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Home My WebLink AboutSubsoil Studyffi OTL I THOMPSONW RECE,VED FFB t 2 2022 .t'îf,ñ',f rt?,ip#},.iy GEOTECHNICAL ENGINEERING INVESTIGATION BROWN RESIDENCE 2685 ELK SPRINGS DRIVE (a.k,a. ELK SPRINGS SUBDIVISION, LOT 15, FIL|NG B) GARFIELD COUNTY, COLORADO Prepared For: DAVID BROWN c/o STRYKER BROWN ARCHITECTS, P.C. 225 N. Mill Street, Suite 100 Aspen, CO 81611 Project No. GS065i21 .00A-120 January 14,2021 234 Center Ðrive I Glenwood Springs, Colorado 81601 Telephone: 970-945-2809 Fax: 970-945,741 1 ffi TABLE OF CONTENTS SCOPE...,. SUMMARY OF CONCLUSIONS SITE CONDITIONS PROPOSED CONSTRUCTION SÍTE GEOLOGY SUBSURFACE CONDITIONS SITE EARTHWORK ¡.,I¡Ir¡r.¡¡.r !¡. Excavation Structural Fill ....,....... Foundation Wall 8ackfi11 .......,....... FOUNDAT|ON.......,,.. SLABS-ON-GRADE CONSTRUCTION...... STRUCTURAL FLOORS AND CRAWL SPACES, FOUNDATTON WA11S............... ... SUBSURFACE DRAINAGE ... J¡, ;¡,. !. SURFACE DRAINAGE coNcRETE .............. CONSTRUCTION OBSERVATIONS STRUCTURAL ENGINEERING SERVICES . GEOTECHNICAL RISK......... LtMtrATtoNS............ ¡ri;1....r! ¡l¡..¡.r.¡;!1 1, 2 3 3 4 6 6 7 7 8 I I .... 10 ....11 ....12 ....13 ....'t3 ....14 ,...14 ...15 FIGURE 1-VICINITYMAP FIGURE 2 _ AERIAL PHOTOGRAPH FIGURE 3 - SUMMARY LOGS OF EXPLORATORY PITS FIGURE 4 - GRADATION TEST RESULTS FIGURE 5 _ FOUNDATION WALL DRAIN CONCEPT TABLE I - SUMMARY OF LABORATORY TESTING DAVID BROWN BROWN RESIDENCE PROJECT NO, cS06s21.000-120 ffi SCOPE This report presents the results of our geotechnical engineering investiga- tion for the Brown Residence proposed at 2685 Elk Springs Drive (a.k.a. Elk Spríngs Subdivision, Lot 15, Filing 8) in Garfield County, Colorado. We conducted this investigation to evaluate subsurface conditions at the site and provide ge- otechnical engineering recommendations for the proposed construction. The scope oi our investigation was set forth ín our Proposal No. GS 2O-A319. Our re- port was prepared from data developed from our field exploration, laboratory tesl ing, engineering analysis and our experience with similar: conditions. This report includes a description of the subsurface conditions observed in the exploratory pits and presents out'geotechnical engineering recommendations for design and con- struction of foundations, floor systems, belowgrade walls, and details influenced by the subsoils. We should be provided wÍth architectural plans, as they are devel- oped, so that we can provide geotechnical/geo-structural engineering input. A summary of our conclusions is presented below. SUMMARY OF CONCLUSIONS Subsurface conditiohs observed in our exploratory pits excavated at the site consisted of about 3-inches of topsoil over basalt boulders, cobbles and gravel in a matrix of sandy clay and silt. Densely-nested boulders prevented excavation deeper than 4 and 5 feet in our pits. Free groundwater was not found in the exploratory pits. We anticipate excavations at this site will be more difficult than usual due to the dense cobbles and boulders. Voids resulting from removal of lar"ge boulders should be filled with densely-compacted, granular structural fill. Additionally, the large amount of cobbles and boulders in the natural soil may result in a significant percentage of the exca- vated soils that are unsuitable for reuse as fill and backfill. We judge footing foundations are appropriate for the residence. The footings should be supported by the undisturbed, natural soils or densely-compacted granular, structural fill. Desig n and construction criteria for footings are presented in the report. DAVID BROWN BROWN RESIDENCE PROJECT NO. GS06521.000-1 20 1 2 3. 