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HomeMy WebLinkAboutPZ - Geotech NMENTAL TECHNICAL ALLWEST MATERIALS OTESTING I SPEC AL IRO PECT ON AN EMPLOYEE-OWNED COMPANY April 4, 2025 BLM Venture, LLC P.O. Box 190804 Bosie, Idaho 83719 Attention: Lynn Carrillo (lynn ccD-ethridgedevelopment.com) RE: Geotechnical Evaluation Farrington Heights Subdivision 1130 East Pine Avenue Meridian, Idaho ALLWEST Project No. 524-69OG Lynn Carrillo, ALLWEST has completed the authorized geotechnical evaluation for the proposed Farrington Heights Subdivision to be located at 1130 East Pine Avenue in Meridian, Idaho. The purpose of this evaluation was to characterize the subsurface conditions at the project site and prepare the attached report with the results of the field evaluation and our geotechnical recommendations to assist with design and construction of the proposed development. We appreciate the opportunity to work with you on this project. Please contact us if you have any questions or need additional information. Sincerely, ALLWEST Kevin Dyekman, P.G. Scott M. Fraser, P.E. Area Manager/ Engineering Geologist Engineering Services Manager 255 N. Linder Road, Meridian, ID 83642 Phone: 208.895.7898 Hayden, ID• Lewiston, ID •Meridian, ID •Missoula, MT•Spokane Valley, WA•Tri-Cities,WA www.allwesttesting.com GEOTECHNICAL EVALUATION FARRINGTON HEIGHTS SUBDIVISION 1130 EAST PINE AVENUE MERIDIAN, IDAHO PROJECT NO. 524-69OG April 4, 2025 >r r �11 Prepared for: BLM VENTURE, LLC P.O. BOX 190804 ,stiONAL CENSE� BOSIE, IDAHO 83719 66 Prepared by: ALLWEST n0T9TE OF 1���0 4'� 255 N. LINDER ROAD 5 P M FgA -r/4/2025 MERIDIAN, IDAHO GEOTECHNICAL EVALUATION FARRINGTON HEIGHTS SUBDIVISION 1130 EAST PINE AVENUE MERIDIAN, IDAHO 1.0 EXECUTIVE SUMMARY ALLWEST has completed the authorized geotechnical evaluation for the proposed Farrington Heights Subdivision project located at 1130 East Pine Avenue in Meridian, Idaho. Our services were provided in accordance with our proposal dated February 10, 2025. The site is suitable for the proposed development provided the recommendations in this report are properly implemented during design and construction. Close monitoring of the construction operations discussed herein will be critical in achieving the design subgrade support and is required by the International Building Code (IBC). If we are not retained to provide required construction observation and materials testing services, we cannot be responsible for soil engineering related construction errors or omissions. The following summarizes select geotechnical information/recommendations from this evaluation: ♦ In general, natural soil consisted of lean clays with varying amounts of sand, fat clays with sand, sands with silt, and gravels with sand. ♦ Varying thicknesses of weak to strong cementation were commonly observed within the silty sand soil layers. ♦ At the time of exploration, we did not observe groundwater within the test pits to the maximum exploration depth of 10'/2 feet below existing ground. ♦ We anticipate approximately 3 inches of site stripping will be required for most of the site to remove topsoil containing significant roots and organics. ♦ Stormwater disposal is feasible within the poorly graded gravel with sand, as observed during our field exploration. A design infiltration rate of 8 inches per hour (in/hr) may be utilized for stormwater disposal into poorly graded gravel with sand. ♦ For local roadways we recommend pavement sections of 2.5-inches of asphalt concrete, over 4-inches of crushed aggregate base, over 9-inches of aggregate subbase. ♦ For collector roadways we recommend pavement sections of 3-inches of asphalt concrete, over 6-inches of crushed aggregate base, over 11-inches of aggregate subbase. This summary should be used in conjunction with the entire report. It should be recognized that details were not included or fully developed in this section, and the report must be read in its entirety for a comprehensive understanding of the items contained herein. GEOTECHNICAL I ENVIRONMENTAL MATERIALS TESTING I SPECIAL INSPECTION ALLWEST AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 524-69OG Farrington Heights Subdivision April 4, 2025 Meridian, Idaho Page 2 2.0 PROJECT DOCUMENTS The following documents were provided to ALLWEST to help our understanding of the planned development: ♦ Cover Sheet and General Information, Pine-Adkins Subdivision, Ethridge Development, by Studio H Architects, dated August 20, 2024. ♦ Farrington Heights Subdivision, 1100, 1120, 1180 E Pine Avenue, Meridian ID 83642, prepared by Studio H Architects, dated February 10, 2025. 