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HomeMy WebLinkAbout981761.tiff GEOTECHNICAL INVESTIGATION FOR TWIN MOUNDS WATER TANK FOUNDATION LITTLE THOMPSON WATER DISTRICT for THE ENGINEERING COMPANY 2310 East Prospect Road Fort Collins, Colorado 80525 PROJECT NO. 95-028T BY SMITH GEOTECHNICAL 1225 Red Cedar Circle Suite H FORT COLLINS, COLORADO 80524 w(970)-490-2620 June, 1997 EXHIBIT ! -.-..ice._ 981761 (N Smith Geotechnical ENGINEERING CONSULTANTS June 27, 1997 Mr. Rick Pickard, P.E. The Engineering Company 2310 East Prospect Road Fort Collins, Colorado 80525 Re: LTWD Twin Mounds Water Tank Foundation Dear Mr. Pickard: Smith Geotechnical has conducted a subsurface exploration program for the referenced project. We are forwarding three copies of our report presenting the results of our exploration and testing, and our engineering review with design and construction recommendations. The opinions expressed in this report are based upon our understanding of the proposed project and the data obtained from our subsurface exploration. We have enjoyed the opportunity of working with you on this project. Please feel free to contact our office if you have any questions or require additional information. Respectfully, GEOTECHNICAL/Engineering Consultants i3;7 ' t Duane H. Smith, PE 991761 1225 Red Cedar Circle, Suite H • Fort Collins, CO 80524 • (970) 490-2620 • FAX (970) 490-2851 PERTINENT INFORMATION ABOUT YOUR GEOTECIINICAI, INVESTIGATION RET'OR'T MOST GEOTECIINICAL "FINDINGS" Many construction problems are caused by site ARE PROFESSIONAL ESTIMATES. subsurface conditions. As troublesome as Site exploration identifies actual subsurface subsurface problems can be, then frequency and conditions only at those points where samples are extent may be lessened considerably taken at the time of sampling. Data derived through sampling and subsequent laboratory The following suggestions and observations are testing is extrapolated by geotechnical engineers offered to help you reduce the geotechnical who then render an opinion about overall related delays. cost overruns and other cosily subsurface conditions. Men likely reaction w headaches that can occur during a construction proposed construction activity. and appropriate project. foundation design liven under optimal circumstances actual conditions may differ from those inferred to exist, because even the most A GEOTECHNICAL ENGINEERING qualified geotechnical engineer and the most REPORT IS BASED UPON A UNIQUE SET extensive subsurface exploration program cannot OF PROJECT SPECIFIC FACTORS. reveal what is hidden by earth and rock. The A geotechnical engineering report is based on a actual interface between materials may he far subsurface exploration plan designed to more gradual or abrupt than a report indicates. incorporate a unique set of project specific Actual conditions in areas not sampled may differ factors. These typically include: (I) the general from predictions. Nothing can be done ro nature of the structures involved, (2) the prevent the unanticipated, but steps can be taken structures' size and configuration, (3) the location to help minimize their impact. For this reason. of the structures on the site and their orientation, most experienced owners retain their (4) additional entities such as access roads, geotechnical consultants through the construction parking lots, and underground utilities, (5) and stage, to identify variances, conduct additional the level of additional risk which the client tests which may be needed, and to recommend assumed by virtue of limitations imposed upon solutions to problems encountered on site. the exploratory program. To help avoid costly problems, consult a qualified geotechnical engineer to determine how any factors which SUBSURFACE CONDITIONS CAN change subsequent to the date of the report may CHANGE. affect its recommendations. Subsurface conditions may be modified by natural or man made forces. Because a Unless your consulting geotechnical engineer geotechnical engineering report is based on indicated otherwise, your geotechnical conditions which existed at the time of the engineering report should not be used: subsurface exploration, construction decisions When the nature of the proposed should not be based on a geotechnical structure is changed; engineering report whose adequacy may hove ▪ when the size or configuration of the been affected by natural or man made forces. proposed structure is changed significantly; or • when the location or orientation of the proposed structure is modified. 991761 Speak with the geotechnical consultant to learn if review the adequacy of their plans and additional tests are advisable before construction specifications relative to geotechnical issues. starts. Construction operations at or adjacent to the site, and natural events such as floods, earthquakes, or groundwater fluctuations will BORING LOGS SHOULD NOT BE affect subsurface conditions and thus affect the SEPARATED FROM THE ENGINEERING adequacy of the geotechnical report. The REPORT. geotechnical engineer should be consulted on any final boring logs are developed by geotechnical such events to determine if additional tests are engineers based on their interpretation of their necessary. field lags and laboratory evaluation of field samples. Only final boring logs customarily are included in geotechnical reports. These loes GEOTECHNICAL SERVICES ARE should not be reproduced for inclusion in PERFORMED FOR SPECIFIC PURPOSES architectural or other drawings because drafters AND PERSONS. may commit errors or omissions in the transfer Geotechnical engineers' reports are prepared to process. Although xerox reproduction eliminates meet the specific needs of specific individual. A