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Home My WebLink AboutPZ - Geotech Eval w-Groundwater Monitoring Test Pit: TP-1 TP-2 TP-4 TP-8 Feet Below Ground Surface Date 3/15/2021 >11.8 >13 >11.2 >13.8 4/12/2021 >11.8 >13 >11.2 >13.8 5/19/2021 >11.8 >13 >11.2 >13.8 6/15/2021 >11.8 >13 >11.2 >13.8 7/19/2021 >11.8 >13 >11.2 >13.8 8/16/2021 >11.8 >13 >11.2 >13.8 9/16/2021 >11.8 >13 >11.2 >13.8 10/19/2021 >11.8 >13 >11.2 >13.8 11/23/2021 >11.8 >13 >11.2 >13.8 3/25/2022 >11.8 >13 >11.2 >13.8 Table 1 ALLWEST Ground Water Monitoring Gramercy Commons (Wells Avenue Multifamily) Meridian, Idaho 255 N. Linder Road, Suite 100 Client Name: Intermountain Pacific, LLC Meridian, Idaho 83642 Project No.: 520-448G Phone: 208-895-7898 Fax: 208-898-3959 Date: March 2022 V-0, 7 I n � �IJ o IJ ■ i f � �IJ � ■ - # J� Aw r yt ti r Upd � y ' . Apo o � r rp r �4_4kCIOINO 0 IL n - Legend p Approximate location of test pit observed by ALLWEST. Slotted PVC pipe installed in test pit. Figure A-2 - Exploration Location Plan ALLWEST Geotechnical Evaluation Wells Ave Multifamily Development Meridain, Idaho 255 N. Linder Road, Suite 100 Client: Intermountian Pacific, LLC Meridian, Idaho 83642 Project No.: 520-448G Phone: (208) 895-7898 Fax: (208) 898-3959 Date: February 2021 10/11/2024 Time of testing 12:36 PM Sites Tested: TP- 1 :12 feet to bottom (from base)of pipe no water TP-2 :12 feet to bottom(from base) of pipe no water TP-4 :10 feet to bottom(from base) of pipe no water TP-7 :12.75 feet to bottom from base)of pipe no water TP-8 :12.5 feet to bottom(from base)of pipe no water 10/25/2024 Time of testing 11:20 AM Sites Tested: TP- 1 :12 feet to bottom (from base)of pipe no water TP-2 :12 feet to bottom(from base) of pipe no water TP-4 :10 feet to bottom(from base) of pipe no water TP-7 :12.75 feet to bottom from base)of pipe no water TP-8 :12.5 feet to bottom(from base)of pipe no water 11/8/2024 Time of testing 10:26 AM Sites Tested: TP- 1 :12 feet to bottom (from base)of pipe no water TP-2 :12 feet to bottom(from base) of pipe no water TP-4 :10 feet to bottom(from base) of pipe no water TP-7 :12.75 feet to bottom from base)of pipe no water TP-8 :12.5 feet to bottom(from base)of pipe no water 11/20/2024 Time of testing 1:56 PM Sites Tested: TP- 1 :12 feet to bottom (from base)of pipe no water TP-2 :12 feet to bottom(from base) of pipe no water TP-4 :10 feet to bottom(from base) of pipe no water TP-7 :12.75 feet to bottom from base)of pipe no water TP-8 :12.5 feet to bottom(from base)of pipe no water 12/5/2024 Time of testing 3:56 PM Sites Tested: TP- 1 :12 feet to bottom (from base)of pipe no water TP-2 :12 feet to bottom(from base) of pipe no water TP-4 :10 feet to bottom(from base) of pipe no water TP-7 :12.75 feet to bottom from base)of pipe no water TP-8 :12.5 feet to bottom(from base)of pipe no water 12/20/2024 Time of testing 11:30 AM Sites Tested: TP- 1 :12 feet to bottom (from base)of pipe no water TP-2 :12 feet to bottom(from base) of pipe no water TP-4 :10 feet to bottom(from base) of pipe no water TP-7 :12.75 feet to bottom from base)of pipe no water TP-8 :12.5 feet to bottom(from base)of pipe no water 1/8/2025 Time of testing 2 PM Sites Tested: TP- 1 :12 feet to bottom (from base)of pipe no water TP-2 :12 feet to bottom(from base) of pipe no water TP-4 :10 feet to bottom(from base) of pipe no water TP-7 :12.75 feet to bottom from base)of pipe no water TP-8 :12.5 feet to bottom(from base)of pipe no water 1/22/2025 Time of testing 3 PM Sites Tested: TP- 1 :12 feet to bottom (from base)of pipe no water TP-2 :12 feet to bottom(from base) of pipe no water TP-4 :10 feet to bottom(from base) of pipe no water TP-7 :12.75 feet to bottom from base)of pipe no water TP-8 :12.5 feet to bottom(from base)of pipe no water 2/5/2025 Time of testing 11 AM Sites Tested: TP- 1 :12 feet to bottom (from base)of pipe no water TP-2 :12 feet to bottom(from base) of pipe no water TP-4 :10 feet to bottom(from base) of pipe no water TP-7 :12.75 feet to bottom from base)of pipe no water TP-8 :12.5 feet to bottom(from base)of pipe no water 2/27/2025 Time of testing 3 PM Sites Tested: TP- 1 :12 feet to bottom (from base)of pipe no water TP-2 :12 feet to bottom(from base) of pipe no water TP-4 :10 feet to bottom(from base) of pipe no water TP-7 :12.75 feet to bottom from base)of pipe no water TP-8 :12.5 feet to bottom(from base)of pipe no water 3/3/2025 Time of testing 10 AM Sites Tested: TP- 1 :12 feet to bottom (from base)of pipe no water TP-2 :12 feet to bottom(from base) of pipe no water TP-4 :10 feet to bottom(from base) of pipe no water TP-7 :12.75 feet to bottom from base)of pipe no water TP-8 :12.5 feet to bottom(from base)of pipe no water 3/19/2025 Time of testing 1 PM Sites Tested: TP- 1 :12 feet to bottom (from base)of pipe no water TP-2 :12 feet to bottom(from base) of pipe no water TP-4 :10 feet to bottom(from base) of pipe no water TP-7 :12.75 feet to bottom from base)of pipe no water TP-8 :12.5 feet to bottom(from base)of pipe no water 4/1/2025 Time of testing 2 PM Sites Tested: TP- 1 :12 feet to bottom (from base)of pipe no water TP-2 :12 feet to bottom(from base) of pipe no water TP-4 :10 feet to bottom(from base) of pipe no water TP-7 :12.75 feet to bottom from base)of pipe no water TP-8 :12.5 feet to bottom(from base)of pipe no water I ENVIRONMENTAL TECHNICAL ALLWEST MATERIALS OTESTING I SPECIAL INSPECTION AN EMPLOYEE-OWNED COMPANY February 12, 2021 Mike Chidester Intermountain Pacific, LLC 2541 East Gala Street, Suite 310 Meridian, Idaho 83642 mikeRbristol-company c.. RE: Geotechnical Evaluation Wells Avenue Multifamily Development Meridian, Idaho ALLWEST Project No. 520-448G Mr. Chidester: ALLWEST has completed the authorized geotechnical evaluation for the proposed Wells Avenue Multifamily Development to be developed approximately 700 feet southwest of the East Gala Street and South Wells Avenue intersection in Meridian, Idaho. The purpose of this evaluation was to characterize subsurface soil conditions at the site and provide geotechnical recommendations to assist planning, design, and construction of the proposed development. Based on our evaluation,the site is suitable for the planned development. The attached report presents the results of our field evaluation, laboratory testing, and our recommendations. Once final structural and development plans are provided for our review, we can provide foundation-related recommendations in an addendum to this report. This additional service will be provided on a time-and-expense basis. We appreciate the opportunity to be of service to Intermountain Pacific, LLC. If you have any questions or need additional information, please contact us at (208) 895-7898. Sincerely, ALLWEST y��CNs F Z//Z. 14253 OF IOt�� Adrian Mascorro, P.E. ' �y� Area Manager 255 N. Linder Rd., Suite#100, Meridian, ID 83642 Phone: 208.895.7898 • Fax: 208.898.3959 Hayden, ID•Lewiston, ID•Meridian, ID•Spokane Valley,WA• Missoula, MT www.allwesttesting.com GEOTECHNICAL EVALUATION WELLS AVENUE MULTIFAMILY DEVELOPMENT MERIDIAN, IDAHO ALLWEST PROJECT NO. 520-448G February 12, 2021 Prepared for: Intermountain Pacific, LLC 2541 East Gala Street, Suite 310 Meridian, Idaho 83642 Prepared By: ALLWEST 255 North Linder Road, Suite 100 Meridian, Idaho 83642 A LWE T WWW.ALLWESTTESTING.COM TABLE OF CONTENTS ALLWEST Project No. 520-448G Wells Avenue Multifamily Development Meridian, Idaho Page 1.0 SCOPE OF SERVICES ........................................................................................2 2.0 PROJECT UNDERSTANDING.............................................................................2 3.0 FIELD EVALUATION PROCEDURES.................................................................3 4.0 SITE CONDITIONS ..............................................................................................3 4.1 General Geologic Conditions............................................................................. 