1 ffi 4 5 we expect slab-on-grade constrùction can be supported by the un, disturbed, natural sojls or densery-compacted, granular structural fill provided the fill is placed as recommended in the report, Additional discussion is in the report. The residence should be provided with a perimeter foundation drain around below-grade areas. surface drainage should be designed and constructed to rapidly convey surface water away from the resi- dence. SITE CONDITIONS The Brown Residence is proposed, at 2685 Elk springs Drive (a.k.a. Elk springs subdivision, Lot 15, Filing B) in Garfield county, Colorado. A vicinity map with the location of the site is shown on Figure 1. The site is south of the intersec- tion of EIk Springs Drive and Juniper Drive. An aerial photograph is Íncluded as Figure 2. Ground surface in the building envelope generally slopes down to the west and southwest at grades less than 10 percent. Steeper slopes are south and west of the envelope. A natural drainage swale trends down to the south along the west property boundary. Vegetation on the gentle slopes consists of grasses and sage. Finyon and Juniper are on the steep slopes. Several inches of snow were on the ground at the time of our subsurface investigation. A photograph of site conditions is below. DAVID BROWN BROWN RESIDENCE PROJECT NO. cS06521,000-120 2 : î : : Ì l ffi PROPOSED CONSTRUCTION Building plans for the Brown Residence were not developed at this writing. We understand the residence will be a one and two-story, wood-framed building with an attached garage. A crawl space is proposed below the main level of the residence. A slab-on-grade floor is expected in the garage. Maximum foundation excavation depths will likely be less than 15 feet. Typical foundation loads for this type of construction are about 1,0CI0 to 3,000 pounds per lineal foot of foundation wall with maximum interior column loads of less than 50 kips, We should be pro- vided with architectural plans, as they are developed, so that we can provide ge- otechnical/geo-structural engineering input. SITE GEOLOGY As part of our geotechnical engineering investigation, we reviewed geologic mapping by the colorado Geological survey titled, "Geologic Map of the catfle Creek Quadrangle, Garfield County, Colorado", by Kirkham, Streufert, Hemborg, DAVID BROWN BROWN RESIDENCE PROJECT NO. GS06521"000-120 3 ffi Thomas, and Stelling (dated 2014). The mapping indicates the site is underlaín by basalt deposited by volcanic flows, The upper: rock is fractured and weathered into boulders and cobbles. These rocks are in a matrix of sheetwash deposits of grav- elly sand, sandy silt, and clayey silt. Subsurface conditions encountered in our ex- ploratory pits are consistent with the geologic mapping. We also reviewed the CGS mapping, "Collapsible Soils and Evaporite Karst l-lazards Map of the Roaring Fork River Corridor, Garfield, Eagle and pitkin Coun- ties, Colorado", by Jonathan L. White (dated 2002). The map indicates the subject site is in an area of unconsolidated surficial deposits that includes outwash depos- its^ These depoqits are geologicaily, recent and typically loosely-packed, porous .and dr[. ln many cases, the soils have a potential collapse when wetted under load. Our subsurface investigation indicates the soils at the subject site are clast- supported by the basalt cobbles and bedrock with outwash materialfilling the voids between the rocks. We judge the potential for soil collapse is low at this site. SUBSURFACE CONDITIONS Subsurface conditions at the site were investigated by observÍng excavation of two exploratory pits (TP-1 and TP-2), The pits were excavated with a trackhoe at the approximate locations shown on Figure 2. Exploratory excavation opera- tions were directed by our engineer, who logged subsurface conditions encoun- tered and obtained samples of the excavated soils. Graphic logs of the soils en- countered in our exploratory pits are shown on Figure 3. Subsurface conditions observed in our exploratory pits consisted of about 