this problem, it does nothing to minimize the report prepared for a consulting civil engineer possibility of contractors misinterpreting the logs may not be adequate for a construction contractor during bid preparation. When this occurs. or even some other consulting civil engineer. delays, disputes, and unanticipated costs may Unless indicated otherwise, this report was result. To minimize the likelihood of boring log prepared expressly for the client involved and misinterpretation, give contractors ready access expressly for purposed indicated by the client. to the complete geotechnical engineering report Use by any other persons'for any purpose, or by prepared for the project. Those who do not the client for a different purpose, may result in provide such access may proceed under the problems. No individual other than the client mistaken impression that simply disclaiming should apply this report for its intended purpose responsibility for the accuracy of subsurface without first consulting with a qualified information always insulates them from attendant geotechnical engineer. No person should apply liability. Providing the best available information this report for any purpose other than that it was to contractors helps to prevent costly construction initially intended without first conferring with a problems which may occur. geotechnical engineer. OTHER STEPS YOU CAN TAKE TO A GEOTECHNICAL ENGINEERING REDUCE RISK. REPORT IS SUBJECT TO Your consulting geotechnical engineer will be MISINTERPRETATION. pleased to discuss other techniques which can be Costly problems can occur when other-design employed to minimize any risk. In addition, professionals develop their plans based on many engineering organizations have developed misinterpretations of a geotechnical engineering a variety of materials which may be beneficial. report. To help avoid these problems, a geotechnical engineer should be retained to work with other appropriate design professionals to explain relevant geotechnical findings and to 991.761 TABLE OF CONTENTS Executive Summary 1 A. INTRODUCTION 2 A.1 PROJECT INFORMATION 2 A.2 SCOPE OF SERVICE 2 A.3 SITE LOCATION AND DESCRIPTION 2 A.4 REPORT FORMAT 3 B. EXPLORATION RESULTS 3 B.1 SCOPE OF EXPLORATION 3 B.2 SUBSURFACE EXPLORATION PROCEDURES 3 B.3 SUBSURFACE CONDITIONS 4 B.4 GROUNDWATER DATA 4 C. ENGINEERING RECOMMENDATIONS 5 C.1 PROJECT DATA 5 C.2 DISCUSSION 5 C.3 SITE PREPARATION 5 C.4 FOUNDATION RECOMMENDATIONS 5 C.4.1 FOUNDATION TYPE 5 C.4.2 FROST AND FOUNDATION DEPTH CONSIDERATIONS 5 C.4.3 ALLOWABLE BEARING PRESSURE 6 C.5 FILL REQUIREMENTS 6 C.6 BACKFILL 6 C.7 SPECIAL CONSIDERATIONS 6 D. OBSERVATION AND TESTING 7 E. STANDARD OF CARE 7 APPENDIX A Vicinity Map Boring Location Map APPENDIX B Unified Soil Classification System Description of Terms Key to Boring Logs Boring Logs APPENDIX C Summary of Laboratory Test Data Consolidation/Swell Tests Unconfined Compressive Strength Tests Falling Head Permeability Tests x"1761 EXECUTIVE SUMMARY This subsurface exploration is for the addition of a new five-million gallon water tank at an existing tank site owned and operated by the Little Thompson Water District. The project site is overlain by surface topsoil with native vegetation. A layer of dry, silty clay lies below the topsoil and extends to depths up to 6-'h feet below the ground surface. Beneath the clay overburden soil lies weathered shale which becomes more competent with depth. Sandstone bedrock was encountered in one boring at approximately 30 feet below the surface. The clay deposit is not suitable for support of the tank foundation due to its swell potential and high consolidation characteristics. The tank must bear on the underlying shale formation which has good bearing capacity but does have a moderate to high swell potential. Some special considerations must be taken if a tank is to be constructed and operated at this site. The Owner must understand the potential risks and the design must accommodate certain precautions to provide a successful installation. The site is acceptable for the proposed construction if the recommendations of this report are followed. 1 Qo17Sl A. INTRODUCTION A.1 PROJECT INFORMATION This report summarizes the subsurface investigations, laboratory testing, conclusions, recommendations, and foundation design as prepared by SMITH GEOTECHNICAL, for the foundation of a proposed 185- foot diameter, 25-foot high, 5-million gallon water tank. This investigation is for The Engineering Company (TEC) and the Little Thompson Water District(LTWD). The site is located approximately four miles east of the town of Campion in Weld County, Colorado. The site and tank is owned and operated by LTWD for the purpose of storage and distribution of domestic drinking water. A.2 SCOPE OF SERVICE The scope of service for this subsurface exploration was limited to: 1. Advancement of four (4) borings to depths up to 30-feet below the ground surface or 5' into rock, obtaining soil samples during drilling; 2. Visual classification of soil samples obtained; 3. Laboratory testing of soil samples; 4. Analyze results of soil classifications and laboratory testing to determine foundation related recommendations, with regard to: a. general discussion of existing conditions and their impact on the proposed construction; b. allowable bearing pressure and recommended footing placement; c. requirements of fill materials and compaction of fill materials beneath construction areas; d. densification of subgrade, if required; e. frost-related design consideration; and f. groundwater and surface water considerations. A.3 SITE LOCATION AND DESCRIPTION The site is located approximately four miles east of the town of Campion in Weld County, Colorado. The