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I <br /> of approximatcly 5 fcet. 7hc till encountcred in thc rcmaining tcst p�ts was vcry dcnse directly below the <br /> fill laycr. <br /> Groundwater Condltlona <br /> Groundwatcr wns obscrvcd at a dcpih of approximatcly 2 fcet in test pit 'PP•1 nbovc thc contact of thc <br /> vcry Jcnsc glacial till. No groundwatcr sccpagc was observcd in thc othcr icst pits and groundwatcr was <br /> nol encountcrcd during dnlling of the borings. A perched groundwater condition is common above <br /> gincinl till dcposits as secpege from prccipitation and surfacc watcr ianoff infiltrates through the upper <br /> I wcalhered xones or within fill soils above Ihe till and movcs laterally or perches on the underlying soil. <br /> Wc nnticipatc groundwatcr lo �uctualc with changes in season and precipitation. <br /> I CONCLUSIONS AND RECOMMENDATIONS <br /> I SUMMARY OF KEY GEOTECHNICAL ISSUES <br /> Prom a gwtcchnical standpoiN, ihc dcnsc nativc glaciul sails will providc cxcellcm foundation support <br /> for thc proposed mcr�aninc. Both thc glnciul lill nnd silty sand fill soils are moiswrc scnsitivic end w�ill <br /> I hecome cnsily diswrhed during thc wi�iter scason. Wc rccommend carthwork and site groding for thc <br /> proposcd new cntrances hc complctcd during thc dry scason to reduce carthwork wsts. The following is <br /> a summary of the kcy geotcchnical issucs rclatcd to site devclopmcuL Dcsign Icvel rccommendations for <br /> I cach of thcse ilcros, as well ns other important geotcchnical recommcndations for ihe proposed project, <br /> arc containcd in suhsequcnt sections of this rcport. The cntirc Conclusinns nr�d Recomme��dntinns section <br /> should bc rcvicwed to ohtuin pertinent geotechnic�l rccommcndations. <br /> I • 'I'he existing fill soils and native glacial till have significant fines content such Ihat rcpeated <br /> construction IralTic will result in considcrablc disWrbancc during wcl wcathcr construction. If <br /> practical, we rcwmmend sitc grading and subgmdc preparation bc accomplished during extended <br /> I periods of dry wcathcr whcn thc surficial soils will bc Icss susccptiblc to diswrbancc. ►f wct <br /> wcathcr conswction is rcquircd, a thickcr subbasc laycr can hc considcrcd in combination wilh a <br /> scparation gcolcxtilc fabric. 'I'his is discusscd in morc detail in thc Sitc Prcparation scction of this <br /> I rcpurt. <br /> • A perchcd groundwaicr condition should bc anticipatcd during thc wct scason from prccipitation <br /> and surlucc watcr runnff thal may infiltratc thrnugh thc upper fill and movc latcrolly on thc Icss <br /> pertncablc silry sand. Wc .nlicipatc Ur+t groundwatcr cncountcrcd durinE cxcavations can bc <br /> adcyuatcly handlcd with collcction ditchcs nnd sump pumps. <br /> • Shallow foundations are suitablc for support of Ihc proposcd mc7aaninc. <br /> • Wc rccommcnd an allowablc soil bcaring pressurc of 3,000 pounds per squarc foot (ps� bc <br /> u�ilizcd for dcsign of footings supportcd on struclural fill ovcrlying dcnse nativc till soils. <br /> "I'his valuc can Ix� incrcascd to 8,000 psf for footings foundcd dircctly on Ihc vcry dcnsc <br /> glacial till. <br /> � 'I'hc ahovc dcsign valuc has a I'actor of safely of at Icast 3 for dcad plus long-tcrtn livc loads. <br /> � for sliort-lcrni iransicnl loads (c.g., scismic, wind loads), thc allownblc bcaring capacity can <br /> hc incrcnscd by onc-third if permilted hy Ihc dcsign standard. <br /> • All exlerior f��iings should be founded at Icast 18 inches below the lowest adjaccnt finished <br /> grade, while inlerior footings may be founded a minimum af 12 inches below top of slab. We <br /> rccommend minimum f�-�t;ng widlhs of 16 inches end 3 feet for continuous and isolatcd <br /> liiu�ings, respcclivcly. <br /> ( <br /> I l7lrNn 21145-0/4-ll.t Pagr3 (�7EOENGINFLII� <br /> Vn�. n jlNI4 <br />