3 4.2 General Soil Conditions.....................................................................................4 5.0 EXPLORATION AND SAMPLING .......................................................................4 5.1 Subsurface Soil Conditions ...............................................................................4 5.2 Subsurface Water.............................................................................................. 5 6.0 LABORATORY TESTING ....................................................................................5 7.0 CONCLUSIONS AND RECOMMENDATIONS ....................................................6 7.1 Grading and Drainage....................................................................................... 6 7.2 Site Preparation.................................................................................................6 7.3 Subgrade Stabilization ...................................................................................... 7 7.4 Excavation......................................................................................................... 8 7.5 Materials............................................................................................................ 8 7.6 Fill Placement and Compaction......................................................................... 9 7.7 Utility Trenches.................................................................................................. 9 7.8 Wet Weather Construction ................................................................................ 9 7.9 Cold Weather Construction ............................................................................. 10 7.10 Stormwater Disposal ..................................................................................... 10 7.11 Asphalt Pavements ....................................................................................... 11 8.0 ADDITIONAL RECOMMENDED SERVICES..................................................... 12 9.0 EVALUATION LIMITATIONS............................................................................. 13 Appendix A— Site Vicinity Map, Exploration Location Plan Appendix B —Test Pit Logs, Unified Soil Classification System Appendix C— Laboratory Test Results GEOTECHNICAL I ENVIRONMENTAL ALLWESTMATERIALS TESTING I SPECIAL INSPECTION AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation Wells Avenue Multifamily Development Meridian, Idaho ALLWEST has completed the geotechnical evaluation for the proposed Wells Avenue Multifamily Development planned approximately 700 feet southwest of the East Gala Street and South Wells Avenue intersection in Meridian, Idaho. The general location of the site is shown on Figure A-1 — Site Vicinity Map in Appendix A of this report. The purpose of this evaluation was to identify subsurface soil conditions at the site, and provide opinions and recommendations for the proposed development, relative to earthwork, utilities, stormwater disposal, and pavement section design. This report details the results of our field evaluation and presents recommendations to assist planning, design, and construction. 1.0 SCOPE OF SERVICES Our scope of services for the project included the following: 1) Prior to subsurface exploration, we visited the site to observe site accessibility and to pre-mark exploration locations, as required by Idaho Digline. 2) Notified Idaho Digline to locate on-site utilities, as required by Idaho state law. 3) Subcontracted a backhoe and operator to observe the excavation of 8 test pits throughout the site. 4) Visually described and classified the soils encountered within test pits in general accordance with ASTM D 2487 and ASTM D 2488, which utilizes the Unified Soil Classification System (USCS), and we logged the subsurface profiles. We obtained soil samples within select test pits. 5) Performed seepage tests within select test pits to evaluate subsurface seepage. We installed PVC pipes within select test pits for future groundwater monitoring. 6) Performed laboratory tests on select soil samples to assess some of the soil engineering properties and characteristics. 7) Reviewed the results of the field evaluation and laboratory testing, performed engineering analyses, and prepared this report with our field evaluation results, subsurface logs, and geotechnical-related opinions and recommendations. We provided our services for the project in general accordance with our geotechnical proposal (520-448P) dated November 16, 2020. 2.0 PROJECT UNDERSTANDING Based on electronic communication with you, which included an aerial image of the project location comprising of three parcels, we understand the project will consist of an approximate 7-acre multifamily development with associated infrastructure, GEOTECHNICAL I ENVIRONMENTAL ALLWESTMATERIALS TESTING I SPECIAL INSPECTION AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 520-448G Wells Avenue Multifamily Development Page 3 Meridian, Idaho stormwater disposal facilities, and asphalt-paved parking and drive-lanes. The development will consist of multiple 3- or 4-story-tall apartment buildings with elevators; as such, elevator pits will be required. Final structural and development plans were not available at the time of this report. As such, foundation-related recommendations are not included as a part of this evaluation. Once final plans are developed for our review, we can provide foundation- related recommendations for final construction, to assist structural design. Final foundation-related recommendations can be provided as an addendum to this geotechnical evaluation. Providing foundation-related recommendations were not a part of the scope of services for this report; once requested, we can provide this information on a time-and-expense basis. Depending on the final type and size of the structures, this may require additional exploration, testing, and evaluation to provide structure-specific foundation-construction recommendations. The need for additional evaluation will be determined once final structural plans are provided for our review. 