site location is shown on the site vicinity map included in Appendix A of this report. The site is overlain with some native forbes and grasses and is surrounded mostly by farmland. An existing I I5-foot diameter steel tank is located on the north end of the site. The new tank is proposed to be placed directly south of 2 0p1761 the existing tank. A.4 REPORT FORMAT The purpose of this report is to present field observations and visual classification of soils, summarize laboratory results, provide engineering recommendations and foundation design. Provided in Appendix A to this report is a Site Vicinity Map showing the project site location, a Boring Location Plan showing boring locations with respect to existing and proposed feature. A set of Boring Logs showing the type and depth of soil changes and water table location is found in Appendix B. B. EXPLORATION RESULTS B.1 SCOPE OF EXPLORATION The field work conducted on May 14, 1997, consisted of drilling and sampling four(4)borings, numbered BH-1, BH-2, BH-3 and BH-4, to depths of thirty (30), twenty (20), thirty (30), and twenty (20) feet respectively below grade for the purpose of gathering area subsurface data. B.2 SUBSURFACE EXPLORATION PROCEDURES The borings were advanced with a CME-55 drill rig equipped with a four-inch diameter solid-stem flight auger. Samples were recovered from the borings for visual classification(ASTM D-2488) in the field and for future laboratory testing. Disturbed soil sampling was performed in accordance with ASTM D-1586, Standard Penetration Test (SPT). Using this procedure, a 2-inch outside diameter split-barrel sampler was driven into the soil by successive blows of a 140-pound weight falling 30 inches. After an initial set of 6 inches, the number of blows required to drive the sampler an additional 12 inches was recorded as the "penetration resistance" or "N value". The N value is an index of the relative density of cohesionless soils and the consistency of cohesive soils. A limited number of undisturbed soil samples were recovered by use of three-inch diameter thin walled Shelby Tubes pushed slowly into the soil. As the samples were obtained in the field, they were visually classified by an Engineer from SMITH GEOTECHNICAL. Representative portions of the samples were then returned to the laboratory for further examination and verification of field classification. Boring logs, indicating the depth and identification of the various strata, the N value, water level information, and pertinent information regarding the method of advancing and maintaining the drill holes, are included in Appendix B. Charts illustrating the soil classification procedure, and descriptive terminology and symbols on the Boring Logs are also included in Appendix B. 3 SF1761 B.3 SUBSURFACE CONDITIONS The subsurface conditions encountered in the borings have been used to infer the general soil conditions at the site. We assume the soil conditions between borings are fairly represented by the borings. During construction, if conditions are encountered other than those described below and as shown on the Borings Logs included in the appendix to this report, it is important that a geotechnical engineer be informed to evaluate the exposed conditions with respect to their effect on our recommendations. The following is a brief review of the various layers of soil encountered. All depths given are relative to the ground surface at the time of drilling. Please refer to the boring logs for a more complete description of soil conditions at each boring location. (1) TOPSOIL : The site is covered with approximately six (6) inches of topsoil with native grasses and deciduous shrubs growing in areas of the site. (2) CLAY: A layer of clay, which is derived from the underlying shale, extends to depths of up to 6'/-feet below the ground surface. This clay material is medium stiff to stiff, exhibited swell pressures up to 850 pounds per square foot, and is highly compressible when wetted. (3) SHALE: The shale layer begins at six(6) inches to 61-feet below the ground surface and extends to a minimum depth of 30-feet below grade. Near the surface the shale is extremely weathered. The shale becomes more competent and gains structure with depth. SPT N-values range from 13 bpf to 100 bpf. This material exhibits high swell potential with one sample exhibiting a volume change of 2.2% with a swell pressure of approximately 5,000 pounds per square foot. (4) SANDSTONE: Sandstone was encountered in BH-1 at a depth of approximately 30 feet ground surface. This material appears to be dense at indicated by the high blow count for this sample. B.4 GROUNDWATER DATA Groundwater levels should be expected to fluctuate seasonally and yearly from the groundwater readings noted on the boring logs. The time of year that the borings were drilled and the history of precipitation prior to drilling should be known when using the groundwater readings from the boring logs to extrapolate water levels at other points in time. No groundwater was encountered at the time of drilling within the boring limits. The boreholes were left open (not backfilled) so if any groundwater seeps into the borings between the time of drilling and time of construction, the groundwater level could be observed. 4 ?