3-inches, topsoil over basalt boulders, cobbles and gravel in a matrix of sandy clay and silt. Densely-nested boulders prevented excavation deeper thai 4 and 5 feet in TP-1 and TP-2, respectively. Free groundwater was not found in our exploratory DAVID BROWN BROWN RESIDENCE PROJECT NO. cS06521.000-,r 20 4 ffi pits at the time of excavation. The pits were backfilled immediately after excava- tion operations were completed. A photograph of conditions found in TP-1 is be- low. Samples of the soils obtained from our exploratory pits were returned to our laboratory for pertinent teçting. Two samples of the soils selected tor gradation analysis contained 46 and 29 percent gravel, 26 and 30 percent sand, and 28 and 41 percent silt and clay (passing the No. 200 sieve), Gradation tests are not inclu- sive of l"ocks larger than 5 inches and representative of the matrix soil. We judge the soils are composed predominantly of cobbles and boulders. Gradation test re- sults are shown on Figure 4. Engineering index testing on one sample of the ma- trix soil indicated low plasticity with a liquid limit of 51 percent and a plasticity index of 20 percent. Based our laboratory testing and our experience at nearby sites, the matrix soil has low to moderate potentialfor expansion when wetted. Laboratory test results are summarized on Table l. DAVID BROWN BROWÑ RESIDENCEpRoJECT NO. GSo652,t.000-1 20 5 : l ffi SITE EARTHWORK Excavation Excavation depths for the building are expected to be less than 15 feet. We anticipate excavations at this site for the building and underground utilities will be more difficult than usual due to the dense cobbles and boulders. Heavy-duty exca- vation equipment will be necessary. Excavations may require or be most efficien¡y made with blasting to loosen the ssils. Large boulders should be expected. Voids below the building resulting from removal of large boulders should be filled with densely-compacted, granular structural fitl in accordance with recommendations in the Structural Eill section. From a "trench" safety standpoint, sides of excavatíons need to be sloped or braced to meet local, state and federal safety regulations. The soils encoun- tered in the excavation to construct the residence will likely classify as a Type C soil based on osHA standards governing excavations. Temporary slopes deèper than 5 feet that are not retained should be no steeper than 1.5 to 1 (horizontal to vertical) in Type C soils. Contractors are responsible for determining the actual OSHA soiltype when excavations are made and for maintaining safê excavatiorrs lf the sídes of the foundation excavatisn cannot be laid back, an earth retention system, such as soil nails or micropiles will be required. Free groundwater was not found In our exploratory pits. We do not antici- pate excavations for foundations or utilities will penetrate groundwater. We recom- mend against excavation during snowmelt. Excavations should be sloped to a gravity discharge or to a temporary sump whe¡.e water from precipitation and snowmelt can be removed by pumping. The ground surrounding the excavations should be sloped to direct runoff away from the excavations. DAVID EROWN BROWN RESIDENCE PROJECT NO. GSo6521.000-120 6 ffi Structural Fill Structuralfillmay be required below some areas of the building and exterior flatwork and to raise grades and/or fill voids resulting from removal of large boul- ders. Areas that receive fill should be strípped of vegetation, organic soils and de. brís. Structural fill below the building should consist of a CDOT Class 6 aggregate base course or simìlar soil. The excavated soils, free of rocks larger than 3 inches in diameter, organic matter, and debris can be used as structuralfill outside of the building footprint. Structural fill should be placed in loose lifts of 8 inches thick or less and