3.0 FIELD EVALUATION PROCEDURES To complete this evaluation, on January 20, 2021 we observed the excavation of 8 test pits to a maximum depth of 14 feet. We did observe excavation refusal within two of the test pits within strongly cemented soils. We identified subsurface soil conditions, logged the subsurface soil profiles, and obtained soil samples for laboratory testing. We performed field seepage testing within select test pits to help evaluate subsurface soil seepage. At completion of exploration, the test pits were loosely backfilled with excavated soil approximately level with existing ground surfaces. The approximate test pit locations are shown on Figure A-2 — Exploration Location Plan in Appendix A. 4.0 SITE CONDITIONS At the time of our field exploration, the site consisted of undeveloped dirt lots with sparse surficial vegetation. The site was bordered by residential apartment buildings to the south, Mountain View High School baseball fields to the west, and commercial developments to the north and east. 4.1 General Geologic Conditions The geologic conditions at the site are mapped as Gravel of Sunrise terrace (Qsg) on the "Geologic Map of the Boise Valley and Adjoining Area, Western Snake River Plain, Idaho" (by Othberg and Stanford, 1992). Surficial soils consist of 3 to 6 feet of loess overlying sandy pebble and cobble gravel approximately 44 feet thick. This area consists of the third terrace above the floodplain. The soils encountered within test pits are generally consistent with geologic mapping. GEOTECHNICAL I ENVIRONMENTAL ALLWESTMATERIALS TESTING I SPECIAL INSPECTION AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 520-448G Wells Avenue Multifamily Development Page 4 Meridian, Idaho 4.2 General Soil Conditions The USDA Natural Resources Conservation Service (NRCS), which represents the upper 5 feet of soil profile, has mapped the soils on the site as Elijah silt loam and Abo silt loam. The parent materials are lacustrine deposits, loess, and/or alluvium consisting of loam, silt loam, clay loam, silty clay loam, fine gravelly coarse sandy loam, gravelly sand, and cemented material. The soils encountered within test pits are generally consistent with NRCS mapping. 5.0 EXPLORATION AND SAMPLING We observed the excavation of the test pits using a Case 580C backhoe with a 3-foot- wide bucket. We obtained soil samples at select depths within test pits for further identification and laboratory testing. We performed seepage testing within select test pits throughout the site. The test pit locations were identified on-site with flagged- stakes or white PVC pipes. We obtained Google Earth latitude and longitude coordinates of test pit locations with a hand-held cellular device; these coordinates can be found on individual test pit logs in the Appendix B, and should be considered accurate to the degree implied by the method used. 5.1 Subsurface Soil Conditions At the time of exploration, the site was mainly bare of vegetation and contained sparse areas with surficial vegetation. Significant roots and vegetation were not observed within the test pits. In general, the subsurface soils within the observed test pits consisted of surficial lean clay, underlain by silts and silty sands with varying thicknesses and levels of cementation, overlying silty gravels and poorly-graded gravels with varying amounts of silt. Specific descriptions of soils observed throughout our field exploration follow: Poorly-graded gravel with silt and sand (filly — At the ground surface in test pits TP-1 and -2, we observed undocumented fill soils consisting of poorly-graded gravel with silt and sand down to depths of/z to 1'/2 feet below ground. We described fill poorly-graded gravel with silt and sand as tan, medium dense, and moist. Lean clay with sand (CL) (native) — Underlying undocumented fill gravels within test pits TP-1 and -2, and at the ground surface within the other test pits, we observed native lean clay with sand (with no sand in test pits TP-7 and -8) down to depths of 1'/2 to 3 feet below ground. We described lean clays as brown, stiff, and moist. Silt with sand, sandy silt (ML) — Underlying lean clay soils, we observed silt with sand or sandy silt down to depths of 4 to 5 feet below ground. We described silt soils as brown, medium dense, and moist. GEOTECHNICAL I ENVIRONMENTAL ALLWESTMATERIALS TESTING I SPECIAL INSPECTION AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 520-448G Wells Avenue Multifamily Development Page 5 Meridian, Idaho Silty sand (SM) — Underlying the silt soils, we observed silty sand down to depths of 6 to 10 feet below ground. We described silty sand as tan to brown, dense to very dense, and moist. The silty sand soils contained varying amounts and thicknesses of weak to very strong cementation. Within test pits TP-1, -5, -6, and -8, we observed sandy silts or silts with sand underlying silty sand soils. Silty gravel with sand (GM), poorly-graded gravel with silt and sand (GP-GM) — Underlying silty sands, sandy silts, or silts with sand, we typically observed silty gravel with sand and/or poorly-graded gravel with silt and sand down 11'/2 to maximum excavation depths of up to 14 feet below ground. We described "dirty" gravels as brown, medium dense, and moist. Poorly-graded gravel with sand (GP) — Underlying the poorly-graded gravels with silt and sand within test pits TP-2 and -4, we observed poorly-graded gravel with sand to maximum excavation depths of up to 14 feet below ground. We described "clean" gravels as tan, medium dense, and moist. Detailed soil descriptions, depths, and notes are presented on individual test pit logs in Appendix B. The descriptive soil terms used on the test pit logs, and in this report, can be referenced by the USCS. A copy of the USCS is included in Appendix B. Subsurface conditions may vary between exploration locations. Such changes in subsurface conditions may not be apparent until construction, and if they change significantly from those observed, then accordingly, construction timing, plans, and costs may change. 