3.0 PROJECT DESCRIPTION Based on communication with you and review of the project documents, we understand that development will consist of a 4.68-acre residential subdivision with associated infrastructure, stormwater disposal facilities, and asphalt-paved roadways. The subdivision will include 37 lots for single-family residences. Grading plans were not provided for our review; however,we assume cuts and fills for general site grading to be two feet or less. 4.0 SITE CONDITIONS At the time of exploration, the site was comprised of pastureland in the northern portion of the property with residences and a livestock corral located in the southern portion of the property. The site is bordered by Adkins Lane to the east, West Pine Avenue to the south, and the Danbury Fair Subdivision to the north and west. The general location of the project site is shown on Figure A-1: Vicinity Map in Appendix A. 4.1 Published Subsurface Conditions The geologic conditions at the site are mapped as Gravel of Whiteny Terrace (map symbol — Qwg) on the "Geologic Map of the Boise Valley and Adjoining Area, Western Snake River Plain, Idaho", by K.L. Othberg, and L.R. Stanford, 1992. This geologic unit is described as sandy pebble and cobble gravel that is 16 to 80 feet thick and is mantled by 2 to 7 feet of loess. The USDA Natural Resources Conservation Service (NRCS) has mapped near surface soil types on the project site as Aquic Torriorthents and Purdam silt loam. These soil units consist of loam, silt loam, silty clay loam, stratified sand to loam, sand, gravel, and cemented material. The Aquic Torriorthents is described as somewhat poorly drained soil formed from mixed alluvium. The capacity of the most limiting layer to transmit water is moderately high to high. The Purdam silt loam is described as well drained soil formed from mixed alluvium, lacustrine deposits, and/or loess. The capacity of the most limiting layer to transmit water is very low to moderately low. 4.2 Subsurface Exploration Program We observed the excavation of six test pits (TP-1 through TP-6) at the site on March 6, 2025, utilizing a Case 580C backhoe with a 24-inch toothed excavation bucket. Test pits were advanced to maximum depths of 9 to 10.5 feet below the existing ground surface. Maximum depths varied GEOTECHNICAL I ENVIRONMENTAL MATERIALS TESTING I SPECIAL INSPECTION ALLWEST AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 524-69OG Farrington Heights Subdivision April 4, 2025 Meridian, Idaho Page 3 due to caving conditions encountered within the test pits. The soil conditions observed in the test pits were described and classified in general accordance with ASTM D2488. We obtained representative soil samples from the test pit side walls or excavation spoil piles for further identification and laboratory testing. The approximate locations of the test pits are shown on Figure A-2: Site and Exploration Map in Appendix A. Field infiltration testing was performed within select test pits to assess the rate at which water permeates into the subsurface soil. Infiltration testing was performed using general open pit-falling head methodology. 4.3 Soil Characterization Detailed descriptions of the observed soil are presented on the exploration logs in Appendix B. The descriptive soil terms used on the exploration logs, and in this report, can be referenced on the Unified Soil Classification System (USCS) included as part of the Soil Classification Chart in Appendix B. The subsurface conditions may vary between exploration locations; such changes in subsurface conditions may not be apparent until construction. General descriptions of the observed soil units follow: Topsoil: Topsoil containing abundant roots and organics was observed in each test pit. The topsoil layer was observed to be approximately 3 inches thick. Natural Soil: Natural soil consisted of lean clays with varying amounts of sand, fat clays with sand, sands with silt, and gravels with sand. Gravel with sand soil units included subrounded gravel and cobble clasts up to 10 inches in maximum dimension. Varying thicknesses of weak to strong cementation were commonly observed within the silty sand soil layers. Fat Clay: Fat clay soil was observed in test pit TP-6 to a depth of 1.5 feet below existing ground surface. Fat clay is considered expansive soil that is subject to significant volumetric change (shrink and swell)with fluctuations in moisture content. These volumetric changes can negatively affect buildings, roads, pipelines, and other improvements, if not properly mitigated. 4.4 Groundwater Conditions We did not observe groundwater within the test pits to the maximum exploration depth of 10'/2 feet below existing ground. Groundwater in the area may be influenced by local irrigation and nearby canals, ditches, and laterals. Changes in precipitation, construction, and other factors may also impact the depth to groundwater on-site. As a result, actual groundwater conditions may be different during development. Groundwater will fluctuate throughout the year and will likely peak during snowmelt and irrigation seasons (typically March to October). We installed slotted pipes within some of the test pits for future groundwater monitoring. If requested, ALLWEST can perform monthly groundwater monitoring to help establish seasonal high groundwater on-site. GEOTECHNICAL I ENVIRONMENTAL MATERIALS TESTING I SPECIAL INSPECTION ALLWEST AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 524-69OG Farrington Heights Subdivision April 4, 2025 Meridian, Idaho Page 4 5.0 LABORATORY TESTING We performed laboratory testing to supplement field classifications and to assess some of the soil engineering properties. The laboratory testing completed, and the information acquired, are presented in Table 1. The laboratory test results are included in Appendix C and select results are also presented on the exploration logs in Appendix B. Table 1 - Laboratory Tests Test Performed Information Acquired Natural Water Content Water content representative of soil conditions at the time (ASTM D2216) and location samples were collected. Fines Content Portion of soil passing the No. 200 sieve (silt/clay). (ASTM D1140) Atterberg Limits Effects of varying water content on the consistency of fine- (ASTM D4318) grained soil present in a particular sample. California Bearing Ratio This test method is used to evaluate the strength and load- (ASTM D1883) bearing capacity of subgrade soil and/or materials for pavement design and construction. 