moisture-conditioned to within 2 pereent of optimum moisture content. Structural fill should be compacted to at least 98 percent of standard Proctor (ASTM D 698) maximum dry density. Moísture content and density of structural fill should be checked by a representative of our firm during placement. Observation of the com- paction procedure is necessary. Testing without observation oan lead to undesira- ble performance. Foundation Wall Backfill Proper placement and compaction of foundation backfill is important to re, duce infiltration of surface water and settlement of backfill. Backfill oompaction is especially important in areas that will support exterior slabs-on-grade, such as driveways and patios. The natural soils can be used as backfill, provided they are free of rocks larger than 3-inches in diameter, organics, and debris. Backfill should be placed ín loose lifts of approximately 10 inches thick or less, moisture-conditioned to within 2 percent of optimum moisture content and compacted. Thickness of lifts will likely need to be about 6 inches if there are small confined areas of backfill, which limit the size and weight of compaction equipment. Backfill should be compacted to at DAVID BROWN BROWN RESIDENCE PROJEÇT NO. GS06521.000-120 7 ffi least 95 percent of maximum stândard proctor (ASTM D 69g) dry density. Msis- ture content and density of the backfill should be checked during placement by a representative of our firm. Observation of the compaction procedure is necessary FOUNDATION Based on our subsuface information from the site, we judge footing foun- datíons are appropriate for the residence. The footings can be supported direc¡y on the undisturbed, natural soil. Voids resulting from removal of large boulders should be filled with densely-compacted, granular structuralfill in accordance with recommendations in the Structural Fill section. The completed foundation excava- tion should be observed by a representatíve of our firm, prior to placing forms, to confirm that the subsoils are as anticipated and suitable for support of the de- signed footings. Recommended design and construction criiería for footings are presentêd below. Footing foundations should be supported by the undisturbed, natural soils or densely-compacted granular, structural fill. soils loosened during excavation or the forming process for the footings should be removed or the soils can be re-compacted prior to placing concrete. Footings on the undisturbed, natural soils or densely-compacted, granular structural fill should be designed for a maximum allowable soil pressure of 3,000 psf. continuous wallfootings should have a minimum width of at least 16 inches. Foundations for isolated columns shourd have minimum di- mensions of 24 inches by 24 inches. Larger sizes may be required, depending upon foundatíon loads, Grade beams and foundation walls should be well reinforced, top and bottom, to span undisclosecl loose or soft soil pockets. we rec- ommend reinforcement sufficient to span an unsupported distance of at least 10 feet. 1 2 3 4 5. DAVID BROWN BROWN RESIDENCE PROJECT NO. GS06521.000-120 The soils beneath exterior footings shourd be protected from freez- ing. we recommend the bottom of footings be constructed at a depth I ffi of at least 36 inches below finished exterior grades. The Garfield County building department should be consulted regarding required frost protection depth. SLABS-ON.GRADE CONSTRUGTION A slab-on-grade flosr is expected in the garage. We judge slab-on-giade construction can be supported by the undisturbed, natural soils or densely-com- pacted, granular structural fill. The structural fill below slabs should be placed in accordance with recommendations in the Stnr ral Fill section, We recommend the following precautions for slab-on-grade construction at this site. Slabs should be separated from exterior