5.2 Subsurface Water At the time of exploration, we did not encounter groundwater within test pits down to a maximum depth of 14 feet. Groundwater in the area may be influenced by irrigation, precipitation, on-site construction, and development to adjacent sites. Subsurface water will fluctuate throughout the different seasons of the year, but will most likely be affected during seasonal snow melt and irrigation seasons (March to October). We installed PVC pipes within 4 test pits for future groundwater monitoring. Groundwater monitoring should be accomplished throughout snowmelt and irrigation seasons to verify the presence or absence of groundwater on-site. 6.0 LABORATORY TESTING We performed laboratory testing to supplement field classifications and to assess some of the soil engineering properties and parameters. The laboratory tests conducted included moisture content (ASTM D 2216), gradation (ASTM D 1140), Atterberg limits (ASTM D 4318), and California bearing ratio (CBR) (ASTM D 1883). Laboratory test results are summarized in Appendix C, and are also presented on test pit logs in Appendix B. GEOTECHNICAL I ENVIRONMENTAL ALLWESTMATERIALS TESTING I SPECIAL INSPECTION AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 520-448G Wells Avenue Multifamily Development Page 6 Meridian, Idaho 7.0 CONCLUSIONS AND RECOMMENDATIONS Based on our observations, testing, and evaluation, in our opinion the site is suitable for the planned development, provided our recommendations are adhered to. The following recommendations are presented to assist with planning, design, and construction of the development, relative to earthwork, infrastructure, stormwater disposal, and asphalt pavements. These recommendations are based on our understanding of the proposed development, the conditions observed within exploration locations, laboratory test results, and engineering analysis. If the scope of construction changes, or if conditions are encountered during construction that differ from those described herein, we should be notified so we can review our recommendations and provide revisions, if necessary. Foundation-related recommendations are not provided as part of this evaluation, but can be provided as an addendum to this report, once final structural/development plans are provided for our review. 7.1 Grading and Drainage We did not review final grading plans for this development, but we anticipate site grading will consist of cuts and fills of up to 2 feet or less. We should be notified if actual site grading varies significantly from this stated information, as it may affect our recommendations herein. Final site grading should be such that surfaces slope away from development areas. 7.2 Site Preparation • Prior to conducting site grading, surficial soil containing vegetation, roots, and organics (if vegetation growth occurs prior to development) should be removed below proposed site grading fill areas, pavement areas, and any other development areas. • Loose test pit backfill will settle with time, so where any test pits are located below proposed structures or any development areas, the loose test pit backfill soil must be re-excavated its entire depth and replaced with suitably moisture- conditioned and compacted fill soil. Existing over-excavated soils can be reused to backfill the test pits, provided the soils are not overly saturated, and they can achieve the required compaction criteria, as required in section 7.6 Fill Placement and Compaction. We recommend test pit areas be accurately surveyed so that they may be located and remediated, prior to earthwork construction and development. • After site stripping, any over-excavations, loose test pit remediation, and prior to site grading, utility backfill, or roadway construction, the exposed subgrades should be proof-rolled with a minimum of 5-ton vibratory roller, or with a vibratory GEOTECHNICAL I ENVIRONMENTAL ALLWESTMATERIALS TESTING I SPECIAL INSPECTION AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 520-448G Wells Avenue Multifamily Development Page 7 Meridian, Idaho hoe-pack, to confirm subgrade stability. This will also assist in identifying any soil associated with loose test pit backfills or wet/soft soils due to precipitation. If native subgrade soil is observed to significantly deflect or pump, it should be over-excavated and replaced with properly compacted fills, or stabilized to firm, non-yielding soil as recommended in section 7.3 Subgrade Stabilization. 7.3 Subgrade Stabilization If the subgrade soils are observed to pump or deflect significantly during grading, the subgrades should be stabilized prior to fill placement. Subgrades may be stabilized using geosynthetic reinforcement in conjunction with imported granular structural fill. The required thicknesses of granular structural fill (used in conjunction with geosynthetic reinforcement)will be dependent on the construction traffic loading, which is unknown at this time. Therefore, a certain degree of trial and error may be required during construction to verify recommended stabilization section thicknesses. Geosynthetic reinforcement should consist of Tensar TX-160 or equivalent. Alternatives to Tensar TX-160 must be approved by the geotechnical engineer prior to use on site. The following recommendations are provided for subgrade stabilization using geosynthetic reinforcement. • Geosynthetic reinforcement materials should be placed on a non-disturbed subgrade with smooth surface. Loose and disturbed soil should be removed prior to placement of geosynthetic reinforcement materials. • A minimum weight 4-ounce, non-woven filter fabric should be placed on the undisturbed subgrade. The geosynthetic reinforcement should be placed directly on top of the filter fabric. The filter fabric and geosynthetic reinforcement should be unrolled in the primary direction of fill placement and should be over- lapped at least 3 feet, or follow manufacturer's recommendations. • The geosynthetic materials should be pulled taut to remove slack. • Construction equipment should not be operated directly on the geosynthetic materials. Fill should be placed from outside the excavation to create a pad to operate equipment on. We recommend a minimum of 12 to 18 inches of granular structural fill be placed over the geosynthetic reinforcement before operating construction equipment on the fill. Low-pressure, track-mounted equipment should be used to place fill over the geosynthetic reinforcement. • Granular structural fill placed directly over geosynthetic reinforcement should be properly moisture-conditioned prior to placement, and once placed, be statically rolled. This section is the "bridge" section over soft subgrades. GEOTECHNICAL I ENVIRONMENTAL ALLWESTMATERIALS TESTING I SPECIAL INSPECTION AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 520-448G Wells Avenue Multifamily Development Page 8 Meridian, Idaho • After the first "bridge" lift has been placed, the remaining fill material above the "bridge" section should be compacted to structural fill criteria in section 7.6 Fill Placement and Compaction, utilizing vibratory compaction methods. • Vibration should be discontinued if it reduces the subgrade stability. If compaction criterion is not met within the fill lift above the "bridge" section, the "bridge" section thickness is not enough, and subgrade stabilization must be attempted again with a greater "bridge" section. The geotechnical engineer or a representative of the geotechnical engineer must be on-site during subgrade stabilization to verify our recommendations are followed, and to provide additional recommendations, as needed. 