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DR9503-SY 951226 BuFke ~ Thompson Engineering Consultants .' GEOTECHNICAL INVESTIGATION ANDREW BROWN JR. COMMUNITY PARK OUTFALL STRUCTURE COPPELL, TEXAS Patton, Burke and Thompson INVOICE 10555 Newkirk Street, Suite 530 Dallas, Texas 75220 I I 12/29/95 95-292 BILL TO: City of Coppell 255 Parkway Blvd. P. O. Box 478 Coppell, Iexas 75019 Attn: Mr. Kenneth M. Griffin DESCRIPTION AIVIOUNT Geotechnical Consulting Services Andrew Brown Park Outfall Structure PBT Job. No. 101-003 Period Covered: Through December 29, 1995 Field Services Drilling Services $430.00 Field Engineer 4 hrs x $45/hr 180.00 Laboratory Services Moisture Content 8 x $5/ea 40.00 Unit Weight 4 x $10/ea 40.00 Atterberg Limits 4 x $35/ea 140.00 -No. 200 Sieve 4 x $20/ea 80.00 Engineering & Report Preparation Principal 5 hrs x $95/hr 475.00 Drafting/Word Processing 3 hrs x $35 105.00 $1,490.00 COST NOT TO EXCEED $1,000.00 This invoice, prepared on 1/3/96, is due and payable upon presentation. TOTAL $1,000.00 December 26, 1995 10555 llewki~k Street ._ Suite 530 Dallas. Texas 75220 214.831 .1 1 I ! FAX 214.831.0800 -- City of Coppell 255 Parkway Blvd. P.O. Box 478 Coppel]. Texas 75019 Attn' Mr Kenneth M. Griffin, P.E. Assistant City Manager Git5· Engineer Re GEOTECHNICAL lh~,'ESTIGATION ,\nd:'ex~ Brown Jr Communiw Park Outfall Structure _ Coppell, Texas PBT Job No. 101-003 - Dear Mr Grifl~.n Pa:ton, Burke & Thompson (PBT) has completed the geotechnical engineering study for the above -- retb:-c~'~ced lX'(\iect, and hereby subnfits three (3) copies of our report. The assignment was carried out in general accorda::ce w!:!: our discuss:,ons and site visit on November 30, 1995. -- ()ur firm appreciates the oppo:'tunity to be ofcominued professional sen'ice to the City ofCoppell. \Ve would be pleased to discuss any questions which may arise concerning this report. If we can be of further assistance, el:her in regard to final design or construction inspection and testing actMties, please call. Respectively submi:ted, I~;VI'TON, BL'RKI-7 & TIIOMPSON ___ Principal Petton, Burke & Thompson Engineering Consultants TABLE OF CONTENTS _ Title Page 1.0 SCOPE .................................................................. 1 2.0 SUMMARY OF CONCLUSIONS ............................................. 1 .3.0 SITE CONDITIONS ....................................................... 1 4.0 PROPOSED REMEDIATION ................................................ 2 5.0 FIEI_D AND LABORATORY INVESTIGATIONS ................................ 2 6.0 SUBSURFACE CONDITIONS ............................................... 3 - 7.0 DESIGN RECOMMENDATIONS ............................................. 4 7.1 Outfall Structure Foundations .......................................... 5 _._ 7.2 Creekside Slope Stability . ............................................. 6 8.0 DESIGN REVIE\V ......................................................... 7 9.0 LIMITATIONS ........................................................... 7 FIGURES Boring l_ocation Plan ................................................... Figure No. 1 Boring Logs ................................................... Figures No. 2A & 2B - T['iaxlal Compression Test ................................................ Table No. 1 Pa*ion, Burke ~ Thompson 1.o SCOPE __ This report presents the results of a Geotechnical Investigation of an existing outfall structure located in the Andrew Brown Jr. Community Park in Coppell, Texas (see Vicinity Map on Fig. 1). Our investigation ,,','as ._ conducted to evaluate subsurface conditions and provide foundation design criteria for repair of the existing structure. Currently, the existing structure has experienced significant distress, at the discharge point to Denton - Creek. apparently caused by erosion of the creek bank and undermining of the outfall structure footing. The investigation was completed in accordance with our discussions and site visit on November 30, 1995. This report includes descriptions of the subsoil and groundwater conditions found in an exploratory boring - and recon:mended dcs!gn and construction criteria for new foundations. The report was prepared from data dc'. eloped during field and laborato%' investigations, engineering analysis of