+?1761 C. ENGINEERING RECOMMENDATIONS C.1 PROJECT DATA The engineering recommendations made in this report are based on our understanding of the project as discussed in the following paragraphs. The recommendations are valid for a specific set of project conditions. If the characteristics of the project should change from those indicated in this section, it is important that we be informed so that we can determine whether the new conditions affect our recommendations. A proposed 185-foot diameter, 25-foot high, 5-million gallon steel water tank will be erected at the approximate location shown on the boring location plan. The tank is being purchased by LTWD to upgrade their domestic water supply to the surrounding areas. C.2 DISCUSSION The site is generally suitable for support of the new structure if the recommendations of this report are followed. The final elevation of the foundation bearing level needs to be coordinated with the depth to rock to ensure differential settlements do not take place by placing the tank partially on overburden clay. C.3 SITE PREPARATION The site should be stripped of any topsoil and grasses prior to any work being conducted. The clay soil overlying the site is very dry, is highly compressible, and swells when saturated. This material should not be utilized as support for the tank but should be removed. The shale formation on site underlying the clay has a moderate to high potential for swell if saturated and care must be taken to ensure this layer does not become saturated. Drains in conjunction with positive slope away from the foundation should be employed to prevent saturation of the shale. Leaks from the tank must be directed away from the subgrade to prevent saturation. C.4 FOUNDATION RECOMMENDATIONS C.4.1 Foundation Tvtlg A ring wall foundation is recommended for this structure bearing on the shale formation or on a compacted subgrade. The foundation should bear on the shale only if precautions are taken to ensure any tank or water line leakage can be controlled to direct the water away from the tank without saturation of the subgrade. This may require under drains for the tank or consideration of sealing the surface under the tank to prohibit saturation in case of a leak. The water lines into the site must be designed to prevent water from a leak running to the foundation area and saturating the tank foundation area. C.4.2 Frost and Foundation Depth Considerations The tank foundation should be placed at least 36-inches below the final exterior grade to provide proper protection from frost damage. Due to the variation in grade and depth to rock over the site, the final tank elevation needs to be set to ensure the foundation does not sit on some overburden clay and some shale. 5 1:!.C. 1.761 C.4.3 Allowable Bearing Pressure For a ring wall type foundation bearing on the weathered shale, the foundation may be designed for a maximum bearing pressure of 3,500 pounds per square foot (dead plus live loads). The footing should be designed by a competent structural engineer and all load conditions taken into account to ensure the ring stresses and bearing pressures are not exceeded. The total settlement for this loading is not expected to exceed I-inch beneath the ring wall foundation. Settlements at the center of the tank will depend on the type of backfill utilized. If a pit run type material is utilized, total settlements less than 1-inch would be expected at the tank center. Differential settlements should be addressed by the foundation designer for the different load conditions, especially wind loads, to ensure these are not a problem. If a clay type material is used for the backfill, consolidation tests would need to be run to determine the settlement expected. C.5 FILL REQUIREMENTS It is recommended that a CDOT class 6 road base or a pit run material with at least 12% fines be used as fill beneath the ring foundation if required and beneath the steel tank within the ringwall. This fill should be placed in nearly level lifts, not more than 8-inches loose thickness. Each lift must be compacted to a minimum of 98% of the maximum thy density as determined by a standard proctor test (ASTM D698), at ±2% of the optimum moisture content. The existing clay may be suitable for fill if removed, moisture conditioned, and compacted to 98% of ASTM D698. This would require additional testing to determine if the soil is suitable for fill when compacted. It is not recommended that any of the existing onsite clay materials be utilized as backfill beneath the tank foundation or beneath the tank shell unless additional testing is conducted. The clay material may be utilized as backfill on the tank exterior. All fills that will support structures or slabs should be tested by a geotechnical engineer to assure adequate and uniform density is obtained. For no reason shall the new tank foundation rest upon any fill material which is not designed and tested by a geotechnical engineer. C.6 BACICFILL Backfrll around any onsite structures may utilize the existing site materials and should be placed to at least 95% of the maximum dry density determined by a standard proctor test at ±2% of optimum moisture. Where the backfill will support a structure or concrete slab, we recommend removing the overburden clay and replacing with non-expansive soil or pit run type fill compacted to at least 98% of the maximum dry density determined by a standard proctor test (ASTM 11698) at ±2% of optimum moisture. C.7 SPECIAL CONSIDERATIONS The existing onsite clays have a swell potential of approximately 850 psf in their natural state when saturated. These soils are relatively dry with natural moisture contents of 10% and saturated moisture contents of approximately 20%. These soils also exhibit high consolidation characteristics when saturated. It is not recommended that these soils be used as subgrade support for the tank shell. 6 ?'