7.4 Excavation Generally, excavation of on-site soil can be accomplished with typical excavation equipment. Where strong cementation is encountered, excavation may require larger excavation equipment. We recommend excavations greater than 4 feet deep be sloped no steeper than 1.5H:1 V (horizontal to vertical). Alternatively, deeper excavations may be shored or braced in accordance with Occupational Safety and Health Administration (OSHA) specifications and local codes. Regarding trench wall support, the site soil is considered Type C soil according to OSHA guidelines. Ultimately, the contractor is responsible for site safety, excavation configurations and following OSHA guidelines. 7.5 Materials Stripped soils and soils containing vegetation or debris are only suitable for use in non- structural landscape areas. Existing on-site soils may be reused as site grading fill, provided they are stockpiled separately, they meet the criteria below, and they are compacted as required in this report. Imported granular soils should be free of organics, debris and other deleterious material and meet the following criteria. Import materials should be approved by ALLWEST prior to delivery to the site. Fill Type Criteria Site Grading Fill Maximum size <_ 6 inches; 0 Retained on /4 inch sieve < 30o ; Liquid limit < 50/o Maximum size <_ 6 inches; Granular Structural Fill, Retained on 3/4-inch sieve < 30%; Granular Subbase Passing No. 200 sieve <_ 15%; Non-plastic Alternatively, meet ISPWC section 801 6 inches Maximum size <_ 1 inch; Crushed Base Course Retained on 3/4-inch sieve < 10%; Passing No. 200 sieve < 10%; Non-plastic Alternatively, meet ISPWC section 802 (Type I Maximum size 5 2 inches; Utility Trench Backfill Retained on 3/4-inch sieve < 30%; Passing No. 200 sieve <_ 10%; Non-plastic Alternatively, meet ISPWC section 305 (Type 1) GEOTECHNICAL I ENVIRONMENTAL ALLWESTMATERIALS TESTING I SPECIAL INSPECTION AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 520-448G Wells Avenue Multifamily Development Page 9 Meridian, Idaho 7.6 Fill Placement and Compaction Fill should be placed in lift thicknesses which are appropriate for the compaction equipment used. Typically, 8- to 12-inch-thick loose-lifts are appropriate for typical rubber-tire and steel-drum compaction equipment. Lift thicknesses should be reduced to 4 inches for hand-operated compaction equipment. Fill should be moisture- conditioned to within 2% of the optimum moisture content prior to placement to facilitate compaction. Fill should be compacted to the following percentages of the maximum dry density as determined by ASTM D 1557 (modified Proctor). Fill Area Compaction (0 Sub grade Proof-roll' Site Grading Fill / Granular Structural Fill / Pavements 95 Granular Subbase/ Crushed Base Course 95 Utility Trench Backfill 92 'Subgrade stability must be verified and approved by a representative of the geotechnical engineer prior to any fill placement or construction. 7.7 Utility Trenches Support soils for underground utilities will most likely consist of lean clays, sandy silts and/or silty sands. These soils should provide adequate support for utilities, provided utility subgrades are compacted utilizing vibratory methods, such as with a large vibratory hoe-pack. If utility pipe subgrades are soft, yielding, and/or saturated at the time of construction, subgrade over-excavation and replacement with competent structural fill may be required below utilities. If support soils yield and/or are saturated at the time of construction, we should be notified to observe these soils and provide additional recommendations, as necessary. We strongly recommend backfilling trench excavations with fill soils which meet criteria in section 7.5 Materials, as on-site fine-grained soils (silts and clays) may be difficult to moisture-condition and compact in utility trenches. 7.8 Wet Weather Construction We recommend earthwork for this site be scheduled for the drier seasons of the year. If construction is undertaken in wet periods of the year, it will be important to slope the ground surface to provide drainage away from construction. If construction occurs during or immediately after excessive precipitation, it may be necessary to over- excavate and replace saturated subgrade soil, which might otherwise be suitable. The on-site soils are sensitive to disturbance when wet. If these soils become wet and unstable, we recommend construction traffic is minimized where these soils are exposed. Low ground-pressure (tracked) equipment should be used to minimize disturbance. Soft and disturbed subgrade areas should be excavated to undisturbed soil and backfilled with structural fill. GEOTECHNICAL I ENVIRONMENTAL ALLWESTMATERIALS TESTING I SPECIAL INSPECTION AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 520-448G Wells Avenue Multifamily Development Page 10 Meridian, Idaho In addition, it should be noted the on-site soils tend to have notable adhesion when wet and may be easily transported off-site by construction traffic. 7.9 Cold Weather Construction The on-site soils are frost susceptible. If site grading and construction are anticipated during cold weather, we recommend good winter construction practices be observed. Snow and ice should be removed from excavated and fill areas prior to additional earthwork or construction. Pavement and flatwork portions of the construction should not be placed on frozen ground, nor should the supporting soils be permitted to freeze during or after construction. Frozen soils must not be used as fill. If native subgrades, or suitably moisture-conditioned and compacted fill lifts, will be left exposed to freezing temperatures overnight, those areas should be protected with a minimum of 12 inches of loose soil, or covered with heated construction blankets, so construction subgrades do not freeze. Any frozen soils should be removed prior to additional fill placement or construction of any kind. Earthwork construction during cold inclement weather will require a higher level of attention and detail to achieve required earthwork construction and compaction criteria and may lead to additional earthwork requirements and extended construction schedules. 7.10 Stormwater Disposal During our field exploration we performed seepage testing within test pits TP-1 at 12 feet, TP-4 at 11'/2 feet, and TP-6 at 10 feet, within "dirty" poorly-graded gravel with silt and sand, "clean" poorly-graded gravel with sand, and silt with sand soils, respectively. We obtained field-measured seepage rates of 5 inches per hour(in/hr) in "dirty" gravel, greater than 15 in/hr in "clean" gravel, and 3 in/hr in silt with sand. Due to the variability and strong nature of calcium carbonate cementation (as observed within silty sand soils) and induration (as observed within silt with sand in TP-5), we do not recommend stormwater disposal be planned within or above silt with sand, sandy silt, or silty sand soils, as cemented and indurated soils will exhibit very poor and inconsistent soil seepage. Stormwater disposal facilities must be constructed below the previously mentioned soil types, and into non-cemented gravel-type soils. Refer to individual test pit logs in Appendix B to verify depths and contacts of cemented and indurated soils, as well as contact depths of gravel-type soils. Based on our evaluation and experience with similar soils, the following recommended and allowable seepage rates should be utilized for on-site stormwater disposal. • Silty gravel with sand, poorly-graded gravel with silt and sand ......... 