6.0 CONCLUSIONS AND RECOMMENDATIONS Based on our understanding of the project and the subsurface conditions presented in the previous sections of this report, the site is suitable for the proposed development provided the recommendations presented herein are properly implemented during design and construction. If the proposed construction changes or if unforeseen conditions are encountered, we must be given the opportunity to review the current information and update our recommendations. Additionally, we should be given the opportunity to review development plans and specifications to confirm the recommendations presented in this report were properly incorporated. 6.1 Site Preparation Clearing and Stripping: Topsoil containing abundant roots and organics should be removed (i.e., stripped) below proposed development areas. Based on the subsurface conditions observed in our explorations, we anticipate approximately 3 inches of stripping will be required for most of the site. Stripped materials should be disposed of off-site or only used for topsoil within non-structural landscape areas. Where trees will be removed (i.e., cleared) as part of the development, large root systems should be completely over-excavated to suitable natural soil. Demolition: We anticipate existing improvements (structures, utilities, infrastructure, etc.) will be demolished and removed as part of development. Existing improvements should be completely removed and over-excavated to suitable natural soil. This also includes basements, septic tanks, and wastewater drainfields. GEOTECHNICAL I ENVIRONMENTAL MATERIALS TESTING I SPECIAL INSPECTION ALLWEST AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 524-69OG Farrington Heights Subdivision April 4, 2025 Meridian, Idaho Page 5 Unsuitable Soil: Unsuitable soil is present on-site and is not acceptable to support site grading fill, pavement sections, structural improvements, or any other type of development. This soil should be completely over-excavated to suitable natural soil within proposed development areas. The following soil types are unsuitable: ♦ Fat clay soil has a high potential to swell and shrink with variations in moisture content and may impact aspects of proposed development. Fat clay soil was observed in test pit TP-6 to a depth of 1.5 feet below existing ground surface. Test Pit Remediation: Test pit excavations were loosely backfilled with the excavated soil following logging. To reduce the potential for future settlement, we recommend that test pit backfill be entirely over-excavated below development areas. The approximate test pit locations are shown on Figure A-2: Site and Exploration Map in Appendix A and their depths are presented on the exploration logs in Appendix B. Over-Excavations: Depths and lateral limits of over-excavations may not fully be known until earthwork begins. Over-excavations associated with tree removal, demolition, unsuitable soil, and test pit remediation should be backfilled with suitably moisture-conditioned and compacted site grading fill in accordance with the following sections of this report. Subgrade Preparation: Subgrade refers to the natural soil exposed at the base of any excavation. Subgrades should be evaluated by the geotechnical engineer of record, or staff under their supervision, to determine that they are suitable and that the actual subsurface conditions are consistent with those observed during exploration. Exposed subgrades should be evaluated by proof-rolling using vibratory rollers, loaded dump trucks/front-end loaders, vibratory hoe-packs, or other suitable equipment. If natural subgrades are observed to significantly deflect or pump during proof-rolling, the subgrades are not suitable, and subgrade stabilization will be needed.ALLWEST should be consulted to provide recommendations to achieve a stable subgrade based on the actual conditions observed during earthwork. 