?1761 The shales on site have a high bearing capacity but do have moderate to high swell potential. Some of the shale samples tested indicated no swelling when wetted, however, one sample tested swelled 2.2% with a swell pressure of approximately 5,000 psf. The shale is interbedded with sandstone and some of the shale does not swell due to its cementation and high sand content. There is enough potential however to require special precautions be taken. These include consideration of an under drain to ensure the subgrade does not become saturated if the tank leaks, a minimum 2%positive slope away from the tank so water can not stand around the tank, and consideration to sealing the tank subgrade to minimize any leakage from saturating the subgrade. Steps should also be taken to ensure water from a pipe leak can not drain into the foundation area thereby saturating the tank foundation bearing materials. There is a tank onsite that has been in place for many years that has not experienced problems due to swelling soils. This indicates that this site can be utilized with some precautions to ensure the subgrade does not become saturated. The tanks are on top of a hill such that runoff and fluctuations of groundwater would not be expected to be a problem. The greatest risk is from a tank leak or from a waterline leak. Both of these leaks can be controlled somewhat with some minor design consideration. If the considerations and recommendations in this report are followed, we see no reason why a tank should not be successfully located and operated on this site. There is some risk however, with the swelling soils, that the Owner must address and accept if a tank is to be located on this site. Leaks need to be detected quickly and repaired quickly and the Owner must be aware of this. D. OBSERVATION AND TESTING Since a project of this nature requires many soil related judgements and decisions, we recommend that an experienced geotechnical engineer be retained as part of the construction team. We strongly recommend that all footing trenches be visually inspected by a geotechnical engineer or trained technician prior to placing concrete. Any unsuitable or wet soil conditions existing at footing level can then be delineated for removal and replacement. We also recommend that a limited number of compaction test (approximately one test for every 100 cubic yards of fill placed) be performed to document the degree of compaction obtained in backfill and structural fill. SMITH GEOTECHNICAL is equipped for, and would be pleased to provide, the recommended quality assurance testing of concrete and construction fills for the proposed project. E. STANDARD OF CARE The recommendations contained in this report represent our professional opinions. These opinions were arrived at in accordance with currently accepted engineering procedures at this time and location. Other than this, no warranty, either expressed or implied, is intended. - taamttnre ftl% — Prepared and sub Vit fi.c49 S1-TIC GEOT 4{ Y/ ing Consultants (..._______</ •p j¢r v. k,- Duane H. Smitli� i .�����N������T�z oii�m�NAI.P�u�`� 7 9! i 761 APPENDIX A Vicinity Map Boring Location Map $`?1761 N PO u O .I 1 is t ; i v .xrenKm [ CIASSICAOS sot el At so;X 'S J�u5111111'J • ,.Y It 5•' 7/ tm ma �� l_ \ V r 11 C:, t.N� •tVl% R' (�, 1 I�VS n I1 1;E .door \r ( k•..19L �1 k:.4,V ., gal lak� N)0 • L 11111111 lu1 It 11 ' J IIIIIIIIVI t Ir/@ _� Coal /cr` II :I I"= / .J-9 ¢lend V '2365 3,..1� ,. •• ` g d .' .m. 1 ii. I. , 1.....m ,K.O -..�— , .1'. (g < -.A. . wr. KC;ON V( , tae i`::�`il `• st R ViVT lands _J }. � g9csr�l na u. �ybm i .CJ '!: .1 ''LICLw •-SWA /'e IS!SI l g 1Kfl,c A 5wn'� { �..-. Simuwn Ponds ' i-� ..b 402 blb..n SWA _ _J. G InxM J ]r 1., fl p.. Cww. i.e.' , QI .. flY 10 L 0221 g1:Hi6'ICr.� _ M w n w Na- Tt.9,. •q.WA g xw RnerOd n b , L. p C�uv+.., O i • BB ° SITE , m I ,.. so ' tone Tree a-. ••"I. u• c. r..., 25 Reservoir w�` i .. Q M("'"( e • 287 S 87 21 //11�� Ih&owe• yw —)Rr.a.uoi. - El.rl aftl' �F,'L' Berthoud t p w' g.K a no Re✓rua MI Iwo, 68 -"7 • Rn.no' S...nvrkNK O _ :U _I Br-rerun. W.��,,y wx4. _ _ igloo ac I&J. YMO.... Welch Ilo,...W 2 Resew°. I .Al v I M AO Rcten..r 0 b nw to AO Ww I G r. 1 ��bnu.n� fNttn t I Lgaq. _' OkO 7 ® _ - �d Berthoud 56 C ,o ?kn.:. y P /N•nxm.p t.41 1 N...-.... (I .1 • F \1 Deck 9..1,4 4� K w ,- f V n b 2l Q.s 0!O V J )w _ _.. .1____. w'r } __ g nI? 22 ;2 _l ''- K \%1 -._D k< god _ DIAL('1 b V 0J Lake l_• .3 Rockwell Oa.. '— I Litt . P $ $ Re, 1 9 Rn�o • / II I'e Z to ' c • Qi) 'Blue M.n . ,g w I 5 . T RC+<n.o-. c '. Rao a _F t: • Rc.rmO'ICo I — / \ O µiyLlnnn v OPS ` • �/� Iy k,.11— iRtherow I�,n i .p L.E• 1I --- I = n2- lOw4.d1'Co .l.lO�f.O+[ O - M•u'' yN 09., w/ eO 0.rOON v _. �\ I nl. b y _ —T, .4OIw . P.,,,..,. F t,wn / rl I .-\ LITTLE THOMPSON WATER DISTRICT TWIN MOUNDS TANK C�smltIn � Cootecnnical SITE VICINITY MAP ENGINEERING CONSULTANTS 49"1 761 EXISTING TANK 60' L BH-1 p BH-2 PROPOSED TANK 71 .5° O BH-3 O BH-4 LITTLE THOMPSON WATER DISTRICT TWIN MOUNDS TANK ISC ces le Ite Sotechnlcal BORING LOCATION PLAN ENGINEERING CONSULTANTS St1761 APPENDIX B Unified Soil Classification System Description of Terms Key to Boring Logs Boring Logs 9'1761 Unified Soil Classification till s Ideroicai on ProccEuru Group I Information Required for Laboratory ClaaiAcatlos (Earl wrong peal„clu urger than J in.and barmy fractions or Symbmslt Typical Names Describing criteria • uiJnaled weight') • r I Wide ranee in gran vibe and mbuanita] Well graded gravels. gravel. Co ••• D1p Orca Le that 4 mounts of au in:ermedirte particle Cay sand :alum. little or no .