2 in/hr • "Clean" poorly-graded gravel with sand ....................................... 8 in/hr GEOTECHNICAL I ENVIRONMENTAL ALLWESTMATERIALS TESTING I SPECIAL INSPECTION AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 520-448G Wells Avenue Multifamily Development Page 11 Meridian, Idaho Stormwater disposal facilities should be constructed a minimum of 1 foot into the receiving soil. Where "clean" gravels with sand soils were not encountered during our field exploration (due to excavation refusal on cemented soils or due to maximum backhoe equipment reach), we anticipate "clean" gravels with sand will be encountered with depth. "Clean" gravel with sand depths may be determined by utilizing a large track-mounted excavator capable of reaching excavation depths of up to 20 feet. This can be accomplished prior to site construction, to assist civil design, or it can be determined at the time of construction. We remain available to assist with this endeavor, if requested. Seepage beds should be "burrito wrapped" or otherwise maintain a separation/filter fabric between native fine-grained soils and drain rock/filter sand to help prevent fine- soil migration into drainable/filtering media. During construction, ALLWEST should observe stormwater disposal facility subgrades to establish if the suitable receiving soil is encountered, to confirm the allowable seepage rate, and to ensure the separation/filter fabric has been properly installed. The proper separation from bottom of stormwater disposal facilities and seasonal high groundwater should be maintained. At the time of exploration, we did not observe groundwater within test pits to a maximum exploration depth of up to 14 feet below existing ground surfaces. We installed slotted PVC pipes within 4 test pits throughout the site for future groundwater monitoring. At a minimum, these pipes should be monitored during seasonal snow melt and irrigation seasons (March to October), or as required by governing jurisdictions, to confirm the presence or absence of seasonal high groundwater throughout the site. We can provide monthly groundwater monitoring services, at your request. 7.11 Asphalt Pavements Prior to pavement section construction, the pavement subgrade should be proof-rolled as recommended in section 7.2 Site Preparation. Parking and access lanes should be designed for a 20-year Equivalent Single Axle Load (ESAL) of 33,000, which is equivalent to a traffic index (TI) of 6. If actual traffic conditions are different than what is stated, we should be notified so that we may modify our pavement section design. The pavement subgrades consisted of lean clays with sand, or silts with sand. As such, we performed California bearing ratio (CBR) testing on a lean clay with sand soil to assist pavement section design. Based on laboratory testing, we obtained a CBR of 12.7 for the lean clay with sand, which is equivalent to an R-value of 32. We observed lean clay soils that did not contain much sand content; due to that and based our experience with clay-type soils and performance of asphalt pavements, we utilized an R-value of 15 for lean clay for pavement section design. GEOTECHNICAL I ENVIRONMENTAL ALLWESTMATERIALS TESTING I SPECIAL INSPECTION AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 520-448G Wells Avenue Multifamily Development Page 12 Meridian, Idaho The following flexible asphalt pavement section design is provided adhering to the Idaho Transportation Department (ITD), which utilizes the AASHTO pavement design methodology. Based on subgrade preparation requirements, design assumptions, and frost-depth considerations, we recommend the following pavement sections be utilized for subdivision roadway construction for local and collector roadways. Asphalt Crushed Granular Pavement Application Concrete Base Course Subbase inches (inches) (inches) Parking and Access Lanes 2.5 4 11 Base course and subbase should conform to the material recommendations as noted in this report and should be placed over a properly prepared subgrade. The subgrade, subbase, and base course surfaces should slope at no less than 2% away from the crown of the roadway to help reduce the potential for surface water infiltration into the underlying pavement subgrade. Asphalt concrete pavement should be compacted to minimum of 92% of the Rice density. Crack maintenance on pavements should be performed at a minimum of every 3 years, or when cracking is evident. Crack sealing will help reduce surface water infiltration into the supporting soils. 8.0 ADDITIONAL RECOMMENDED SERVICES To maintain continuity and efficiency, we recommend ALLWEST be retained to provide observations and testing throughout construction. As an independent testing company, ALLWEST can document the recommendations included in this report are properly implemented, provide quality control testing, and observe earthwork for conformance to project specifications. As a minimum, we recommend the following testing and observations be provided by ALLWEST: • Observe site stripping, any over-excavations, compaction of test pit backfill, and any other soil backfills. • Observe subgrade proof-rolling and approve subgrades prior to fill construction, materials placement, or pavement section construction. • Observe removal of disturbed soil and subgrade stabilization, if required. • Observe seepage bed subgrades, confirm subsurface seepage rates by performing seepage testing within stormwater disposal facility locations, and observe overall construction. • Conduct compaction testing of fill for general site grading, utilities, and pavement areas. • Observe placement of/test asphalt for compaction, oil content and gradation. GEOTECHNICAL I ENVIRONMENTAL ALLWESTMATERIALS TESTING I SPECIAL INSPECTION AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 520-448G Wells Avenue Multifamily Development Page 13 Meridian, Idaho If we are not retained to provide the recommended construction observation and testing services, we shall not be held responsible for earthwork-related construction errors or omissions. 