tile field and laboratory data, and PBT's experience wi:h similar projects. Tke recommendations presented in this report are based on the proposed general remediation plan discussed to date with the City Revisions of the remediation plan could affect reconunendations Il'plans change PBT should be contacted A summap,.' of findings and conclusions is presented below, and detailed recommendations for design and construction are presented in the report 2.0 SUMMARY OF CONCLUSIONS 1 Subsoi!s found in the one (1) explorato:y boring (Figure I) consisted of sandy clays to a depth of -- ~ 6 5-feet, underlain by clayey sands with intermittent sandy clays to the maximum depth explored of 50-iL, ct below thc existing grade. Groundwa:er was encountered in the boring, 16-feet below the existing grade, during drilling. 2 The most long ter~n and effective new foundation for the outfall struc:ure would be a deep __ tk, undation system, which would resist the effects of future scour beneath an.',' nexv outfall structure. St:-aig?:t sided dril!ed shalis (piers) or driven piles are considered in this report Detailed design and construction criteria are also presented 3 'Die c~cekside or'the d!ke should be ~estored to near its original condition, so tile integrity of'the d:.l-:e ,s no'. mrtnc~ con:p~olnised The usc ora stabilized toe and/or rip-rap should be considered -- :::, hmn t:.~ture scour and increase st:.~:,ht5 o, tl.c ~c~.,.~cd creeks~de dike slope 3.0 SITE CONDITIONS The o:~:Et!l s::'ucture is cur..-ently located on the north side of Andrew Brown Jr. Community Park, and feeds Den:on Cftc;... ,-. Coppell. Texas [Fig 1) Although the exact location of the subject outfall has not been Pa*~on, Burke & Thompson Engineering Consultants Andrew Bt-own Jr Comm,.uni.'.y Park Outfail Su-ucture Pa~-e 2 -- ~denufied the ou:t'a',l structure which was the subject of this investigation is referred to by the City of Coppell as Project DR95-03 The site, fi'om a south to north direction along the existing outfall pipe, consists ora very flat (20 to 1) grass slope within approximately 20-feet south of the crest of the existing dike, at that point the landward side of the Denton Creek dike is on a slope of approximately 7-1/2 to 1. The crest elevation of the existing dike, at the time '- of the field investigations, is around elevation 459-feet and the dike crest width is very minimal. The existing creekside slope of the dike, outside the area of erosion and sliding in the vicinity of the outflow structure, consists ora relatively steel> grassy slope in the order of 1-3/4 to 1. A significant area of approximately 15 to 20-feet each s:de ofthe center line ofthe 48-inch RCP (see the outline in the plan view on Figure 1) has been eroded or become unstable at the time of the field investigation. Furthermore, the modified dike slope has progressed to a very steep slope x~bich is approximated at between V2 and I to 1 and has progressed in a southerly direction to with!n a short distance o.rthe crest of'the existing dike In addition to the eroded/unstable slope around the outfal[ structure, approximately 13-!inca: feet of the 48-inch RCP and associated concrete head wall structure has been undermined and dropped 4 to 5-feet vertically. This movement has broken the pipe and exposed it freely to Denton Creek ilo,,','. [Note The dcscrii.-.-cd condition of the existing pipe and ouffall structure are based primarily upon visual observations and :!;e City's provided measurements.) 4.0 PROPOSED REMEDIATION It is Pl?,T's understanding at this time, that the City desires to re-estab!isk a gate vane control for the subject -- RCP. an,:! to dexc!oF- stab:.l:.ty to:' botk any ne~ head wall structure and surrounding slope at the subject location. All .,emec!!a:!on alternat!ves thUS: balance flooding protection for the park lakes and overall cost of new const~c:io.n -- 5.0 FIELD AND I.ABOIL. XTORY INVESTIGATIONS ~t,b:t...,t~,. conditions, due to difficult accessibility to tile actual damaged outfall structure, were investiua:ed t,.'..' driliS:g a single explorato,'5' boring approximately 8-feet east of the centcrline of the existing RCP and near S:a.'.~on "'.. - I ', t,:ee.... F¢2ure_ ! ~ The b,.r.~.