� `o D1° a o c i - I lists on, Dive typical name: indicate ap- a 2 Crogo Bolween 1 and J o a' d ^ Pmaimue percentages of sand c 2 ; C Dt° x D1° _- Y _ and onset: maximum Hu: aPlcOOm,naniiy one siren a <of rnas I I Poorly traded erasels, gravel- angulari) surface condition. + — d _ r nn: LP > 0 Not matins all gradation requirements for Lu' y re n tan ea ic e sites missing sand n , ores. le or names and hardness of the e se E y ti -- — - -- grains. lo<ai or geologic iileac name P • • p' r lee J[n I[, O+ pro- Silty gratis. poorly graa[d and O n<r Berl I due Alive -tali Y Attar Oerg limits below Above 'A' ten eZ -- eJu.o,<c NI olio» G ! va•a•and , m, tare, nfor mat bra and s>'m Holt in _yy A' Inc or P/ leg w th PI between • 22 - parentheses c -. -X:: than, a and ) as d E` -••: %auc[nn(for AenuOuupn procedures, GC Claye grate's. poorly graded For undisturbed soils add informs - V.^.yy rr Atlerbelg limit' •bo•c pauifing e of e, $ eZ IUe . sea Cl,below) ! pro.<han lion on stratification.degree Of `env V�� "A"line.with// requiring use of d•day miatorea - gross dual symbols • C2 s' c compactness, cementation, CO <] greater than) - moisture conditions arid 2 Ot • Fy 2 ° - wmc rantt m train sites and suesumml Well graded unas. tn+nly drainage characteristics ... `o V V m Cp Doi? Greater than 6 amounn of all intermediate particle SW • C e o : ; - s'ut sands,little or nO Ones Example C.. C C (Dada Between I and 3 o - _ <- Sillyhardnd.gulaclly: about 20: »ss N C_ Otg x Daa') u- t' •< hard,angular gravel particles o C oar. "o=• St- - � a Picadminan'ir one site or a ante of sus Poorly graded sands. gra•ell5• I•in,maximum size: rounded o �.U+n ' - _ »gym some .nic.mcd um sizes missing SP sands,tu::e or no M<s ] and subanvubr and trains x open Not mating all tradition regultemrnu for SW coarse todneabout 15',,non. c- dnp tat c ._, (for pro- Spf Silts sands.pooh) graded sand• P s T fines roll low dry tit c -u? Autsb<ra limits Oelov Above "A" fiat • «guru.se[ lL um.l , m,rot's • Strength. II compassed and E t°e u w oS A line or Men INa wills P/ belwae =2 - � moist in place. alluvial and: wd.Zn 5 4 and ) a L$ 4C - (She) o Borderline uses - Sr = n' t P.ae <nn<+(foi sands red d .VO" Attesters I:m,i Wow .- .urn. .c,.�O Oc<r.w.+ C.aa[0goo t e - "A" lane with PI rquinog use or c • SC ""3 "1 dust symbols _—. c gums than] Dry Soenglni Tougnnen . c D�acancr t y C 60 tar wnma (comas[ c troc(,on - Stijl d n ac [ vvmv) plastic 'a " sal l C Compuint Will al stied liquid limit 50 s _ Inorganic + t and very M1ne - l f M I I 0 <c m d rock flour. S a or Giro typical name dba<d tea - u $ < N n< AILy and character of plasticity. a 40,=lautnnw sM do salt'oil kiuuu ' suit, sin» Clayey fine sands ""b 'I'll" a u cif mourn and maximum sine of =:M"notation plasticity Wu p t'1' y coarse n,oil colour in rots >. a Z E__ Inorganic clays or low to condai n,odour it any,local or 'V 30 None Io pledrum CL medium plasocdy. gravelly geologic name,and other pert.- : _ '- - f • tier. very slo- Tian.handy clan.silly clay,. anaa«lien:ve information, q 20 OH I Si -- '.i li Urvan e tint and organic vita symbol n pa<nthcsea s tt w • B.d_ Stitt.; curt tan of o-pt'+ c tr For undisturbed sods add infor. x 10=CI w� tax it' < notion on structure stratlfca• -1 -t-kt x( WE Inorganic silts. micaceous or .a ' Sio» t maven m ' Ain diatomaceous M1ne sans of ;ion emould d in o undisturbed 00 10 20 30 40 50 60 70 80 90 100 - medium none o meamm ICI vlty soils,easuc file Y and remoulded d solo,moisture L - and drainage conditions `2' -_ H,gn iO • Inorganic clays of high plan. Liquid limit nnn none High CH 9 - •cry uClty,fu Clay Examylr. /t I Medium Io ' None to Slight to Organic<lays of medium to high CloyeY silt, brown: slightly Plasticity chart y c^ highvery slow medium On tactual. plastic: small tale of - pfor laboratory classification of fine grained soils M1ne sand: numerous vertical Readily 'denoted by colour- odour. Peat and Other highly organic root holes: Arm and dry in Highly Organic Soils sporV!cut:reel and frequently by Obrous Pe soils place:los: (AFL) lulus° From Wagner,195], • Boundary elasufrdaonx. Soils possessing chan<teristi<r of two groups arc designated by combinations of group symbols. For example ew-CC,well graded travel-and mixture with clay binder. 5 All sieve sixes on'.Six chart are U.S.wnCard. Field Idrnitfirclion Pras'In ure for Fine Crainrd Soils Or Prarlionl TTeae proud,rte arc to be performed on the minus,So.40 sieve Sae particles,approximately kit in. For field classldca lion purposes,screening in not intended,simply remove by hand the coarse particles teat interfere with the testa. Dilnl<nry(Reaction to inning) Dry Steen:in(Crush:ne characteristics): Toughness(Consistency near plastic limit): Alter removing Panicles server Irian NO. 40 ticie Sire. prepare a pat of Afln re monina particles larger than No.40 sieve siu,mould s pat of soil After removing particles larger than;be No.40 sieve sit,a specimen of rnoiaI soil with a volume of aboa.t one•naif cubic inch. Add cnou¢n IC the consnleney of putt,adding water if necessary. Allow the par to soil about one.halr inch cube in size,Is moulded to the consistency of /j0 .ater if neury It'rake the Soil soft Out nol unity dry completely by on,sun or air drying,and then teal Its Strength by putty. If too dry, water most be added and If sticky, the specimen :.