6.2 Temporary Excavation and Trenching Based on the conditions observed within our explorations, we anticipate excavation of the on-site soil can be achieved with typical excavation equipment. Temporary excavation slope stability is a function of many factors, including the presence and abundance of groundwater, the type and density of the various soil strata, the depth of cut, the presence of surcharge loads adjacent to the excavation, and the length of time the excavation remains open. It is exceedingly difficult under the variable circumstances to pre-establish a safe and "maintenance-free" temporary cut slope angle. Therefore, it is the responsibility of the contractor to maintain safe temporary slope configurations since the contractor is continuously at the job site, able to observe the nature and condition of the cut slopes, and able to monitor the subsurface materials and groundwater conditions encountered. Unsupported vertical slopes or cuts deeper than 4 feet are not recommended if worker access is necessary. The cuts should be adequately sloped, shored, or supported to prevent injury to personnel from local sloughing and spalling. The excavation should conform to applicable federal, state, and local regulations. Regarding trench GEOTECHNICAL I ENVIRONMENTAL MATERIALS TESTING I SPECIAL INSPECTION ALLWEST AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 524-69OG Farrington Heights Subdivision April 4, 2025 Meridian, Idaho Page 6 wall support, the site soil is considered Type C soil according to OSHA guidelines and therefore should not exceed a 1.5H:1 V (horizontal to vertical) temporary slope. 6.3 Materials Stripped soil containing abundant roots and organics should be disposed of off-site or only used for topsoil within non-structural landscape areas. Fat clay-type soil is not suitable to be used as fill and should be disposed of off-site. Site grading fill for general earthwork should have a liquid limit less than 50 and not contain materials greater than 6 inches in maximum dimension. Based on our observations and testing, natural lean clay with sand, sandy lean clay, silty sand, and poorly graded gravel with sand may be used as general site grading fill. Imported materials should consist of granular soil that is, free of organics, debris, and other deleterious material and meet the following criteria. Imported materials should be approved by the geotechnical engineer prior to delivery to the site. Recommended criteria for imported soil and aggregate types are presented in Table 2. Table 2 - Imported Soil and Aggregate Recommendations. Type Criteria Maximum size <_ 6 inches, Granular Structural Fill / Retained on 3/4-inch sieve < 30%, Subbase Passing No. 200 Sieve <_ 15%, and non-plastic. Alternatively, meet ISPWC section 801 (6-inch maximum) or 802 (Type 11). Maximum size <_ 1 inch, Crushed Aggregate Base Retained on 3/4-inch sieve <010%, Passing No. 200 sieve < 10/o, and Non-plastic. Alternatively, meet ISPWC section 802 (Type 1) Maximum size <_ 3 inches; Utility Trench Backfill Retained on 3/4-inch sieve < 30%; (above pipe bedding) Passing No. 200 sieve <_ 10%; Non-plastic Or meet ISPWC section 801 (3-inch maximum) 6.4 Fill Placement and Compaction Prior to fill placement, exposed subgrades should be observed and approved by the geotechnical engineer of record, or their representative. Fill should be placed in lift thicknesses which are appropriate for the compaction equipment used. Typically, 8-to 12-inch-thick lifts are appropriate for typical rubber-tire and steel-drum compaction equipment. Lift thickness should be reduced to 4 inches for hand operated compaction equipment. Fill should be moisture conditioned to within 2 percentage points of the optimum moisture content prior to placement to facilitate compaction. Fill should be compacted to the minimum relative compaction of the maximum dry density, as determined by ASTM D1557 (modified Proctor), provided in Table 3. GEOTECHNICAL I ENVIRONMENTAL MATERIALS TESTING I SPECIAL INSPECTION ALLWEST AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 524-69OG Farrington Heights Subdivision April 4, 2025 Meridian, Idaho Page 7 Table 3 - Compaction Requirements Minimum Relative Type Compaction Site Grading Fill 95 Structural Fill /Subbase 95 Crushed Aggregate Base 95 Utility Trench Backfill 92 For roadway and utility construction, local governing agencies may supersede the criteria presented herein, and may provide their own minimum compaction requirements and methods of determining maximum density. This also includes preparation and approval requirements for exposed subgrades. For materials that are too granular to test (generally greater than 30 percent retained on a 3/4-inch sieve), an appropriate method-based compaction specification should be used in accordance with local governing jurisdictions or as outlined in Section 202.3.8.C.3 of the Idaho Standards for Public Works Construction (ISPWC). Fine-grained soil (silts and clays) may be difficult to moisture-condition and compact in utility trenches. Therefore, we recommend backfilling trench excavations with soil that meet the criteria presented in Table 2. 6.5 Wet Weather Construction Due to wet weather conditions in this climatic region during late fall, winter, and early spring, we recommend construction (especially site grading)take place during the late spring, summer, and early fall seasons, if possible. If construction occurs during or immediately after excessive precipitation or snowmelt, it may be necessary to over-excavate and replace wet subgrade soil which might otherwise be suitable. 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. In addition, wet soil tends to have notable adhesion and may be easily transported off-site by construction traffic. 