=',;,, x~,,s'~' drilled with a trt, ck-mounted drill ri~,_ and 4-inch continuous Patton, B~rke ~ Tlxompson Engineering Consultants An&cw Browr. Jr. Communit)' Park Outfall Structure -- Page 3 -- flight augers Representative samples of the subsurface materials were obtained by employing shelby tube and split- spoon sampling procedures Undisturbed samples were obtained of the upper "clayey" soils by hydraulically -- pushing shelby tubes. A soil sample (disturbed) was obtained of the deeper "sandy" soils by driving a 24-inch long spl!t-spoon sampler into the subsurface materials using 140 lb hammer falling 30-inches (i.e., Standard Penetration - Test, SPT). The number of blows for each 6-inches of penetration was recorded, and the total number of blows required to d:ive the second and third 6-inch intervals constitutes the standard penetration resistance in blows per - foot. referred to as the "N" value. The N-value is used to evaluate the engineering insistu consistency properties of' the subsurface materials. Log of test boring showing visual descriptions of subsurface materials encountered are included in Figures 2A and 2B. Sampling information, pertinent field data, and field observations are also included. The laborato~' testing program was directed toward evaluating the physical characteristics, classification and shear strength of the soils encountered in the boring. Laboratory testing of the soil samples included visual classification: moisture content, d:x.' density, sieve analysis, Atterberg limits and UU Triaxial. Results of laboratory testing are presented on the l.og of Boring, Figures 2A and 2B, and Table I 6.0 SUBSURFACE CONDITIONS The subsurface conditions encountered in the one (1) exploration boring, for the purposes of this study, ._ consisted of 16-1/2-feet of stiffto very stiffsandy clay underlain by a medium dense clayey sand to a soft to stiff sand? day stratun: x~ kith extended to thc maximum depth of the boring of 50-feet or approximately elevation 408- - ibc: -- 1-he upper sandy clay soils extended to an elevation of approximately 441.5-feet, which is approximately 3-tk-ct !o'~er than the existing flox~line of the 48-inch RCP. These clays are dry at the surface, but become moist - '¢.i:h depth anti the Atterberg 15nits test indicate these clayey soils have a liquid limit between 59 and 36 percent, a i:ia4ticity index bet'~:ecn 15 ant! 32 percent and 58 to 79 percent fines (i e, ,.ninus No 200 sieve). These soi!s can --- bc classified as mediun; to high plas.-'.ic~tx. CL to CI I mate,-ials Unconsolidated-und:ained triaxial shear strengths ol'thcsc soils le g. UU 'l'riaxial tcs:l ;ndicatc peak shear strengths ia the order o1'2,900 to 4,600 psf Patton, Burke & Thompson Engineering Consultants Andre',,,- Brown Jr. Corpznurdty Park Ouffall Structure -- Page 4 -- The underlying clayey sand to sandy clay soils (from a depth of approximately of 16-1/2 to 50-feet below the existing site grade), were generally moist to wet, and are believed to be geologically floodplain alluvial deposits --- of Denton Creek These deposits generally varied back and forth between clay sands and sandy clays and did not appear to densi~: significantly within the depth explored. Based upon one standard penetration test at the 48.5 to .... 50-foot interval, these deposits can be described as medium dense and can be further classified as low plasticity, SC to CL materials Groundwater was encountered at a depth of approximately 16-feet upon completion of the boring, which is near the interface of the upper clays and lower sands. However, the groundwater level at this site should be expected to be primarily controlled by the water level in the adjacent Denton Creek. Further details concerning the subsurface materials and conditions encountered are shown on the Log of Boring. The stra'.ification line shown on the Log of Boring represent only approximate locations of changes betx~een soil types, as indicated by the field methods utilized. 7.0 DESIGN RECOMMENDATIONS __ The ibllo:~!:'..g desie:: recommendations have been developed based upon PBT's understanding of' the generally desired re:ned!ation cons.'.ruction and subsurface condi:ions encountered in the test boring. If there are -- any major changes in the prc.