walls and interior bearing members with slip joints which allow free vertical movement of the slabs. The use of underslab plumbing should be minimized. Underslab plumbing should be pressure tested for leaks before the slabs are constructed, Plumbing and utilities which pass through slabs should be isolated from the slabs with sleeves and provided with flexible couplings to slab supported appliances. Exterior concrete flatwork should be isolated from the residence. These slabs should be well-reinforeed to function as independent units, Frequent controljoints should be provided, in accordance with Amer- ican Concrete lnstitute (ACl) recommendations, to reduce problems associated with shrinkage and curling. STRUCTURAL FLOORS AND CRAWL SPACES We understand that crawl spaces will be constructed below the main level floors. Where structurally-supported floors are installed over a crawlspace, the re- quired air space depends on the materials used to construct the floor. Building codes require a clear space of 18 inches between exposed earth and untreated DAVID BROWN BROWN RESIDENCE PROJECT NO. GSo6521-000-1 20 1 2 3. 4 I ffi wood floor components. For non-org-anic systems, we recommend a minimum clear space of 18 inches. Where structurally supported floors are used, utility con- nections, including water, gas, air duct, and exhaust stack connections to floor supported appliances, should be capable of absorbing some deflection of the floor. Control of humidity in crawl spaces is important for indoor air quality and performance of wood floor systems. We believe the best current praotices to con- trol humidity involve the use of a vapor retarder or vapor barrier (10 mil mínimum) placed on the soils. The vapor retarderlbarrier should be sealed at joints and at- tached to concrete fôundation elements. An active ventilation system controlled by a hurnidistat is beneficial. FOUNDATION WALLS Foundation walls which extend below-grade should be designed for lateral earth pressures where backfill is not present to about the same extent on both sides of the wall, such as in crawl space areas, Many factors affect the values of the design lateral earth pressure. These factors include, but are not limited to, the type, compaction, slope and drainage of the backfill, and the rigidity of the wall against rotation and deflectíon. For a very rigid wall where negligible or very little deflection will occur, an "at-rest" lateral earth pressure should be used in design. For walls which can de- flect or rotate 0.5 to 1 percent of wall height (depending upon the backfill types), lower "active" lateral earth pressures are appropriate. Our experience indicates typical below-grade walls can deflect or rotate slightly under normaldesign loads, and that this deflection results in satisfactory wall peforrnance, Thus, the earth pressures on the walls will likely be between the "active" and "at-rest" conditions. DAVID BROWN BROWN RESIÐENCE PROJECT NO. GS06521.000.120 l0 ffi For backfill conforming to recommendations in the Foundation Wall Backfill section that is not saturated, we recommend design of bêlow-grade walls using an equivalent fluid density of at least 45 pcf for this site. This equivalent density does not include allowances for sloping backfitl, surcharges or hydrostatic pressures. The recommended equivalent density assumes deflection; some minor cracking of walls may occur. lf very líttle wall deflection is desired, a higher equivalent fluid density may be appropriate for design. SUBSURFAGE DRAINAGE water from surface precipitation, snowmelt, and irrigation frequently flows through relatively permeable backfill placed adjacent to a residence and collects on the surf¿ce of less permeable soils occurring at the bottom of foundation exca- vations. This process cân cause wet or moist condítions in below-grade areas, such as