9.0 EVALUATION LIMITATIONS This report has been prepared to assist planning, design, and construction of the proposed Wells Avenue Multifamily Development in Meridian, Idaho. Our services consist of professional opinions and conclusions made in accordance with generally accepted geotechnical engineering principles and practices in our local area at the time this report was prepared. This acknowledgement is in lieu of all warranties either expressed or implied. Once final structural plans are provided for our review, we can provide foundation- related construction recommendations as an addendum to this report. The following plates complete this report: Appendix A— Site Vicinity Map, Exploration Location Plan Appendix B — Test Pit Logs, Unified Soil Classification System Appendix C — Laboratory Test Results GEOTECHNICAL I ENVIRONMENTAL ALLWESTMATERIALS TESTING I SPECIAL INSPECTION AN EMPLOYEE-OWNED COMPANY Appendix A A-1 — Site Vicinity Map A-2 — Exploration Location Plan ALLWEST Y f • - I + 1 � \ �i. T ws C. 1 Y • 2. �l W LIU 1 m i Figure A-1 - Site Vicinity Map Geotechnical Evaluation Wells - Multifamily Development Meridain, Idaho Linder255 N. Road, Suite 100 -nt: Intermountian Meridian, •. • 83642 ProjectNo.: 1 44: • - 1: :• :•Ti : 1: :•: • • �. - -• 1 ! 4 } r LJ Tp- ■ s. 4 y slp Or r f ■ :gyp o r i Legend 0 Approximate location of test pit observed by ALLWEST. Slotted PVC pipe installed in test pit. Figure A-2 - Exploration Location Plan ALLWEST Geotechnical Evaluation Wells Ave Multifamily Development Meridain, Idaho 255 N. Linder Road, Suite 100 Client: Intermountian Pacific, LLC Meridian, Idaho 83642 Project No.: 520-448G Phone: (208) 895-7898 Fax: (208) 898-3959 Date: February 2021 Appendix B Test Pit Logs Unified Soil Classification System (USCS) ALLWEST ALLWEST DATE STARTED: 1/20/2021 TP - 1 DATE FINISHED: 1/20/2021 EXCAVATOR: CASE 580C MERIDIAN,IDAHO OPERATOR:Steve Just EXCAVATION METHOD:3-ft wide bucket GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc. LOGGER:Anish Pathak TEST PIT LOG WEATHER:Sunny PROJECT:520-448G NOTES:See Figure A-2 in Appendix A for approximate test pit location. Wells Avenue Multifamily Development LATITUDE(DEGREES):N 43°35'17.6388"(43.588233°) = LONGITUDE(DEGREES):W-116°21'52.0704" (-116.364464°) W H U U a o- j TOTAL DEPTH: 13.5' Q 0CL DESCRIPTION W `� NOTES Poorly-graded GRAVEL with silt and sand(Fill);tan, medium dense,moist 00< FILL00< 100< Lean CLAY with sand(Native);brown,stiff, moist 2 CL 3 SILT with sand;brown,medium dense, moist 4 ML 5 Silty SAND;tan to brown,dense,moist T. 6 sM ... moderate cementation observed from 5 to 7 feet 7 Sandy SILT; brown, medium dense, moist 8 BG Passing No.200 sieve=56% ML Moisture content=22% 9 1 Silty GRAVEL with sand;brown,medium dense, moist ° GM 1 ° Poorly-graded GRAVEL with silt and sand; brown, medium dense,moist ° 1 o Field seepage test performed at 12 feet. Field seepage rate=5 in/hr. GP-GM oflc O 1 ° Test pit terminated at 13-1/2 feet. Slotted PVC pipe installed to 13-1/2 feet. 1 WATER LEVELS a WHILE EXCAVATING Y AT COMPLETION 1 AFTER EXCAVATING Sheet 1 of 1 ALLWEST DATE STARTED: 1/20/2021 TP - 2 DATE FINISHED: 1/20/2021 EXCAVATOR: CASE 580C MERIDIAN,IDAHO OPERATOR:Steve Just EXCAVATION METHOD:3-ft wide bucket GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc. LOGGER:Anish Pathak TEST PIT LOG WEATHER:Sunny PROJECT:520-448G NOTES:See Figure A-2 in Appendix A for approximate test pit location. Wells Avenue Multifamily Development LATITUDE(DEGREES):N 43°35'17.664"(43.58824°) = LONGITUDE(DEGREES):W-116°21'48.0492" (-116.363347°) Lu H U U a o- j TOTAL DEPTH: 14' Q 0CL DESCRIPTION W `o NOTES Poorly-graded GRAVEL with silt and sand(Fill);tan, medium FILL dense,moist Lean CLAY with sand(Native);brown,stiff, moist 1 CL 2 SILT with sand;brown,medium dense, moist 3— ML 4 Silty SAND;tan to brown,dense,moist 5 ... moderate cementation observed from 4 to 6 feet 6 SM 7 9 Silty GRAVEL with sand;brown,medium dense, moist ° 1 GM ° 0 1 Poorly-graded GRAVEL with silt and sand; brown, medium dense,moist 0 1 GP-GM 0 O 0 1 Poorly-graded GRAVEL with sand,tan,medium dense, moist GP O Q 14— Test pit terminated at 14 feet. Slotted PVC pipe installed to 14 feet. WATER LEVELS a WHILE EXCAVATING Y AT COMPLETION 1 AFTER EXCAVATING Sheet 1 of 1 ALLWEST DATE STARTED: 1/20/2021 TP - 3 DATE FINISHED: 1/20/2021 EXCAVATOR: CASE 580C MERIDIAN,IDAHO OPERATOR:Steve Just EXCAVATION METHOD:3-ft wide bucket GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc. LOGGER:Anish Pathak TEST PIT LOG WEATHER:Sunny PROJECT:520-448G NOTES:See Figure A-2 in Appendix A for approximate test pit location. Wells Avenue Multifamily Development LATITUDE(DEGREES):N 43°35'15.1368"(43.587538°) = LONGITUDE(DEGREES):W-116°21'52.1244" (-116.364479°) W H U) U a o j TOTAL DEPTH:6' Q 0CL DESCRIPTION W `o NOTES Lean CLAY with sand(Native);brown,stiff, moist CL 1 SILT with sand;brown,medium dense, moist 2- 3— ML 4 Silty SAND;tan to brown,very dense,moist 5 sM .strong to very strong cementation observed from 4-1/2 to 6 feet 6 Test pit terminated at 6 feet due to refusal on strong cementation. 7 8 9 1 1 1 1 1 WATER LEVELS a WHILE EXCAVATING Y AT COMPLETION 1 AFTER EXCAVATING Sheet 1 of 1 ALLWEST DATE STARTED: 1/20/2021 TP - 4 DATE FINISHED: 1/20/2021 EXCAVATOR: CASE 580C MERIDIAN,IDAHO OPERATOR:Steve Just EXCAVATION METHOD:3-ft wide bucket GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc. LOGGER:Anish Pathak TEST PIT LOG WEATHER:Sunny PROJECT:520-448G NOTES:See Figure A-2 in Appendix A for approximate test pit location. Wells Avenue Multifamily Development LATITUDE(DEGREES):N 43°35'14.8668"(43.587463°) = LONGITUDE(DEGREES):W-116°21'47.4336" (-116.363176°) W H U U a o j TOTAL DEPTH: 12.5' CL Q 0 DESCRIPTION W `� NOTES Lean CLAY with sand(Native);brown,stiff, moist 1 Passing No.200 sieve=80% cL BK LL=42, PL=24,PI= 18 CBR=12.7 2 3 Sandy SILT; brown, medium dense, moist BG Passing No.200 sieve=54% Moisture content=31% 4 ML 5 Silty SAND;tan to brown,dense,moist 6 ... moderate cementation observed from 5 to 7 feet 7 BG Passing No.200 sieve=44% sM Moisture content=20% 8 9 1 Poorly-graded GRAVEL with silt and sand; brown, medium dense,moist GP-GM G 1 0 0 Poorly-graded GRAVEL with sand;tan,medium dense, moist Field seepage test performed at 11-1/2 feet. 0 Field seepage rate=>15 in/hr. 1 GP p Q Test pit terminated at 12-1/2 feet. Slotted PVC pipe installed to 12-1/2 feet. 1 1 WATER LEVELS a WHILE EXCAVATING Y AT COMPLETION 1 AFTER EXCAVATING Sheet 1 of 1 ALLWEST DATE STARTED: 1/20/2021 TP - 5 DATE FINISHED: 1/20/2021 EXCAVATOR: CASE 580C MERIDIAN,IDAHO OPERATOR:Steve Just EXCAVATION METHOD:3-ft wide bucket GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc. LOGGER:Anish Pathak TEST PIT LOG WEATHER:Sunny PROJECT:520-448G NOTES:See Figure A-2 in Appendix A for approximate test pit location. Wells Avenue Multifamily Development LATITUDE(DEGREES):N 43°35'12.5952"(43.586832°) (0 = LONGITUDE(DEGREES):W-116°21'52.1064" (-116.364474°) Lu H U) U a o j TOTAL DEPTH: 13' Q 0CL DESCRIPTION W `o NOTES Lean CLAY with sand(Native);brown,stiff, moist 1 cL 2 SILT with sand;brown,medium dense, moist 