~cc-', ctesign criteria, a review should be made by this office to evaluate if any further field exploration and:or modifications to recommendations contained herein will be required. The vist,a[ly obser,'ed failure of the subject outfall structure (and related sliding and instability of the slopes - surrounding it) and the subsu:'f:ace conditions encountered in the test boring indicate that in all probability scour occurred beneath the ai.-ron slab of the concrete outfall structure This scour of foundation materials could have - occurred fi-om both south;va:d flow through the pipe from Denton Creek and northward flow into Denton Creek. ,~.~.,...ut a deep toe ,.~.'aH and/or deep foundations beneath the outfall structure, can rest,l: in hilt:res due to loss or' foundation support Ou,' experience with similar failure cond!tions (i.e., both the fi>.mdation st;ppoil I;2.:- the outti:l! s:rt:ctul-e and the surrounding dike slopes) indicates slope strengthening and deep .....£'-, nd. '-,~,.. ss,.~.u,o't,', ~-' L'e utilized K>:- .,.%', ', term s~ab.ht5.''' : ' · Desiun~ and construction r~zco,nme,~dmions fur this desired Burke d~ Thompson Engineering Consultants Andrew Brown Jr. Comr,,unity Park Ou!fall Structure -- Page 5 -- ahernative, and other alternatives with more risk, are included below: - ' 7 I Outfall Structure Foundations It is recommended that the outfall structure and any damaged section of the existing 48-inch RCP be reconst:-ucted to their original location and elevation by supporting them on a deep foundation. A deep founatation consisting of either driven piling or drilled shaft construction are considered satisfactory. For design of driven piling it should be assumed that skin friction be neglected above elevation 440, and a maximum allowable unit skin friction of 1,000 psfcan be used in the Iox~er clayey sands and sandy clay soils for compressive loads An allowable unit skin friction and uplift for these soils should not exceed 50 percent of the allowable values for compressive loads. Based upon our past experience, end bearing should be neglected for design of any non-displacement piling (e.g., steel H-piles), but for displacement piling a maximum allowable unit end bearing value of 4,000 psf at an elevation of 420 or lower can be used. For example, the estimated allowable load capacity in compression for a 12-inch diameter, closed-in, steel pipe pi!e, and cc'.ncrete filled founded at a typical elevation ofapproximate[y 420-feet, would be 16 kips. This _ same pipe pile extended to a tip elevation of around 410-feet would have an allowable load capacity of 21 kips. In a similar manner, it is estimated that a 10-inch steel H-pile would have capacities of 22 kips at a ._ ti:.: clc:'al!on of 420 and 33 kips at a tip elevation of 410. Furthermore, it is estimated that the existing concrete outl~ll structure (including the current iron flat gate) has a total weight less than 30 kips, which - v, oul(~ -on!y require t~o (2) or three (3) piles for suppor. -- :\n aherna.'.ive to driven piling ',~ould be to use straight-sided drill sha~}s founded in the lower clayey sands and sand', cla;'s Similar to the above criteria for driven piling, the sha!is should neglect any skin friction -- ir: soils a:oove elevation 440 and penetrate to a minimum elevation of around 420..4m allowable shaft fSctior., of !,000 psf may be used for compression loads and a maximum allowable unit end bearing value -- o!'2.0'.)0 ps£ An allowable unit skin friction and uplift should not exceed 66 percent of the allowable value f:)r cc, m?ressive loads. In addition, a nfinimum shaft diameter of 18-inches should be used for the design of any straight-sided shafts, and steel casing, based upon the nearby Denton Creek and findings in the boring, wi!l be required during the installation of sha~s to prevent caving of the saturated clayey sands. Putton, Burke d~ Thompson Engineering Consultants Andrew Brown Jr. Community Park Out£all Stract2re -- Page 6 - Regardless of the type of the final foundation selected, the slab apron for the reconstructed concrete outfall structure should be adequately protected to resist future foundation scour. The depth of scour protection needs to extend several feet below the RCP's flowline for long-term protection, but from a practical and balanced point-of-view 2-feet is recommended (Note: Furthermore, if the toe platform recommended in below subsection 7.2 is utilized and extended beneath the subject slab, it will provide a certain degree of scour protection). 