6.6 Cold Weather Construction 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 all fill placement surfaces prior to additional earthwork or construction. Improvements should not be placed on frozen ground, nor should the supporting soil be permitted to freeze during or after construction. Frozen soil should not be used as fill. Construction subgrades left exposed to freezing temperatures overnight can be protected with a temporary lift of loose soil or covered with heated construction blankets, so subgrades do not freeze. Frozen cover soil should be removed prior to any fill placement or construction. GEOTECHNICAL I ENVIRONMENTAL MATERIALS TESTING I SPECIAL INSPECTION ALLWEST AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 524-69OG Farrington Heights Subdivision April 4, 2025 Meridian, Idaho Page 8 6.7 Stormwater and Drainage We recommend ground surfaces be sloped to direct water runoff away from structural foundations and pavement areas. We recommend the ground surface be sloped a minimum of 5% within 10 feet of foundations. In cases where the recommended grade cannot be achieved due to site constraints, drains should be installed to effectively divert water away from foundations. Impervious surfaces, like concrete or pavers, should slope a minimum of 2% within 10 feet of foundations. Ultimately, water should not be allowed to infiltrate or pond adjacent to foundations and pavement areas. 6.8 Infiltration Recommendations We anticipate surface water runoff will be directed to stormwater disposal facilities (detention basins, seepage beds, etc.) for the overall development. Final locations of planned stormwater disposal facilities were not known at the time of this report. The infiltration recommendations provided below are for specific soil types and subsurface conditions observed during our exploration. During exploration, we performed infiltration testing in test pits TP-1, -3, and -4 within on-site poorly graded gravel with sand soil. Varying levels of cementation were commonly observed during exploration within the silty sand soil layers. We do not recommend stormwater disposal be accomplished within cemented soil, as they typically exhibit very poor and inconsistent infiltration. Refer to the test pit logs in Appendix B to verify depths and contacts of soil which is not suitable for stormwater disposal. Stormwater disposal is feasible within the poorly graded gravel with sand soil, as observed during our field exploration. Based on infiltration test results and our experience with similar soil types, the design infiltration rates provided in Table 4 may be utilized for on-site stormwater disposal design. Table 4 - Infiltration Rates Field-Measured Design Infiltration Soil Type Infiltration Rate in/hr Rate in/hr Poorly graded gravel with >15 8 sand Additional infiltration testing may be needed once stormwater disposal facility locations are determined and should be performed using methodology accepted by the governing jurisdiction. Stormwater disposal facilities should be constructed a minimum of 1 foot into the recommended receiving soil. Filter fabric should be properly utilized to separate natural soil from stormwater disposal facility drain rock and filter sand materials to help reduce the migration of fine soil into drain rock and filter sand void space. The proper separation from bottom of stormwater disposal facilities and seasonal high groundwater should be maintained in accordance with the governing jurisdiction. Groundwater monitoring should be performed throughout seasonal snowmelt and irrigation seasons (typically March to October) to help establish a seasonal high groundwater GEOTECHNICAL I ENVIRONMENTAL MATERIALS TESTING I SPECIAL INSPECTION ALLWEST AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 524-69OG Farrington Heights Subdivision April 4, 2025 Meridian, Idaho Page 9 elevation at the site. If requested, ALLWEST can perform monthly groundwater monitoring for the site. 6.9 Pavement Based on our exploration and understanding of the proposed development, we anticipate that pavement subgrade areas will consist of lean clays with sand, sandy lean clays, and/or silty sands. We performed CBR testing on a sandy lean clay soil sample and obtained a value of 17.0 percent. Prior to pavement section construction, subgrades should be proof-rolled as recommended in section 6.1 Site Preparation or prepared as required by local jurisdictions. Anticipated traffic conditions were not provided for our pavement design. The parameters used in our pavement section design were estimated based on our experience with similar projects. If actual traffic conditions vary from those stated in Table 5, we should be notified so we may redesign the recommended pavement sections. Table 5 - Pavement Design Parameters Design Parameter Value California Bearing Ratio (CBR) 17.0% Equivalent Single- Local Roadways 33,0001 Axle Loads (ESALs) Collector Roadways 370'0002 Pavement Reliability 90% Pavement Design Life 20- ear Initial Serviceability 4.2 Terminal Serviceability 2.5 Approximately equivalent to a Traffic Index of 6. 