� Pau the w pat the open p of one nand and snake hontoniat,sinking breaking and crumbling between lame the Posers. This strength is a measure should be spread out in a thin layer and allowed to lose moisture v,vo rousn deans ine :Inc:c. A positive it acnon of lie chancier and goan"Iy of the colloidal fraction contained in the by evaporation. Then the specimen is rolled out by hand 00 a amootb c s l ppc f - ire pa - n + : . nincreasing plat ctiy surf¢' or between the palms into a .Mad about one-eight Inch to :tsarina 'a I,: [rev s: loi clays o' n[ CII group A typical diameter The thread is then folded and re.roll°d repeatedly. During .1/441 1..ttast po very slight dry strength. Silty fine sands thismman-pulation Inc moisture content is gradually reduced dad the CI P- a o a d,:n errs 'rne n but tan sects ngu shed specimen stiffens, finally totes lea plasticity, and crumble, weed we V• :. g c p e cal win , p n ee n[ dried specimen Fins urea fens gritty plastic limit Is reached. v c y '+ a cn as cal t + of n feel or flour. Af e+ rte thread crumbles the pieces should be lumped together and a ilia . y c v 4 d, c tllht kneading action eomtu recd until the lump crumbles. a pa.c pant l.. a gyp o r(x. The tougher the thread near the plastic limit and the stiffer the lump when .'a.:.ino»•a rr.oee aI0U Xi-it. r<aumn it[malty crumbles.the more potent Is the colloidal clay fraction to the soil. Weakness of the I reread It the plastic limit and quiet Ims of coherence or the lump below the plastic limit Indicate either moreanld clay of low plasticity.or materials such as kaolm•type clays and Ortaoic clays which occur below the Arline. STIFFNESS/RELATIVE DENSITIES OF SOILS BASED ON SPT N-VALUES CLAYEY SOILS I ( SANDY SOILS �LATIVE 1 I UNCONFINED N LCONSISTENCY COMPRESSIVE N DESCRIPTION DENSISTY STRENGTH(psO 2 Very Soft 500 <4 Very Loose <0.2 2-4 Soft 500-1000 4-10 Loose 0.2 -0.4 4-8 Medium Soft 1000-2000 10-30 Medium Dense 0.4 -0.6 8-15 Stiff 2000-4000 30-50 Dense 0.6-0.8 15-30 Very Stiff 4000-8000 > 50 Very Dense 0.8 - 1.0 > 30 Hard 8000-16000 DESCRIPTION OF ROCK HARDNESS Very Hard- Cannot be scratched with knife or sharp pick. Breaking of hand specimens requires several hard blows of geologists pick. Hard- Can be scratched with knife or pick only with difficulty. Hard blow of hammer required to detach hand specimen. Moderately Hard- Can be scratched with knife or pick. Gouges or grooves to 1/2 inch deep can be excavated by hard blow of point of geologists pick. Hand specimens can be detached by a moderate blow. Medium- Can be grooved or gouged 1/16 inch deep by firm pressure on knife or pick point. Can be excavated in small chips to pieces about one inch maximum size by hard blows of the point of a geologist's pick. Soft- Can be gouged or grooved readily with knife or pick point. Can be excavated in chips to pieces several inches in size by moderate blows of a pick point. Small thin pieces can be broken by finger pressure. Very soft- Can be carved with a knife. Can be excavated readily with point of pick. Pieces an inch or more in thickness can be broken by finger pressure. Can be scratched readily by fingernail. DESCRIPTION OF ROCK WEATHERING Fresh- Rock fresh, crystals bright, a few joints may show slight staining. Very slight- Rock generally fresh, joints stained, some joints may show clay if open, crystals in broken face show bright. Slight- Rock generally fresh- joints stained and discoloration extends into rock up to one inch. Open joints contain clay. Moderate- Significant portions of rock show discoloration and weathering effects, shows significant loss of strength as compared with fresh rock. Moderately severe- All rock except quartz discolored or stained. Rock shows severe loss of strength and can be excavated with a geologists pick. Severe- All rock except quartz discolored or stained. Rock "fabric' clear and evident but reduced in strength to strong soil. Some fragments of strong rock usually left. Very severe- All rock except quartz discolored or stained. Rock fabric discernible but mass effectively reduced to soil with only fragments of strong rock remaining. Complete- Rock reduced to 'soil'. Rock 'fabric' not discernible or discernible only in small scattered locations. Quartz may be present as dikes or stringers. 99.1761 KEY TO BORING LOGS soil and Rock Samplers Iilr—III- ® California II—dII—_i TOPSOIL III III Split Barrel J , f . FILL — rr .r r . , Shelby Tube ' " SILT 0 Bag/Auger Cuttings a CLAY 0 SAND Symbols LWIDP=: = '"� GRAVEL V ,n....•. . Water Table ------ SHALE & CLAYSTONE Definite boundary -- -- — _ _ _ Indefinite boundary SANDSTONE •... . ... ►........4 ►���������4 BEDROCK rn Smith Gootochnlcal ENGINEERING CONSULTANTS 9"1761 BORING LOG SMITH GEOTECHNICAL ENGINEERING CONSULTANTS BORING NO. 8H-1 PROJECT JOB NO. SHEET OF TWIN MOUNDS TANK (Little Thompson) 97.028T 1 1 CLIENT FIELD ENGINEER THE ENGINEERING COMPANY 11 DRILLING COMPANY DRILL RIG DRILLING ENGINEERS CME 55 w/4"0 OD FLIGHT AUGER LOCATION ELEVATION DATE 5172.61 MAY 14, 1997 DEPTH LOG DESCRIPTION OF MATERIAL BLOWS/6 IN. REC REMARKS (FEET) INCREMENTS -- (PER FOOT) J,,// � CLAY; brown, silty, dry, medium 4-2-6 // // hard (8) i -- r SHALE; brown & gray, dry, iron 6-6-8 5 =----` stained, severely weathered, soft (14) _ __ SHALE; same 10-12-17 to— (27) r -4 ISHALE; same, sandy 12-14-20 is---- (32) NO G.W. i 20--- _i SHALE; same, sandy, damp 9—115>23 32TISHALE; same, sandy, damp 10-14-20 25- (30) - SHALE; brown, damp, sandy, some 12-50-50 — iron staining, soft (100) 30- red—brown, dry, fine EOH 30' \ grained, severely weathered, soft ------------ 'i5 9"1761 BORING LOG SMITH GEOTECHNICAL ENGINEERING CONSULTANTS BORING NO. BH-2 PROJECT JOB NO. SHEET OF TWIN MOUNDS TANK (Little Thompson) 97.028T 1 1 CLIENT FIELD ENGINEER THE ENGINEERING COMPANY TT DRILLING COMPANY DRILL RIG DRILLING ENGINEERS CME 55 w/4"0 OD FLIGHT AUGER LOCATION ELEVATION DATE 5172.14 MAY 14, 1997 DEPTH LOG DESCRIPTION OF MATERIAL BLOWS/6 IN. REC REMARKS (FEET) INCREMENTS r, (PER FOOT) ����/r CLAY; brown, silty, dry, medium 5-3-5 �J//// plastic, medium hard 10 ----T SHALE; gray, brown, orange mottled 7-7-10 5 �.L dry, iron stained, very severely (17) —t____ weathered, soft __- _____ SHALE; some, sandy 10-20-20 (30) 10m__ NO G.W. 15---- -____ SHALE; brown & gray, less sand, 12-14-15 less iron stained, damp (27) SHALE ra brown, moist, severely -{ I weathered &, iron stained, soft 12-18-24(36) EOH 20' 20 25- 30 is •49 F1761 BORING LOG SMITH GEOTECHNICAL ENGINEERING CONSULTANTS BORING NO. BH-3 PROJECT JOB NO. SHEET OF TWIN MOUNDS TANK (Little Thompson) 