basement and crawl spaces, after construction. We recommend an exterior foundation wall drain be installed around the perimeter of the crawl space areas in the residence. The exterior foundation drain should consist of 4-inch diameter, slotted, pvc pipe encased in fr.ee-draining gravel. A prelabricated drainage composite should be placed adjacent to founda- tìon walls. Care should be taken during backfill operations to prevent damage to drainage composites. The drain should discharge via a positive gravity oulet, or lead to a sump pit wher:e water can be removed by pumping. Gravity ouflets should not be susceptible to clogging or freezing. lnstallation of clean-outs along the drain pipes is recommended. The foundation walldrain concept is shown on Figure 5. DAVIO BROWN BROWN RESIDENCE PROJECT NO. cS06521.000-120 11 ffi SURFACE ÞRAINAGE Surface drainage is critical to the performance of foundations, floor slabs, and concrete flatwork. Surface drainage should be designed to provide rapid run- off of surface water away from the ¡'esidence" Proper surface drainage and irriga- tion practices can help control the amount of surface water that penetrates to foun- dation levels and contributes to settlement or heave of soils and bedrock that sup- port foundations and slabs-on'grade. Positive drainage away from the foundation and avoidance of irrigation near the foundation also help to avoid excessive wet- ting of backfill soils, which can lead to increased backfill settlement and possibly to higher lateral earth pressures, due to increased weight and reduced strength of the backfill. We recommend the following precautions. The ground surface surrounding the exterior of the residence shourd be sloped to drain away from the building in all directions. We recom- mend a minimum constructed slope of at least 12 inches in the first 10 feet (10 percent) in landscaped areas around the residence, where practical. Backfill around the foundation walls should be moistened and com- pacted pursuant to recommendations in the Foundation wall Backfill section. The residence should be provided with roof gutters and downspouts. Roof downspouts should discharge well beyond the limits of alr back- fill. splash blooks and/or extensions slrould be provided at ail down- spouts so water discharges onto the ground beyond the backfill. we generally recommend against burial of downspout discharge. Where it is necessary to bury downspout discharge, solid, rigid pipe should be used, and the pipe should slope to an open gravity ouflet. lrrigation should be limited to the minimum amount sufficient to main- tain vegetation; application of more water will increase lilcelihood of slab and foundation movements. Plants placed close to foundation walls should be limited to those with low moisture requirenrents. lrri- gated grass should not be located within 5 feet of the foundation. sprinklers should not discharge within 5 feet of foundations. prastic sheeting should not be placed beneath landscaped areas adjacent to foundation walls or grade beams. Geotextile fabric wiil inhibit weed gr"owth yet still allow natural evaporation to occur. 1 2 3 4 DAVID BROWN BROWN RESIDENCE PROJECT NO. GSo6521.000-120 12 ffi CONCRETE Concrete in oontact with soil can be subject to sulfate attack. We measured a water-soluble sulfate concentration of 0.0 percent in one sample of the clay from the site. For this level of sulfate concentration, ACI 332-08, Code Requirements for Residential Concrete, indicates there are no special requirements for sulfate re- sistance. ln otlr experience, superficial damage may occur to the exposed surfaces of h.ighly-permeable concrete, even though sulfate levels are relatively low. To con- trol this risk and to resist freeze-thaw deteríoration, the water-to-cementitious ma- terials ratio should not exceed 0.50 for concrete in