7 2 Creekside Slope Stability The current condition of the creekside slopes in the `"icinity of the subject outfall structure appears to be in a progressive toe cutting - sliding - erosional mode If allowed to go uncorrected, regardless of the foundation support provided for the outfa'.l structure and pipeline, this could (with time) result in the breeching of the existing dike embani~ment along the pipe Furthermore, due to the presence offiox¥ing water in nearby Denton Creek and the limited working area, a simple, inexpensive but long-term satisfactor3..' solution may be difficult to design. Desirable elelnents of any design criteria for subject slopes, in our opinion, would involve flattening the final _ slopes around the outfall structure as much as is possible and properly benching any new' construction adequate!y into undisturbed existing dike materials. It would be highly desirable to perform any such ._ reconstruction during Iow water periods for Denton Creek and to initially provide a non-erodible and stable base at the toe of the final reconstructed slopes (e.g., a 3 to 4-foot thick toe platform of either large rock - rip-rap: cement treated based-typ, e :naterials, flowable fill, etc ) .-\i~.er the toe platform has been established, ,,l-ope~:. .... recons'a-uction of tl'.e creekside slopes should be carried out with a final maximurn (i. e , ilo steeper --- ti:an) slop. e of 2 to 1. Suitable soil materials ibr the reconstruction slopes could be similar to the sandy cia,,' materials ei:coumered in the top. 16-feet oftb. e test boring More specifically, ho:vever, such ne'er dike -- should be a clean, mediu~n expansive soil tnateriv, l, free of excess silt, organic matter, wood, any rock ,~,mments :aru~:r than 3-inches and an,.' other g. enerallv foreion materials. Plasticity index of these materials -'- should be more than 10 but less than 25, a liquid limit not exceeding 40 and not more than 50% by weight sha'z be ih:er than a No 200 sieve Such dike fills should be placed in maximum 8-inch thick loose lifts and '- !:e co::'.pac.:ed to a .m!nim'.:n; of 100% Standard Proctor density C-\STM D698) with compacted moisture Pu~ton, Burke & Thompson En§ineer;n9 ¢onsultonts Andrew Brox~ Jr. Community Park Outfall Structure ' ' Page 7 -- contents from I% dr3' to 3% wet of the optimum moisture content of the materials. Each lift should be inspected and tested to yetiS, the in-place thickness end compaction before another lift is placed. 8.0 DESIGN REVIEW It is recommended that PBT be provided the opportunity for a general review of the final foundation and - site reconstruction plans and specifications prior to construction to confirm that earthwork and foundation recommendations presented t:erein are properly interpreted and implemented into the overall project's design and construCtiOn documents. This recommended post-investigations service is not part of the initial scope of work for this study and would be an additional sex~'ice However, PBT cannot be responsible for misinterpretations of our recommendations if not al'.owed an opportunity to review (or at least discuss) these documents. In addition, further analyses may be nccessar3' as final plans are developed and PBT can provide additional analysis and/or consultation as requested 9.0 LIMITATIONS _ The findings and recommendations presented in this report are based on the assumption that subsurface conditions do not x ary appreciably from those encoun:ered at the boring. The subsurface information presented -. in this report does not constitute a direct or implied warranty that the subsurface conditions at the boring location can be directly interpolated or extrapolated. Subsurface conditions which are different from those disclosed by the .... boring ma)' be fot'lnd during construction. - Patton. B:::-ke & Thon:pson has prepared fi:is report to aid in the evaluation of the site and to assist in sta!,'2izatior: and reconstructio:~ of tile site Facilities We have developed our conclusions and recommendations in -'- acco:-dance '~:.th ge~:c:aliy accep:ed professional e, eotechnical engineering principles and practices. We make