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� <br />� ( <br />' <br />1 <br />' <br />�,���„�y zz. �oo� <br />HN'A Projcci No. 200'_-ICi <br />anJ locations mpurtcd and, Ihcreliirc, arc not iuccssaril�� rcpi�cscnt�ticc of uthrr locations <br />and times. , <br />L.uso�c,� roKv't'i:sri�c; <br />H WA personncl perlonncd laburatory tcsts in ecncral accurdancc �eilh apprupri:dc <br />ASTM test tnethods. We lested selecled suil samplcs to dctrrminc moisture content. <br />t\ttcrbcrg Limits, ancl ��rain-siu distribution. �loislure contcnl data arc indic.itcJ on thc <br />lugs at thc appropriate dcplhs. '1'hc LiquiJ Limit (LL), PI,islic Limit (PL), an�l Plasticity <br />Indcx (PI) «�cre JctcrmincJ ti�r thc purtiun uf a sciccicd s:miplc p:issing thc No. -{ll sic��r, <br />in gencral uccordancc with AS"I'M U-d3I S. 'I�hc tcst results arc pinttcd on Fi�_urc S. <br />Grain size distributiot� curves lor lhc testcd samplcs aro �,rc�cnlcd un fi�,ures') and 10. <br />_ �, <br />SUI3SURI�ACE CONDI'I'10�5 <br />The supplemental borings encountercd gcncrally similar su�aligrapliy to that ob'scn'cd in <br />our previous test pits and i�dicaled on thc Eurth Consultantx, Inc. (ECI) borines and tcst <br />pits (1998). However, the cf�y encountered in our boreholcs was nwch softer•and of <br />greater thickness lhan lhc clay laycrs indi�alcd on ECI's borings. Also, Icss potcntiallr ; <br />liquefiable sand was encountercd. The cross scc;tion presentcd in Figurc 3 indicates oui <br />inlerpretation of lhe gencral subsurfacc condilions cncountcral in the boiings and <br />selected test pits. Descriptions of lhe units obscrvcd in the supplemental boreliolcs are <br />presented below in order of deposition, beginning witli thc must rcccnUy depositcd. 1'he <br />attached summary logs (Figures G and 7)'providc morc dclail rclativc to subsurfacc <br />conditions oUserved al specific lucalions and dcpths. . <br />Upper Silty Sand ('ill: 'ihc upper 1 I to 14 icct cunsislcd gcncrally of silly, gravclly <br />sand, with variable nmounts of organics, including partl'y Jecomposed woody debris <br />(roots and brnnches). The fill was gencrally mcdium dcnsc, but in BI1-I thc lower <br />portion wus vcry loosc. "1'his unit �+�ns cvidcnlly placcJ :�s lill in lioriwnlal lills (as <br />observed in our previous test pits). <br />Dcta�tion Pond ScdimcnL• Vcry suti clay, from 13 lu 17 fcet thick, was <br />encounlcred in the borings. "Plre clay containcJ parUy decomposed, in-place roodets, <br />along �vilh some finc sand Icnscs in tlic lo���cr portions, indicating thc scdimcnt was <br />likcly dcposiled in place rathcr than having bccn dumpcd as lill. 'Che low blow <br />counts and high moisture conlent indicate the clay is liighly compressible. Atterber� <br />Limits tests indicatc that thc clay is highly plastic, �� ith a nalural moisturc cunlcnt <br />ncarly at or ubove thc liquid IimiL Plustic soils that ha��c moisWrc contcnls al or <br />abovc lhc liyuid limit can dcfimn substanlially duc lo luading. Upon complction of <br />cach boreholc, thc portion within the clay zone tcndcd to syuecze in, furthcr <br />indicating its vcry so�i consislcncy. <br />200?-IR� Suppl I.R.dnc <br />� II1\'A GcoScicnces Inc. <br />