3 ML 4 Silty SAND;tan to brown,dense,moist 5 6 ...weak to moderate cementation observed from 4-1/2 to 8 feet SM 7 9 SILT with sand;brown,medium dense, moist 1 1 ML ... induration observed from 9 to 13 feet BG 1 13-- Test pit terminated at 13 feet. 1 WATER LEVELS a WHILE EXCAVATING Y AT COMPLETION 1 AFTER EXCAVATING Sheet 1 of 1 ALLWEST DATE STARTED: 1/20/2021 TP - 6 DATE FINISHED: 1/20/2021 EXCAVATOR: CASE 580C MERIDIAN,IDAHO OPERATOR:Steve Just EXCAVATION METHOD:3-ft wide bucket GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc. LOGGER:Anish Pathak TEST PIT LOG WEATHER:Sunny PROJECT:520-448G NOTES:See Figure A-2 in Appendix A for approximate test pit location. Wells Avenue Multifamily Development LATITUDE(DEGREES):N 43°35'12.4764"(43.586799°) (0 = LONGITUDE(DEGREES):W-116°21'46.8792" (-116.363022°) Lu H U) U a o j TOTAL DEPTH: 12' Q 0CL DESCRIPTION W `o NOTES Lean CLAY with sand(Native);brown,stiff, moist 1 cL 2 Sandy SILT; brown, medium dense, moist 3 ML 4 Silty SAND;tan to brown,dense,moist 5 ... moderate cementation observed from 4 to 7 feet 6 SM 7 g SILT with sand;brown,medium dense, moist BG Passing No.200 sieve=72% Moisture content=25% 1 Field seepage test performed at 10 feet. ML Field seepage rate=3 in/hr. 1 1 Test pit terminated at 12 feet. 1 1 —75 WATER LEVELS a WHILE EXCAVATING Y AT COMPLETION 1 AFTER EXCAVATING Sheet 1 of 1 ALLWEST DATE STARTED: 1/20/2021 TP - 7 DATE FINISHED: 1/20/2021 EXCAVATOR: CASE 580C MERIDIAN,IDAHO OPERATOR:Steve Just EXCAVATION METHOD:3-ft wide bucket GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc. LOGGER:Anish Pathak TEST PIT LOG WEATHER:Sunny PROJECT:520-448G NOTES:See Figure A-2 in Appendix A for approximate test pit location. Wells Avenue Multifamily Development LATITUDE(DEGREES):N 43°35'10.1076"(43.586141°) (0 = LONGITUDE(DEGREES):W-116°21'52.1244" (-116.364479°) W H U) U a 0- j TOTAL DEPTH:8' Q 0CL DESCRIPTION W `o NOTES Lean CLAY(Native); brown,stiff, moist 1 cL Passing No.200 sieve=88% BG Moisture content=23% ILL=34, PL=21,PI= 13 2 SILT with sand;brown,medium dense, moist BG Passing No.200 sieve=83% Moisture content=20% 3 ML 4 5 Silty SAND;tan to brown,dense to very dense,moist 6 sM ... moderate to very strong cementation observed from 5 to 8 feet BG Passing No.200 sieve=23% Moisture content=28% 7 8 Test pit terminated at 8 feet due to refusal on strong cementation. 9 1 1 1 1 1 WATER LEVELS a WHILE EXCAVATING Y AT COMPLETION 1 AFTER EXCAVATING Sheet 1 of 1 ALLWEST DATE STARTED: 1/20/2021 TP - 8 DATE FINISHED: 1/20/2021 EXCAVATOR: CASE 580C MERIDIAN,IDAHO OPERATOR:Steve Just EXCAVATION METHOD:3-ft wide bucket GEOTECHNICAL SECTION COMPANY:Just Dig'It Exc. LOGGER:Anish Pathak TEST PIT LOG WEATHER:Sunny PROJECT:520-448G NOTES:See Figure A-2 in Appendix A for approximate test pit location. Wells Avenue Multifamily Development LATITUDE(DEGREES):N 43°35'10.2156"(43.586171°) (0 = LONGITUDE(DEGREES):W-116°21'46.8432" (-116.363012°) Lu H U) U a o j TOTAL DEPTH: 14' Q 0CL DESCRIPTION W `o NOTES Lean CLAY(Native); brown,stiff, moist 1 cL 2 Sandy SILT; brown, medium dense, moist 3 ML 4 Silty SAND;tan to brown,dense to very dense,moist 5 ...weak to moderate cementation observed from 5 to 6-1/2 feet 6 7 SM ...strong cementation observed from 6-1/2 to 9 feet 8 9 1 SILT with sand;brown,medium dense, moist BG 1 ML 1 Silty GRAVEL with sand;brown,medium dense, moist 0 1 GM 0 14— Test pit terminated at 14 feet. Slotted PVC pipe installed to 14 feet. WATER LEVELS a WHILE EXCAVATING Y AT COMPLETION 1 AFTER EXCAVATING Sheet 1 of 1 Unified Soil Classification System MAJOR DIVISIONS SYMBOL TYPICAL NAMES Well-Graded Gravel, CLEAN GW Gravel-Sand Mixtures. GRAVELS GP Poorly-Graded Gravel, GRAVELS Gravel-Sand Mixtures. Silty Gravel, COARSE GRAVELS GM Gravel-Sand-Silt Mixtures. GRAINED WITH FINES GC Clayey Gravel, SOILS Gravel-Sand-Clay Mixtures. Well-Graded Sand, CLEAN SW Gravelly Sand. SANDS SP Poorly-Graded Sand, SANDS Gravelly Sand. Silty Sand, SANDS L SM Sand-Silt Mixtures. WITH FINES Sc Clayey Sand, Sand-Clay Mixtures. ML Inorganic Silt, SILTS AND CLAYS Silty or Clayey Fine Sand. Inorganic Clay of Low to LIQUID LIMIT CL Medium Plasticity, LESS THAN 50% Sandy or Silty Clay. FINE OL Organic Silt and Clay of Low GRAINED Plasticity. SOILS Inorganic Silt, Elastic Silt, SILTS AND CLAYS MH Micaceous Silt, Fine Sand or Silt. LIQUID LIMIT CH Inorganic Clay of High Plasticity, GREATER THAN 50% Fat Clay. OH Organic Clay of Medium to High Plasticity. Highly Organic Soils PT Peat, Muck and Other Highly Organic Soils. ALLWEST Appendix C Laboratory Test Results ALLWEST Summary of Laboratory Test Results Moisture Gradation Atterberg Limits Test Pit Depth Content Liquid Plasticity CBR Sample Classification No. (Feet) (%) Gravel Sand Silt/Clay Limit Index (USCS) N N N M) N TP-1 8 - 8.5 22 44 56 Sandy SILT (ML) TP-4 1 - 2 20 80 42 18 12.7 Lean CLAY with sand (CL) TP-4 3 - 3.5 31 46 54 Sandy SILT (ML) TP-4 7 - 7.5 20 56 44 Silty SAND (SM) TP-6 9.5 - 10 25 28 72 SILT with sand (ML) TP-7 1 - 1.5 23 12 88 34 13 Lean CLAY(CL) TP-7 2.5 - 3 20 17 83 SILT with sand (ML) TP-7 6.5- 7 28 77 23 Silty SAND (SM) Table C-1 255 N. Linder Road, Suite 100 • Meridian, Idaho 83642 • (208) 895-7895 • Fax (208) 898-3959 www.allwesttesting.com This report may not be reproduced, except in full, without the permission of ALLWEST. LIQUID AND PLASTIC LIMITS TEST REPORT 60 Dashed line indicates the approximate upper limit boundary for natural soils 50 O �0 ' G 40 U C � X W N— Z_ � v 30 c F- LU C/) ' Q i J / a: 20 H U) LU J / ■ J Q 10 0 ; c L-MIL ML or OL MH or OH 0 0 10 20 30 40 50 60 70 80 90 100 110 LIQUID LIMIT 0 MATERIAL DESCRIPTION LL PL PI %<#40 %<#200 USCS • Lean Clay with sand 42 24 18 80% CL c■ Lean Clay 34 21 13 88% CL CD U X U U U 7 O ` Project No. 520-448G Client: Intermountain Pacific,LLC Remarks: aD Project: Wells Avenue Multifamily Development c *Location: TP-4 Depth: F-2' ■Location: TP-7 Depth: F-1.5' 0 cn ALLWEST E Figure C-1 Tested By: C. Downes Checked By:J.Varozza California Bearing Ratio ASTM D 1883 Project: Wells Avenue Multifamily Development Project No.: 520-448G Client: Intermountain Pacific, LLC Location: TP-4 @ 1 - 2 ft Date Tested: 2/8/2021 Compaction Method: ASTM D1557 Tested By: C. Downes Classification: Lean Clay with sand (CL) 275 250 225 200 a 175 c 150 'a c 125 VI L PSI @ 0.1 inch penetration= 127 N 100 75 50 25 0 0 0.1 0.2 0.3 0.4 0.5 Penetration(inches) CBR @ 0.1 Inch Penetration: 12.7 Maximum Dry Unit Weight (pcf): 106.3 Swell (%): 2.4 Optimum Water Content (%): 17.4 Dry Unit Weight Before Soak(pcf): 95.8 Remold of Max. Dry Unt Wgt(%): 90 Water Content Before Soak (%): 19.3 Water Content After Soak, Top 1 Inch (%): 33.6 Surcharge (psf): 50 Immersion Period (hrs): 96 Reviewed By: James Varozza Figure: C-2 ►LL1 EST 255 N Linder Rd,Suite 100•Meridian,ID 83642•(208)895-7898•Fax(208)898-3959 www.allwesttesting.com This report shall not be reproduced except in full without the permission of ALLW EST.