no ot!:er x~arra.':tv, either ex:3..:-ess or implied Our conc~u_,' -'on~ are based on tile results of the limited field explorations. labora:ory tests, a.,:d ou:' !;::erpre-'.ation of subsurface conditions. If conditions prior to or during construction Pdton, Burke & Thompson Engineering Consultants A:vArew Brown Jr. Comanunity Park Ouffall S:ruct,are -- P~ge 8 -- appear different from those described in this report, we should be notified so that we may review and verify or modi~: our recommendations. Enxironmental issues regarding this site are not addressed in this study. Only geotechnical recommendations '" fbr use in design of specific constructior, elements, earthwork and "quality control" testing and observation of const,,-uction are presented herein. Furthermore, the firm of PBT does not practice or consult in the field of safety '- engineering and any designer or contractor should notiS' the City if she/he considers an3' of the recommended actions presented herein to be unsafe_ Patton, Burke & Thompson Engineering Coasultants FIGURES IW 0 ........... 450.00 >, "x 'x .. _ 'x,.x ., ', x ' Vicinity Map ......... '~ .......... ~ /-'" '-~. _ __ " Verh: 1' = 6.7' ~ Fiorz.: ' = ~6.0' Note: Drawing approximately to scale i-~ica~es cpp~ox~mote of ex~lorato~:, boring -t~-- ~ g ~ Q 8l~ "'~' ~ ~ ~ a~ ~ Irformcfion on this figure taken BORING LOCATION PLAN o! o o~- o oi~ o ~o ~ from C"y cf Coppell's Sheet 1 .. . . d ~ ~ ~[ ~ ~ ~, 'or proiec~ Nc. DR 95-03 Cob No. 101-003 Coppe:l, lexes F z"on, Bt:r.,e ;;; lhcm3soq Figure 1 LOG OF BORING NO. B-1 CLIENT: City of Coppell LOCATION: Coppell, Texas JOB NAME: Brown Community Park Outfall RIG TYPE: CME-55 DRILLING CONTRACTOR: Core Test LOGGED BY: RJH SURFACE CONDITIONS: Grassy/slope DATE DRILLED: 12i05/95 GROUND ELEVATION: 458.0' JOB NO.: 101-003 PAGE 1 OF 2 - FIELD DATA LABORATORY DATA DRILLING METHOD(SI: Continuous flight auger ~ ~ --~ROUNDWATER INFORMATION: 16' after completion of , ~: u. O ~- ~ ~ ~ SAMPLE TYPE ~ ' ' , ~ ~ ~ ~ - ~ u ~ ST Shelby Tube RC R~k Core SS SpEt Spoon ~ = I~ ~ ~ GEOTECHNICAL DESCRIPTION ~ ~? C~Y, sandy, ve~ stiff to stiff, dry to mo;st (CL, CH) S4:9.0.:C.3 ST P=4.5- ~9 108 59.27 32 79 -- 20 21 -- ;"~'//~ SAND. clayey to ~ndy clay, soft to stiff or medium donse '.."'.." I :o dense, moist to vgry moist, brc~'nish yellow, I:ght browc . ?/. ~SC, CL) $7 2-' C.-:.![.C C'I ]g 31 '$ 13 58 ' -- 25 30 ........... I ; '/ -- N - STA,~DARD PENETRATIvN TEST RESISTANCE REMARKS: Boring backfilled with cuttings upon completion FIELD T - THD COI~;E PENETRAT;ON RESISTANCE P - POCKET PEN_?RATION RESISTANCE of drilling TEST R - PERCENTAGE OF ROCK CORE RECOVERY RQD - ROCK QUALITY DESIGNATION - Patton, Burke & Thompson Figure - 2A LOG OF BORING NO. B-1 '- CLIENT: City of Coppell LOCATION: Coppell, Texas JOB NAME: Brown Community Park Outfall RIG TYPE: CME-55 DRILLING CONTRACTOR: Core Test LOGGED BY: RJH SURFACE CONDITIONS: Grassy/slope DATE DRILLED: 12105/95 GROUND ELEVATION: 458.0' JOB NO.: 101-003 PAGE 2 OF 2 -- FIELD DATA LABORATORY DATA DRILLING METHOD(SI: Continuous flight auger GROUNDWATER INFORMATION: 16' after completion of '-- : ; ~ i:~' =~ u~ ~ drilling ~' u. :~ ~ ~ '~ ~ ~: - o ~ ST Shelby Tube RC Rock Core SS Split Spoon ~- =' .-~ .~ O -. ~ CT Cuttings TC THD Cone CS Cal;fornla Spoon =r-o.== " .~ =. F_ ~ ~ GEOTECHNICAL DESCRIPTION .. SAND, clayey to sandy clay, soft to stiff or medium dense - to dense, moist to ver~ moist, brownish yellow, light brown (SC, CL) 35-- 40-- ! ;,-...,. 45 -.' _ S8 4a.5-EO.O SS' N=13 21 .//'~.:. .50 :loring terminated at a depth of 50.0' -- 55 -- N - STANDARD PENET.~ATION TEST RESISTA~,.~E REMARKS: Boring backfi;led with cuttings upon complet,o, FIELD T - ~ H~) CONE PENETRATION RESISTANCE P - POCKET PENETRATION RESISTANCE of drilling TEST ~ · PERCENTAGE OF ROCK CORE RECOVE-~Y .~QD - ROCK Q.JALITy DESIGNATION '-- Patton, Burke & Thompson Figure 2B Boring Depth Material Moisture Dry Unit Confining Peak No_.~. (ltl Type Content (%) Weiclht (pct') Pressure (pst') stress (pst') B-1 4-5 CLAY, sandy 11 103 500 5868 B-1 9-10 CLAY. sandy 17 108 1000 9259 TRIAXIAL COMPRESSION TEST -- Yest :,re ~S~r-~ C ;SS0- C'~ SUMMARY OF RESULTS Denton Creek Outfall -- Andrew Brown Jr. Community Park Job No. 101-003 Coppell, Texas __ Patton, Burke & Thompson Table 1