2Approximately equivalent to a Traffic Index of 8. The following sections were designed utilizing ITD gravel equivalent methodology and, our experience with local jurisdictions. Recommended flexible pavement sections are presented in Table 6. Table 6 - Recommended Pavement Sections Flexible Pavement Crushed Base Pavement Area Asphalt in. Course in. Subbase in. Local Roads 2.5 4 9 Collector Roads 3 6 11 Pavements should be sloped to provide suitable drainage of surface water. Water allowed to pond on or adjacent to the pavements could saturate the subgrade and contribute to premature GEOTECHNICAL I ENVIRONMENTAL MATERIALS TESTING I SPECIAL INSPECTION ALLWEST AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 524-69OG Farrington Heights Subdivision April 4, 2025 Meridian, Idaho Page 10 pavement deterioration. In addition, the pavement subgrade should be graded to provide positive drainage within the crushed base course/subbase subsections. The pavement sections provided in this report represent minimum recommended thicknesses. Preventive maintenance (crack/joint sealing, patching, overlay, etc.) should be planned as part of an on-going pavement management program. Preventive maintenance is intended to slow the rate of pavement deterioration and preserve the integrity of the pavement. 7.0 ADDITIONAL RECOMMENDED SERVICES ALLWEST should review final development plans and specifications to confirm the recommendations presented in this report were properly incorporated. Close monitoring of the construction operations discussed herein will be critical in achieving the design subgrade support and is required by the International Building Code. We recommend ALLWEST be retained to provide observation and testing services throughout construction. We recommend the following testing and observations be provided by ALLWEST: ♦ Observe site stripping, test pit remediation, and any other soil over-excavations and backfills. ♦ Observe subgrade proof-rolling and approve subgrades prior to fill/materials placement or roadway section/utility construction. ♦ Observe stormwater disposal facility subgrade soil and overall stormwater disposal facility construction. ♦ Conduct compaction testing of any fill soil placed for general site grading, utility backfills, and pavements. ♦ Observe placement of/test asphalt for compaction, oil content, and gradation. If we are not retained to provide the recommended construction observation and materials testing services, we cannot be responsible for errors and omissions related to geotechnical aspects of the project construction. 8.0 EVALUATION LIMITATIONS This report has been prepared to assist the design and construction for the propsed Farrington Heights Subdivision project located at 1130 East Pine Avenue in Meridian, Idaho. Reliance by any other party is prohibited without the written authorization of ALLWEST. Our services consist of professional opinions and conclusions made in accordance with generally accepted geotechnical engineering principles and practices in the local area at the time this report was prepared. This acknowledgement is in lieu of all warranties, express or implied. GEOTECHNICAL I ENVIRONMENTAL MATERIALS TESTING I SPECIAL INSPECTION ALLWEST AN EMPLOYEE-OWNED COMPANY Geotechnical Evaluation ALLWEST Project No. 524-69OG Farrington Heights Subdivision Meridian, Idaho Appendix A Vicinity Map Site and Exploration Map ALLWEST Base Map:'dFo7ogle Earth,Imagery Date:07/13/2023�'/{ U OO C•.=�^ R�a�l�r c'.ri.x.T'..:— J.�7 'ram. _c' t•I luw { . `•F �n �'n�L�.. .��y}fH:.7 �._ "�i'13 �► J i '• rkuwi Y « III F- _ ?R� � _ 4 �!i �jY�G�i�i - 'Ik� x:•�,.:v.F��++Y��.1'�i�- ..si• IS E..t .�� s�{t`�•iC`�wI`_err .i?!T�g•2".i'.: •.i^,��':a..��• .i+K:+t-�r nSt�. * I�c� s ''• '�. 4+r '. iX'- - x �' 7iM s. �' r. - _ ".�L-� .�'1.'Wp.�r��+j,W�-�' y]�I�'"• ZITTl11i � � +n. -- r �.'F .rn •a`��.�s�'A� r'�.r,9la ii: �� �!y�ili . .J .�' y{ 7' •4R; 'L; -'+• '` l •` fl_ LL �l•r ' - 1 _{'II jr Site -E Old � �• r73 k a ���• ��t�-.T'.�'{!�. �. E�xik '� 4, •� J -�'� i fir., � i ,. r At A. i;. s ■ •�rsTi , , �l �v',a_ir �*vC�1,y.f 1..1."�c�'^ I. .1 r� - 1 _ As ��� �. � � i� 1-'�4_.rlF'r�. {. .1 II'� I. - _ }^ •. 1 Y� .f ZIP~ wf 1.�-• > >I •��'ULU �I' �__ IL` ..la�ssr I�I� .•r a'; `' O L't?.� I :� - -- I ► I I'I 7 3 r — �lu� I��rr Rf•. LZ;�:.�A ��jr,f^ - rT ' 1f f it '� s.r x �1x � t'w,s-•I '�� �, _ �}�_,=—_j L.. Rxwr,, far Q, r 4 r 1111X s'o f}'� _ y.'I„� 7. s r ww 71 I •illl, - ;,; I ..I• �or Vq -- UT. +A.A - '� 1 � •N o.�,Imo• r �'� L � 0' 2,500' 5,000' - FIGURE A-1:VICINITY MAP GEOTECHNICAL EVALUATION ALLWESTFARRINGTON HEIGHTS SUBDIVISION MERIDIAN, IDAHO 255 N.LINDER ROAD CLIENT:BLM VENTURE,LLC MERIDIAN,IDAHO 83642 PHONE:(208)895-7898 FAX:(208)898-3959 PROJECT NO.:524-69OG DATE:APRIL 2025 Base Map:Farrington Heights Subdivision, 1100, 1130,1180 E Pine Avenue, Meridian ID 83642,prepared by Studio H Architects,dated February 10,2025. (.E)1.G4TIUx ®uefi•xrsx•E 77 314.T6' R-15 ,d l O 3443 SF R-15 R-15 � R-15 � R-15 R-15 � R-15 i ns>xnirvnoexlx� 12904 SF 2803 SF 12800 SF 12563 SF 12825 SSF 13020 SF R- 2823 P-2 SF TI. R-15 i\�sts-J" 35.63 J— _3zo3 3s-3,- �T.Ts�.1 35.m• 2855 SF \ a ■ TP-1 EI PROPER LIRE COMMON E o RL._....._..:EET 2340 SFr R-15 a6. -- -- 4 2935 SF —--— za aa6,x.sr R_15 „I m R-15 tu s. R-15 3248 SF ml 0 3422 SF w " 2800 SF -- --afi oo� .�ee.6o•-- - -B R 15 R-15 =1 _ R-15 3168 SF - 3168 SF �I 0 2800 SF B -- - - --8006 Row 16-7 ■ TP-3 -15 68 3167 5SF � j168 5SFi (D OR/--15 —— —— 2800 SF Bi 96' 9806' --R15 e R-15S R-15 3344 SF m I 3344 SF 8 2800 SF n, - --0066 ■ TP-4 3267 SF °I R-15 ° s R-15 MI h 3324 SF t2851 SF _-- __ Tsoo'_ O Boundary R-15 NARDIMAN STRE o 3286 SF _ p --------- ----- ;T TP-5 0 sFj 1 O R-15 R-15 P s a 10983 SF o ���a�SF R-15 m ■ TP-6 (q SF RCSIDlNCC '� i i O o � s R-15 ® R-15 13541 SF g. 3853 SF R-15 (E)SF RESIDENC FERLFABUB EGOE5Ra8� 8541 SS \_� 6oMxoxoRw� �� I r (E)SF RESIDENCE 1 R-15 a 3845 SF II O � P ❑ n � R -314.5 E.PINE AVE. LEGEND Q Approximate location of test pit observed by ALLWEST. 