium 2.5 Boring ID Depth Boring ID Depth GRAIN SIZE DISTRIBUTION ASTM D422 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington PROJECT NUMBER: 81135017PROJECT: D Street NE Improvements SITE: D Street NE Auburn, Washington CLIENT: City of Auburn Department of Public Works Auburn, WA EXHIBIT: B-1 LA B O R A T O R Y T E S T S A R E N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . G R A I N S I Z E : U S C S - 2 8 1 1 3 5 0 1 7 , B O R I N G L O G S . G P J F E N C E P R O J E C T 1 - 8 - 1 3 . G P J 5 / 3 / 1 3 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0.0010.010.1110100 6 16 20 30 40 501.5 2006810 6.01.90.114 14 LL PLPI %Clay%Silt 413/4 1/2 60 fine HYDROMETERU.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS 1.36 D100 CcCu SILT OR CLAY 4 %Sand%GravelD30D10 B-4 0.2360.36212.5B-4 3.175.0 GRAIN SIZE IN MILLIMETERS PE R C E N T F I N E R B Y W E I G H T coarse fine 3/8 3 100 14032 COBBLES GRAVEL SAND USCS Classification 92.1 D60 coarse medium 5.0 Boring ID Depth Boring ID Depth GRAIN SIZE DISTRIBUTION ASTM D422 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington PROJECT NUMBER: 81135017PROJECT: D Street NE Improvements SITE: D Street NE Auburn, Washington CLIENT: City of Auburn Department of Public Works Auburn, WA EXHIBIT: B-1 LA B O R A T O R Y T E S T S A R E N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . G R A I N S I Z E : U S C S - 2 8 1 1 3 5 0 1 7 , B O R I N G L O G S . G P J F E N C E P R O J E C T 1 - 8 - 1 3 . G P J 5 / 3 / 1 3 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0.0010.010.1110100 6 16 20 30 40 501.5 2006810 54.20.3 14 LL PLPI %Clay%Silt 413/4 1/2 60 fine HYDROMETERU.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS D100 CcCu SILT OR CLAY 4 %Sand%GravelD30D10 B-7 0.0849.5B-7 2.5 GRAIN SIZE IN MILLIMETERS PE R C E N T F I N E R B Y W E I G H T coarse fine 3/8 3 100 14032 COBBLES GRAVEL SAND USCS Classification 45.5 D60 coarse medium 2.5 Boring ID Depth Boring ID Depth GRAIN SIZE DISTRIBUTION ASTM D422 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington PROJECT NUMBER: 81135017PROJECT: D Street NE Improvements SITE: D Street NE Auburn, Washington CLIENT: City of Auburn Department of Public Works Auburn, WA EXHIBIT: B-1 LA B O R A T O R Y T E S T S A R E N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . G R A I N S I Z E : U S C S - 2 8 1 1 3 5 0 1 7 , B O R I N G L O G S . G P J F E N C E P R O J E C T 1 - 8 - 1 3 . G P J 5 / 3 / 1 3 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0.0010.010.1110100 6 16 20 30 40 501.5 2006810 10.01.5 14 LL PLPI %Clay%Silt 413/4 1/2 60 fine HYDROMETERU.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS 1.45 D100 CcCu SILT OR CLAY 4 %Sand%GravelD30D10 B-8 0.1770.28812.5B-8 3.842.5 GRAIN SIZE IN MILLIMETERS PE R C E N T F I N E R B Y W E I G H T coarse fine 3/8 3 100 14032 COBBLES GRAVEL SAND USCS Classification 88.5 D60 coarse medium 2.5 Boring ID Depth Boring ID Depth GRAIN SIZE DISTRIBUTION ASTM D422 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington PROJECT NUMBER: 81135017PROJECT: D Street NE Improvements SITE: D Street NE Auburn, Washington CLIENT: City of Auburn Department of Public Works Auburn, WA EXHIBIT: B-1 LA B O R A T O R Y T E S T S A R E N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . G R A I N S I Z E : U S C S - 2 8 1 1 3 5 0 1 7 , B O R I N G L O G S . G P J F E N C E P R O J E C T 1 - 8 - 1 3 . G P J 5 / 3 / 1 3 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0.0010.010.1110100 6 16 20 30 40 501.5 2006810 50.10.0 14 LL PLPI %Clay%Silt 413/4 1/2 60 fine HYDROMETERU.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS D100 CcCu SILT OR CLAY 4 %Sand%GravelD30D10 B-9 0.0944.75B-9 2.5 GRAIN SIZE IN MILLIMETERS PE R C E N T F I N E R B Y W E I G H T coarse fine 3/8 3 100 14032 COBBLES GRAVEL SAND USCS Classification 49.9 D60 coarse medium 2.5 Boring ID Depth Boring ID Depth GRAIN SIZE DISTRIBUTION ASTM D422 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington PROJECT NUMBER: 81135017PROJECT: D Street NE Improvements SITE: D Street NE Auburn, Washington CLIENT: City of Auburn Department of Public Works Auburn, WA EXHIBIT: B-1 LA B O R A T O R Y T E S T S A R E N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . G R A I N S I Z E : U S C S - 2 8 1 1 3 5 0 1 7 , B O R I N G L O G S . G P J F E N C E P R O J E C T 1 - 8 - 1 3 . G P J 5 / 3 / 1 3 0 10 20 30 40 50 60 0 20 40 60 80 100 CH or OH CL or O L ML or OL MH or OH PLPI 7.5 Boring ID Depth DescriptionFines P L A S T I C I T Y I N D E X LIQUID LIMIT "U " Lin e "A " L i n e 36288 LL USCS B-6 ATTERBERG LIMITS RESULTS ASTM D4318 21905 64th Ave. W, Suite 100 Mountlake Terrace, Washington PROJECT NUMBER: 81135017PROJECT: D Street NE Improvements SITE: D Street NE Auburn, Washington CLIENT: City of Auburn Department of Public Works Auburn, WA EXHIBIT: B-1 LA B O R A T O R Y T E S T S A R E N O T V A L I D I F S E P A R A T E D F R O M O R I G I N A L R E P O R T . A T T E R B E R G L I M I T S 8 1 1 3 5 0 1 7 , B O R I N G L O G S . G P J F E N C E P R O J E C T 1 - 8 - 1 3 . G P J 5 / 3 / 1 3 CL-ML 81135017 APPENDIX C SUPPLEMENTAL INFORMATION Map created with Map created with Map created with Map created with Map created with Map created with Map created with Map created with Map created with TOPO!®TOPO!®TOPO!®TOPO!®TOPO!®TOPO!®TOPO!®TOPO!®TOPO!® ©2010 National Geographic ©2010 National Geographic ©2010 National Geographic ©2010 National Geographic ©2010 National Geographic ©2010 National Geographic ©2010 National Geographic ©2010 National Geographic ©2010 National Geographic Excerpt from 1994 USGS map titled "Auburn, WA" (contour interval = 20 feet) 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 miles 0.0 0.5 1.0 km 04/25/13 TNMN 16½ Qvt Qal m Qal Qvi 5 12 4 t h A S E S 277th S t 11 6 t h A v 15th StNW SR 1 6 7 R a m p . Excerptfrom2007"GeologicMapofKingCounty"byGeoMapNorthwest PROJECTSITE Excerpt from King County iMap (April 2013) The information included on this map has been compiled by King County staff from a variety of sources and is subject to change without notice. King County makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a survey product. King County shall not be liable for any general, special, indirect, incidental, or consequential damages including, but not limited to, lost revenues or lost profits resulting from the use or misuse of the information contained on this map. Any sale of this map or information on this map is prohibited except by written permission of King County. Date: 4/25/2013 Source: King County iMAP - Sensitive Areas (http://www.metrokc.gov/GIS/iMAP) PROJECTSITE Excerpt from King County iMap (April 2013) The information included on this map has been compiled by King County staff from a variety of sources and is subject to change without notice. King County makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a survey product. King County shall not be liable for any general, special, indirect, incidental, or consequential damages including, but not limited to, lost revenues or lost profits resulting from the use or misuse of the information contained on this map. Any sale of this map or information on this map is prohibited except by written permission of King County. Date: 4/25/2013 Source: King County iMAP - Sensitive Areas (http://www.metrokc.gov/GIS/iMAP) PROJECT INFORMATION Project Name: Project Number: Notes: Date: W 18 200,000 R85% ZR -1.037 So0.5 po 4.2 pt 2.7 p 1.5 MaterialStructural CoefficientDrainage CoefficientResilient Modulus Asphalt0.44 Aggregate Base0.131.030,000 Subbase 0.1 0.9 20,000 Subgrade 5,000 ItemMin Required Actual ProvidedActual Structural Number Asphalt (in)3.4 4 1.76 Aggregate Base (in)0.2 4 0.52 Subbase (in)9.1 10 0.90 Asphalt SN1.51 1.76 OK Aggregate Base SN1.78 2.28 OK Total SN 3.1 3.18 OK Click after any change Item Inches Feet Notes/Designation Asphalt 4 inches 0.33 feetWSDOT HMA-1/2 Aggregate Base 4 inches 0.33 feetWSDOT CSBC Subbase 10 inches 0.83 feetWSDOT Ballast or CRC Total Thickness 18 inches 1.5 feet Existing section T=19" Summary Number of 18 kip equivalent single axle loads (ESALs) Reliability Standard normal deviate (function of reliability) Standard deviation Initial Serviceability Final serviceability Allowable serviceability loss at end of design life Asphalt Section Design and Checks Material Properties and Drainage Traffic, Reliability, and Serviceability 1993 AASHTO Flexible Design Method D Street Utility Improvements 81135017 Trial 5a May 1, 2013