contact with soils that are likely to stay moist due to sudace drainage or high-water tables. Concrete should have a total air content of 6% +l- 1.5o/o. We recommend all foundation walls and grade beams in contact with the subsoils be damp-proofed. CONSTRUCTION OBSERVATIONS We recommend that CTL I Thompson, lnc. be retained to provide construc- tion observation and materials testing services for the project. This would allow us the opportunity to verifu whether soil conditions are consistent with those found during this investígation. lf others perform these observations, they must accept responsibility to judge whether the recommendations in this report remain appro. priate. lt is also beneficialto projects, from economic and practical standpoÍnts, when there is continuity þetween engineering consultation and the construction observation and materials testing phases. ÞAVIÐ BROì¡VN BROWN RESIDENCE PROJECT NO. cS06521.000-,t20 13 ffi STRUCTURAL ENG¡NEERING SERVICES CTL I Thompson, lnc.is a full-service geotechnical, structural, materials, and environmental engineering firm. Our services include preparation of structural framing and foundation plans. \rVe can also design temporary and permanent earth retention systems. Based on our experience, cTL I Thompson, lnc. typically pro- vides value to projects from sehedule and economic standpoints, due to our com- bined expeñise and experience with geotechnical, structural, and materials engi- neering. We can provide a proposal for structural engineering services, if re- quested. GEOTECHN¡GAL RISK The concept of risk is an importânt aspect of any geotechnical evaluation. The primary reason for this is that the analytical methods used to develop ge- otechnical recommendations do not comprise an exact science. The analytical tools which geotechnical engineers use are generally empirical and must be tem- pered by engineering judgment and experience. Therefore, the solutions or recom* mendations presented in any geotechnical evaluation should not be considered risk-free and, more importantly, are not a guarantee that the interaction between the soils and the proposed structure will perform as desired or intended, The engi- neering recommendations presented in the preceding sections constitute our estÍ- mate of those measures necessary to help the building perform satisfactorily. This report has been prepared for the exclusive use of the client for the pur- pose of providing geotechnical engineering design and construction criteria for the proposed residence. The information, conclusions, and recommendations pre- sented herein are based upon consideration of many factors including, but not lim- ited to, tlre type of structures pr"oposed, the geologic setting, and the subsurface conditions encountered. The conclusions and recommendations contained in the report are not valid for use by others. Standards of practice continuously change in DAVID BROWN BROWN RESIDENCE PROJECT NO. GS06521.000-120 14 ffi the area of geotechnical engineering. The recommendations provided in this report are appropriate for about three years. lf the proposed project is not eonstructed within three years, we should be contacted to determine if we should update this report. LIMITATIONS The exploratory pits provide a reasonable characterization of subsurface condítions at the site. Variations in the subsurface conditions not indicated by thê pits will occur. We should be provided with architectural plans, as they are devel- oped, so we can provide geotechnical/geo-structural engíneering ínput: This investigation was conducted in a manner consistent with that level of ca!'e and skill ordinarily exercised by engineering geologists and geotechnicalen- gineers currently practicing under similar conditions ih the locality of this project. No other warranty, express or implied, is made. lf we