0 90, 180, * Slotted PVC pipe was installed in test pit. FIGURE A-2:SITE AND EXPLORATION MAP GEOTECHNICAL EVALUATION ALLWESTFARRINGTON HEIGHTS SUBDIVISION MERIDIAN, IDAHO 255 N.LINDER ROAD CLIENT: BLM VENTURE, LLC MERIDIAN,IDAHO 83642 PHONE:(208)895-7898 FAX:(208)898-3959 PROJECT NO.:524-69OG DATE:APRIL 2025 Geotechnical Evaluation ALLWEST Project No. 524-69OG Farrington Heights Subdivision Meridian, Idaho Appendix B Exploration Logs Soil Classification Chart ALLWEST Farrington Heights Subdivision TP-1 ALL1rf EST Meridian, Idaho Page 1 of 1 Project No.: 524-69OG Client Name: BLM Venture, LLC Water Encounter: Contractor: Just Dig It Date Completed: 03/06/2025 N/A Equipment: Case 580C Depth: 10, Operator: Steve Just Logged By: Parker Norris Method: 24-inch-wide toothed bucketl Coordinates: 43.61372,-116.37748 Samples Lab F 0 0 y m Soil Description and Remarks r n c > c a J a � n m E O 2 m c 2)-j m Q m U (D cn LL a�a E U) 2 o 0 0 U) co 2 .J.i J N Q O TOPSOIL;abundant roots and organics;3 inches thick 0.3 LEAN CLAY with sand(CL), medium stiff,moist, Grab 25 76 32-20-12 1 brown 1.5 Silty SAND(SM), medium dense to dense,moist, 2 light brown 3 Weak to moderate cementation observed from 2 to 4.5 feet. 4 4.5 Poorly graded GRAVEL with Sand(GP),medium !�! 5 dense,moist,tan • •• Observed subrounded gravel and cobbles up to 6 0 .0 Grab 3 3 inches in maximum dimension. 6 �.4 461 Field infiltration test performed at 6 feet;rate>15 in/hr. •�.�• 7 ���• 8— ��.�• A'4 * 'I • .46 9 10 10.0 Test pit terminated due to caving.Slotted pipe installed. NOTES: Farrington Heights Subdivision TP-2 ALL1rf EST Meridian, Idaho Page 1 of 1 Project No.: 524-69OG Client Name: BLM Venture, LLC Water Encounter: Contractor: Just Dig It Date Completed: 03/06/2025 N/A Equipment: Case 580C Depth: 10.5' Operator: Steve Just Logged By: Parker Norris Method: 24-inch-wide toothed bucketl Coordinates: 43.61383,-116.37802 Samples Lab _ 0 _ J Q Soil Description and Remarks r mCU c CD E o a o m U) TOPSOIL;abundant roots and organics;3 inches thick 0.3 Lean CLAY with SAND(CL),medium stiff, moist, 1 brown 1.0 Silty SAND(SM), medium dense to dense,moist, light brown 2- 3- 4- Becomes tan at 4 feet. 5 Weak to moderate cementation observed from 5 to 6 feet. 6 6.0 Poorly graded GRAVEL with Sand(GP),medium dense,moist,tan •%•• Observed subrounded gravel and cobbles up to 6 0 • .�. inches in maximum dimension. 8 •�.�• ,4b-� •0.06 9 Okay A.4i;a� 10 10.5 Test pit terminated due to caving.Slotted pipe installed. NOTES: Farrington Heights Subdivision TP-3 ALL1rf EST Meridian, Idaho Page 1 of 1 Project No.: 524-69OG Client Name: BLM Venture, LLC Water Encounter: Contractor: Just Dig It Date Completed: 03/06/2025 N/A Equipment: Case 580C Depth: 10, Operator: Steve Just Logged By: Parker Norris Method: 24-inch-wide toothed bucketl Coordinates: 43.6134,-116.37755 Samples Lab F 0 0 y m Soil Description and Remarks r n c > c a J a � n m E O 2 m c 2)-j m Q m U (D cn LL a�a E U) 2 o 0 0 U) co 2 .J.i J N Q O TOPSOIL;abundant roots and organics;3 inches thick 0.3 Sandy lean CLAY(CL),medium stiff,moist,brown7� 1 Bulk 20 59 29-21-8 1.5 Silty SAND(SM), medium dense to dense,moist, 2 light brown Grab 30 17 3 Becomes tan at 3.5 feet. 4 Moderate cementation observed from 3.5 to 5 feet. 5 5.0 Poorly graded GRAVEL with Sand(GP),medium !�! dense,moist,tan • •• Observed subrounded gravel and cobbles up to 10 • • ••,6—inches in maximum dimension. Field infiltration test performed at 6 feet;rate>15 :�• in/hr. • • 7 •..• a�� •�.• 8 A.4 0* g !4 10 10.0 �• Test pit terminated due to caving. NOTES: Farrington Heights Subdivision TP-4 ALL1rf EST Meridian, Idaho Page 1 of 1 Project No.: 524-69OG Client Name: BLM Venture, LLC Water Encounter: Contractor: Just Dig It Date Completed: 03/06/2025 N/A Equipment: Case 580C Depth: 10, Operator: Steve Just Logged By: Parker Norris Method: 24-inch-wide toothed bucketl Coordinates: 43.6132,-116.37803 Samples Lab 0 J Q C N � Soil Description and Remarks r CL n m E o m m c o m Q m U co LL (D E o 0 m � J N O TOPSOIL;abundant roots and organics;3 inches thick 0.3 Lean CLAY with sand(CL),medium stiff, moist, 1 brown 1.0 Silty SAND(SM), medium dense to dense,moist, light brown 2 Weak to moderate cementation observed from 2.5 to 3 3.5 feet. 3.5 Poorly graded GRAVEL with Sand(GP),medium !�! 4 dense,moist,tan • •• Observed subrounded gravel and cobbles up to 8 • • •• inches in maximum dimension. •� •• Grab 5 3 5 Field infiltration test performed at 5 feet;rate>15 in/hr. •�.•• 6 ���• �46� bft. A 7 •�.• 8 9 • ' •• ��� 10 10.0 Test pit terminated due to caving.Slotted pipe installed. NOTES: Farrington Heights Subdivision TP-5 ALL1rf EST Meridian, Idaho Page 1 of 1 Project No.: 524-69OG Client Name: BLM Venture, LLC Water Encounter: Contractor: Just Dig It Date Completed: 03/06/2025 N/A Equipment: Case 580C Depth: 10, Operator: Steve Just Logged By: Parker Norris Method: 24-inch-wide toothed bucketl Coordinates: 43.61298,-116.37725 Samples Lab _ 0 _ J Q Soil Description and Remarks r mCU c CD E o a o m U) TOPSOIL;abundant roots and organics;3 inches thick 0.3 Lean CLAY with sand(CL),medium stiff, moist, 1 brown 1.0 Silty SAND(SM), medium dense to dense,moist, light brown 2- 3- Weak to moderate cementation observed from 3.5 to 4 5.5 feet. 5 5.5 Poorly graded GRAVEL with Sand(GP),medium �! 