97.028T 1 1 CLIENT FIELD ENGINEER THE ENGINEERING COMPANY TT DRILLING COMPANY DRILL RIG DRILLING ENGINEERS CME 55 w/4"0 OD FLIGHT AUGER LOCATION ELEVATION DATE 5169.09 MAY 14, 1997 DEPTH LOG DESCRIPTION OF MATERIAL BLOWS/6 IN. REC REMARKS (FEET) INCREMENTS (PER FOOT) jCLAY; light brown, silty, stiff, dry, 6-7-8 medium plastic (15) CLAY; brown, silty, dry, stiff, w/some 6-5-4 ) 5 grav l/shale fragments, medium 9 plastic _ SHALE; brown, dry, soft, severely 9-25-28 to weathered, w/iron stains (53) NO G.W. SHALE; brown, gray, orange mottled, 15 damp, soft, sandy, severely ir on ron stained 13-12-18 (32) SHALE; gray, moist, soft, some sand 12-18-24 20-� I iron stained, severely weathered (42) SHALE; brown & gray, moist, iron 20-25-37 25— stained, severely weathered (62) SHALE; some 15-15-29 1 (44) EOH 30' 30 991761 BORING LOG SMITH GEOTECHNICAL ENGINEERING CONSULTANTS BORING NO. BH-4 PROJECT JOB NO. SHEET OF TWIN MOUNDS TANK (Little Thompson) 97.028T 1 1 CLIENT FIELD ENGINEER THE ENGINEERING COMPANY TT DRILLING COMPANY DRILL RIG DRILLING ENGINEERS CME 55 w/4"0 OD FLIGHT AUGER LOCATION ELEVATION DATE 5168.47 MAY 14, 1997 DEPTH LOG DESCRIPTION OF MATERIAL BLOWS/6 IN. REC REMARKS (FEET) INCREMENTS (PER FOOT) syCLAY; brown, silty, dry, medium soft 2-2-4 medium plastic (6) =I SHALEbrown, dry, sandy, w/some 8-7-6 5 calcite, soft, severely weathered (13) --- — —_SHALE; brown & orange, damp, soft. 1 10— sandy, severely weathered 8-12-15 NO G.W. (27) - SHALE; gray, moist, sandy, soft, 11-17-25 1s---- severely weathered (42) ---r' SHALE; some, trace sand 15-20-26 EOH 20' — (46) 20 25 30 75 ?"1761 APPENDIX C Summary of Laboratory Test Data Consolidation/Swell Tests Unconfined Compressive Strength Tests Falling Head Permeability Tests FF1761 SUMMARY OF LABORATORY TEST DATA SMITH GEOTECHNICAL Project: Twin Mounds Tan 97.028T Dare: 16-May-97 HOLE SAMPLE TYPE t NUMBER DEPTH OF MOISTURE DRY ATTERBERG'S PASSING UNCONFINED CONSOLIDATION/ PERMEABILITY SAMPLE CONTENT DENSITY LL/PL #200 SIEVE COMPRESSION SWELL (feet) (%) (pcf) (%) (%) (cm/sec) [attached] [attached] [attached] BH-1 .5-2 SS 10.1% 104 BH-1 3.5-5 SS 13.3% _ 98 _ J x X BH-1 8.5-10 SS - BH-1 13.5-15 SS 19.1% BH-1 18.5-20 SS 17.6% BH-1 23.5-25 SS BH-1 28.5-30 SS - BH-2 .5-2 SS BH-2 3.5-5 SS BH-2 8.5-10 SS 14.2% BH-2 14-15 ST BH-2 15-16.5 _ SS BH-2 18.5-20 SS 18.7% BH-3 .5-2 SS 9.5% _ 99 39 / 18 X BH-3 3.5-5 SS 7.6% 119 - BH-3 8.5-10 SS 12.8% 112 X X X BH-3 f 14-15 ST 18.2% 117 BH-3 15-16.5 SS BH-3 18.5-20 SS - BH-3 23.5-25 SS 16.9% e, BH-3 28.5-30 SS "a BH-4 .5-2 SS 12.5% 47/ 15 :J - *41/41 BH-4 3.5-5 SS T BH-4 9-10 ST 19.9% X N BH-4 10-11.5 SS • BH-4 13.5-15 SS BH-4 18.5-20 _ SS 17.5% i CONSOLIDATION/SWELL TEST ASTM D4546 TWIN MOUNDS TANK BH-1 @ 3.5' - 5.0' REMOLDED 1 .0 I I J 0.5 J ' W (/) 0.0 • • , I C-0.5 -I ` I , i -1 .0 { j IIII I O I • Q -1 .5 - . _ . , O J O2 -2.0 _ Z 1 1 E O (.) -2.5 . i -3.0 ' _ _ ,, i 10 100 1000 10000 : 1 I APPLIED LOAD (psf) N 1) i CONSOLIDATION/SWELL TEST ASTM D4546 TWIN MOUNDS TANK BH-1 3.5'-5.0' REMOLDED 0.72 - , 0.71IIII_ - - 0.7a - — -------------- - ' ”'' ”'Illim a 0.69 Ob 1 1` 0.68 - . >j 0.67 . . . � . - , , , 0.66 { . _ - �` 1 . I.1 0.65 r . . P, 0.64 _, _ - , , . . . 10 100 1000 10000 APPLIED LOAD (psf) NI 01) F+ CONSOLIDATION/SWELL TEST ASTM D4546 TWIN MOUNDS TANK BH-3@3.5'-5.0' REMOLDED 5.0 4.0 3.0 w g 2.0 - 1 .0 i - - I O 0.0 • -1 .0 z O -2.0 - F o -3.0 - - Oo -4.0 — - - z O -5.0 U -6.0 7.0 . 10 100 1000 10000 .' APPLIED LOAD (psf) ski CONSOLIDATION/SWELL TEST ASTM D4546 TWIN MOUNDS TANK BH-3@3.5'-5.0' REMOLDED 0.84 j 0.82 _ _ _ i 0.80 , ' ' 1 00.78 I ! 1 - I , - \'---O0.76 - _ . 0.74 - . ___\. l 0.72 _ �,_ - _ , 1 0.70 I I I i , 10 100 1000 10000 APPLIED LOAD (psf) • N CONSOLIDATION/SWELL TEST ASTM D4546 TWIN MOUNDS TANK BH-3@13.5-15.0' 5.0 4.0 - - - 3.0 - - - - w I 0) 2.0 - - 1 .0 I S 0.0 -1 .0 - - _ . z O -2.0 j _ . - o -3.0 -- - - - O� -4.0 - - z O -5.0 - — -6.0 -t- I -7.0 - 10 100 1000 10000 Ah APPLIED LOAD (psf) N CONSOLIDATION/SWELL TEST ASTM D4546 TWIN MOUNDS TANK BH-3@13.5'-15.0' 1 0.410 r I , ' , IF-- - ,_____ _i - , , . 0.405 - ----- i 0.400 - 1 O 0.395 Q , Iki , . j 0.390 - O 0.385 1 I 0.3$0 I I 1 0.375 . _ . '.0 10 100 1000 10000 Ai i APPLIED LOAD (psf) 74 . CONSOLIDATION/SWELL TEST ASTM D4546 TWIN MOUNDS BH-4@8.0'-10.0' ; • -- - 1 ' -- - ---1- ' -I -1 -- --i.._- 4 41_ ili _ 1 - - r r I I u) ► I w p _._._�. I I i 2 I f I I i _ ,l ■ \I I I . ' - -- -- ' _ �._._..... ..�-- ---i- . . !_ _: , ..- -1-----3 -- . r ; _____ ' i 1 -4 ; 1 _ 1 I _ 10 100 1000 10000 a) I PRESSURE (PSF) 1-+ CONSOLIDATION/SWELL TEST ASTM D4546 TWIN MOUNDS BH-4@8.0'-10.0' I • — . . I I H. - ---- - - - • I. . i 1 I • :•• . 0.65 --- -- ---+--,---I---- _+_ -! I Ii I - ------- -- -i-I i - - j ! ! { ! f ! I Q 0.6 `..__..-._.:_ ...._...'....�.-- .. -..-.._..---- -+ ' �- ----._- ---I--- ' } • - -_ • I i o ---- --- -- ---+-- I - > i . : , o 55 -- --_I__ ! 1 I _i_...-- __,-- - -- - I i .i..... i - --- ----_ - 1 : I � i I 1 i it 0.5 10.000 100.000 1000.000 10000.000 A APPLIED LOAD (psf) M _. ---- _.J UNCONFINED COMPRESSIVE STRENGTH TWIN MOUNDS BH-1 @13.5'-15' ASTM D2166 3500 I I 3000 '-` . 2500 ; - i a 2000 ------ /7 - c cip I W H 1500 - v) 1000 i I 500 —' !4 0 a 0.0 0.5 1.0 1.5 2.0 2.5 CI STRAIN (%) TWIN MOUNDS TANK BH-1 3.5-51k FALLING HEAD PERMEABILITY TEST Remolded sample w=18.2% DD=127pcf 1.0E-04 - ----- --- -- - _------ - - - - - - ---- U U h E U 1 .0E 05 - - 1 ¢ ---1- U.) a 1.0E-06 02:45 PM 02:59 PM 03:13 PM :1 JUNE 2 1997 (TIME) T TWIN MOUNDS TANK BH-3 13-15ft j FALLING HEAD PERMEABILITY TEST Remolded sample w=18.2% DD=127pcf 1 .0E-04 U N N a 1.0E-05 r Li _4 - — — w —T -r a to 1 .0E-06 4.. - r -J A 02:30 PM 02:44 PM 02:58 PM 03:13 PM 03:27 PM 03:42 PM 03:56 PM NI JUNE 2 1997 (TIME) a) N i Hello