can be of further service in discussing the contents of this report, please call. cTL I THOMPSON, tNC.Reviewed by: k.k Staff Engineer zmes D. Kel Division Man RWD:JDK:abr DAVID BROWN BROWN RESIOENCE PROJËCT NO. GS06521,000-1 z0 l5 ffi 0 2000 2000qErq!NOTE: SCALE: 1i - 20ö0' DAVIDBROWN EROr/yN FESìI¡ËNoE PROJECT NO. CSO6521.000.1 20 SATELLITE IMAGE FROM GOOGLE EARTH (pnren JUNE 2o1z) Vicinity Map Ftg. 1 LEGEND: TP-1 APPROXIMATE LOCATION OFt EXPLoRAToRY ptr ffi APPROXIMATE PROPERTY BOUN.DARY o 60 100trFtrTt NOTE: SCALE: 1r F 100' DAVID BROWN BRo\/I'N EEsIDENCË PROJECï NO. GSO6521.OOO-1 20 SATELLITE IMAGE FROM GOOGLE EARTH (DATED JUNE 2017) Aerial TP.2 TP*1 Photograph Flg. 2 TP-1 TP.2 TOPSOIL, SAND, CLAYEY, GMVEL, oRGANtcS, LOOSË, MotsT, DARK BROWN, BASALT BOULDERS, COBBLES AND GRAVEL, SANDY CLAY AND SILT MATRIX, DENSE, MOIST, BROWN, GRAY, CALCAREOUS, INDICATES BULK SAMPLE FROM EXCAVATED SOILS. PRACTICAL REFUSAL ON BOUDLERS. ffi 9ummary Logs of Fì[g'o'atóry FIG.3 LEGEND: t¡ltr I F"(L l,¡.1 Éì 0 5 10 0 5 10 l- I-l JqlË I r.ulô l _l F NOTES: 1, EXPLORATORY PITS WERE EXCAVATÊI) WTH A TRACKHOE ON DËOËMBER 23, 2020. PITS WERE BACKFITLEÐ IMMEDIATELY AFTER EXPLORATORY EXCAVATION OPERATIONS WERE COMPLETED. 2, GROUNDWATERWAS NOTFOUND INOUR EXPLoRAToRY PITS AT THE TIME oF EXCAVATION. 3. LOCATIONS OF EXPLORATORY PITS ARE APPROXIMATE. 4" EXPLoRAToRY FITS ARE SUBJECT TO THE EXPL.ANATIONS, LIMITATIONS AND CONCLUSIONS CONI-AINED IN THIS RËPORI', DAVID BROWN BROWN RESIDENOE PROJECT NO, GSO6C21 .000-1 20 ffi SANOS GRAVELclAY (PLASTTC) TO StLT (NON-pLASflC) FINE MEOIUM COARSE FINE COARSE I COBBLES HYDROMËTERANALYSIS SIEVE ANALYSIS .001 0,002 .005 .009 .019 .037 .s74 .'t49 .2970,42.59ç 1"19 2.0 2.38 4.76 9.52 DIAMETER OF PARÎ¡CLE IN MILLIMETERS _t_ -----------+---, -t-,,--l_- ___t-, -¡-___-_l_L_ -t-;-*-t__ , ------l- --+_|_ -t-+__ _t. __ __t__t_ --t--j' ------------t--, ____,,_-lJ_ _J=-.. L_ _t- lo I fIME 427 200 152 90 80 0 U.sl 100 '4 3/8. 3r4" 1%' 3' 30 10 80 90 100 1 76.2 5f6il I'r SERIES '16 -10 .8 10 2ß ô30uz 340 i! É. ts 50ı(] É,U60ù 70 80MlN. 19M¡N, 4 MtN. 1 MtN, .2oO .1oO .50 r40 .30 25 HR. 7 ilR. 45 MlN. 15 MtN. Somple of GRAVEL, cLAyEy (cC)From Tp-1 AT 3-4 FEET Somple of SAND, slLTy (sM)From TP-z AT 4-5 FÈET ERAVEL 46 SILT & CLAY PLASTICITY INDEX GRAVEL 29 o/o srLT & CLAY 41 % PLASTICITY INDEX % SAND % LIQUID LIMIT SAND LIQUID LIMIT 26 o/o % % 30% o/ o/o DAVID BROWN BROWN RESIDENCE PROJECT NO. GS06521.000-120 Gradation Test Results SANDS GRAVELCLAY (PLASTTC) To SrLr (NON-PLAST|C) FINE MËDIUM COARSE FINE COARSE COBBLES ('/0zØØ Í60 Fz 850 É.Uo¡o 76.2 127 200 '152 8" 0 80 90 80 90 100 100 10 20 30 40 50 60 70 ,001 0.002 .005 .009 .019 .a37 9.52 r9.1 36.1 TIMË RÊAOINGS 60 MlN. 19 MrN. 4 MtN. 1 MtN. .200 U,S; ST¿NDARD SERIES*100 .50 .40'30 .16 .10'8 CLEAR SQUARË OPENIÑGS 3i8' 3t4" 't'/;' 3' 5"6" 30 20 10 0 .o74 .149 ;297 .s90 1.19 2.0 2.38 4.7ã0.42 DIAMETËR OF PARTICLE IN MILLIMETERS 25 HR. 7 HR. 45 MlN. 15 MtN. FIG.4 tr I NOTE! Q81[!..s!our.D BE Ar t-EAsr 2 tNcHEs Pg_o!y_ BoTToM oF FOOnNc Ãr ne'- lFïes_r PotNf AND SLOPE OOWmV¡nOTo A posflrvE cRAvtTy om-er-ôFi'îı A.SUMP TYHERE WATER C¡N gE --' '- REI,IOVED BI PUMPINC. B{CKN\ MIRADRAIN CzOON OR EQUIVAI."ENT ATTACH PLASTIC SHEEIING TO FOUNDATION IYATISLOPE osHA ENNRE wrDTlt PER -- CRAWL 3P¡çE J _,, FOOTTNC 0R PAD//' 'llUD SI.AB'oR WFH I OR B{RRIER f:Nctl ,Ql¡runER PERFORATED DM|N ptpE, TuEPIPE SHOULD BE PI.ACED Ñ À rNEI.iCri'iñH AllotE.gr Ar LEAsr r,/s-tNcH DRop pER FoorOF DRAIN. DAVID BROWN EROWN RE6IDENCE PROJECT NO. cso6521 .OOO-1 20 Foundation Wall Drain Goncept SIRUCruML FLOOR t+ Fls.5 TABLE ISUMMARY OF LABORATORY TESTINGPROJECT NO. cS06521.000_120ffiSILTYNO.200SIEVE41PERCENTSAND2630PERCENTGRAVEL(%\46SOLUBLESULFATÊS("/")0_00AI iERBERG LIMITSPLASTICITYINDËX(%)zCILIQUIDLIMITt%\51DRYDENSITY(PCF)MOISTURECONTENT(%)DEPTH(FEET)3-44-5IIEXPLORATORYPITTP-1TP-2Page 1 of1