6 dense,moist,tan • •�• Observed subrounded gravel and cobbles up to 6 .1 • .4. inches in maximum dimension. 7 A. 8 I%. A 9 •S.• 10.0 10 Test pit terminated due to caving.Slotted pipe installed. NOTES: Farrington Heights Subdivision TP-6 ALLIET Meridian, Idaho Pagel of 1 Project No.: 524-69OG Client Name: BLM Venture, LLC Water Encounter: Contractor: Just Dig It Date Completed: 03/06/2025 N/A Equipment: Case 580C Depth: 9' Operator: Steve Just Logged By: Parker Norris Method: 24-inch-wide toothed bucketl Coordinates: 43.61277,-116.37747 Samples Lab o 4 n w E= n Soil Description and Remarks Q o m rna o c� Q m U U U) U- `ma m -0 � o o ate`)m U) rn J Q O TOPSOIL;abundant roots and organics;3 inches thick 0.3 FAT CLAY with sand(CH),medium stiff,moist,dark Grab 29 so 55-21-34 1 brown 1.5 Silty SAND(SM), medium dense to dense,moist, 2 light brown 3 Weak to moderate cementation observed from 3 to 4 feet. 4 4.0 Poorly graded GRAVEL with Sand(GP),medium ! ! dense,moist,tan •• Observed subrounded gravel and cobbles up to 6 s• 5 inches in maximum dimension. .6 A 0�.�• 6 ��•�• 7 �U.Q• � l 6Vi .. 9.0 9 �• Test pit terminated due to caving. NOTES: SOIL CLASSIFICATION CHART (ASTM D2487 & D2488) MAJOR GROUP TYPICAL SOIL NAMES TYPICAL SOIL DESCRIPTORS DIVISIONS SYMBOL GW Well-graded gravel,gravel-sand mixtures,little or no fines. Description SPT Blow Counts O Very loose less than 4 Loose 4 to 10 w GP Poorly-graded gravel,gravel-sand mixtures,little or no fines. Medium dense 11 to 29 C3� > O Dense 30 to 50 Very dense greater than 50 0 o O GM Silty gravel,gravel-sand-silt mixtures. o Material Sieve Sizes CC14 Boulders greater than 12" w r GC Clayey gravel,gravel-sand-silt-clay mixtures. Cobbles 3"to<12" z � Q o Coarse gravel 3/4"to<3" Fine gravel #4 to<3/4" SW Well-graded sand,gravelly sand,little or no fines. Coarse sand <#4 to#10 Medium sand <#10 to#40 Q w Fine sand <#40 to#200 oo SP Poorly-graded sand,gravelly sand, little or no fines. Silt or clay less than#200 n ¢ Sieve Number Aperture SM Silty sand,sand-silt mixtures. #4 4.76 mm(0.187 in) #10 2.00 mm(0.0787 in) #40 0.42 mm(0.0165 in) SC Clayey sand,sand-clay mixtures. #200 0.074 mm(0.00291 in) ML Inorganic silt,non-plastic to low plasticity,gravelly silt, Description SPT Blow Counts Q LO sandy silt,clayey silt. v Very soft less than 2 U '= Soft 2 to 3 o E Inorganic clay of low to medium plasticity,gravelly clay, v� o z i CL sandy clay,silty clay(CL-ML),lean clay. Medium stiff 4 to 8 J N Q -0 Stiff 9 to 15 r J J Very stiff 16 to 29 o - r OL Organic silt and organic silty clay of low plasticity. Hard 30 to 50 Lu z =; r Very Hard greater than 50 0 L MH Inorganic silt,micaceous or diatomaceous fine sandy or Plasticity Soil Characteristics C7 Q silty soils,elastic silt. uw °�' A Non-plastic Cannot be rolled at any water content. Qo : Low A thread can barely be rolled while moist. z 1D CH Inorganic clay of high plasticity,fat clay. Medium A thread can be rolled easily but cannot be o rerolled after reaching the plastic limit. J a High A thread can be rolled and re-rolled several F OH:-:: Organic clay of medium to high plasticity. times after reaching the plastic limit. Definitions ORGANIC SOILS W PTy Peat and other highly organic soils. Liquid Limit(LL) Moisture content at which soil changes state from plastic to liquid. Plastic Limit(PL) Moisture content at which soil Dry Absence of moisture in sample. Dusty,dry to the touch. changes state from semi-solid to plastic. Plasticity Index(PI) Range of moisture contents at which Slightly Moisture in sample is below the optimum moisture content. a soil behaves plastically(LL-PL-PI). Moist Grains adhere slightly though surface tension. MOISTURE Moist Moisture in sample is at or near optimum moisture content. PLASTICITY CHART (ASTM D4318) No free water is visible. Moisture in sample is above the optimum moisture content. a 50 Wet Free water is visible in sample. w 0 o G� Weak Crumbles or breaks with handling or slight finger pressure. � CL-ML i CL MH or OH CEMENTATION Moderate Crumbles or breaks with considerable finger pressure. a a ML 0 0 16 50 Strong Will not crumble or break with finger pressure. LIQUID LIMIT(LL) ALLWEST Geotechnical Evaluation ALLWEST Project No. 524-69OG Farrington Heights Subdivision Meridian, Idaho Appendix C Laboratory Test Results ALLWEST Table C-1: Summary of Laboratory Test Results Moisture Gradation Atterberg Limits Test Pit Depth Content Gravel Sand Silt/Clay Liquid Plastic Plasticity CBR Sample Classification � (Feet) M (%) N N Limit Limit Index (/o) (USCS) (/o) (/o) (/o) TP-1 0.5-1.5 25 76 32 20 12 Lean CLAY with sand CL TP-1 5-5.5 3 3 Poorly graded GRAVEL with sand GP TP-3 0.5-1.5 20 59 29 21 8 17.0 Sandy lean CLAY CL TP-3 2.5-3 30 17 Silty SAND SM TP-4 4.5-5 5 3 Poorly graded GRAVEL with sand GP TP-6 0.5-1 29 80 55 21 34 Fat CLAY with sand CH 255 N. Linder Road • 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.