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� , <br /> Any sofl an�as nrncd Juring proofmlling should bc m•cres�a�atcd and replaccJ �cith svucwral � <br /> � 11II 85 OUIIIOCd IICION'. Ir(ICCr�OCI�CIS Of ti0�1 Of�llllll(1111� $OII,are cncoun�crcd, il ma� hc pnssihlc � <br /> I to limit the depth of o��creccavation h� placing a gcotectile reinforcemcnt fahric such as Mirafi <br /> 500\ (or equal) on the o�•crcscavated subgrade and covering the �eotr�tile �rith s�ruciural lill or I <br /> crushcd rock. Tlic gcotestilc will providc additional �upport b��bridginc orcr thc sofl matcrial, and <br /> � �vill help rcducc fines(material passing Ih:No.200 sicve)contaminatirni into the sinictural fill. �I <br /> A reprcsentative of GcoGn�ineers should monitor thc bonom of un�uitablc soil eccavations, <br /> I proofrolling and subgradc coinpaction operalions ro evaluatc if subgradc disturbancc or pmgressivc i <br /> detcrioration is occurting• Preparation of tl�c dilches and tlie south��est c�cavation should also t�c <br /> cvaluated prior ro filling. Subgnde disturbance or dcterioration cot�ld occur if the suhgradc is wct <br /> � and can not be dricd. If tl+c sub�rade deteriorates during proofrolling or crnnpacting. it may bccome <br /> nr.ccssary to modify the proofrolling or compaction criteria or metliods. <br /> � 4.2.4 Excavation of Non-Preloaded Fill Strip <br /> The southem edge of ilic old uncompacled overburdcn stockpile has not been preloaded or <br /> � subjected to loads simulating the proposed building loads. Therefore. the old overburdcn fil! that <br /> has not been preloaded(area shown in Ficure 2)should bc removed to a depth of at least 5 fect and <br /> replaced with structural fill compacted to at least 95 percent of the macimum dry densiry. Tl�e <br /> J bottom of thc cxcavation should eatend at Icast 10 feet bcyond the limits shown in Figure 2 and the <br /> � escaration side slopes should be not steeper than 2H:1 V. V1'e understand that it is desirable to <br /> o�•erescavate these loosc soils instead of using a preload fill. It is critical that this area be well <br /> � sun�eyed in ihe field such that the unsuitable soils are properly removed. <br /> Tlie bottom of the eaposcd excavation should be evaluated by a representative from our firtn <br /> I prior to backfilling the eacavation with structural ftll. Swetural fill placed in the exca��ation should <br /> be benched a min:mum of 3 fect into the adjacent soils on the e�cavation slopes. <br /> ( 4.2.5 Structurai Fill Material <br /> All fill used on the projecl should be structural fill material. We recommend that strucwral fill <br /> � ronsist of properly prepared on-site till soils or imported granular marerial such as pit run sand and <br /> gravel that is free of debris,organic contaminants or rock fragments larger than 6 inchcs. <br /> llie suitabilit��of soil for use as s�ructural fill will depend on iu gradation and moismre coment. <br /> IIn our opinion, glacial till fill excavated from other areas on the site ma�• be used as structural fill <br /> for mass grading and in utiliry trenches (H�here appropriate). Based on our experiunce at the site, <br /> ( the glacial till may be compacted to at least 90 percent of MDD during dn•weather conditions with <br /> Imoderate effort. We rccommend that the glacial till be moisture conditioned to within 3 percent <br /> below and 2 percenl above the optimum mois[urc content. During extended periods of dq�weather <br /> I and whcn the till is within 2 perent of the optimum moisture content it should be possible to <br /> ar.hieve at least 95 percent compaction. Howevcr,glacial till is��ery moisture-scnsitive and difficult <br /> Ito compact when wet. Achieving adequate compsction during e�tended periods of wet weather will <br /> ( <br /> I G c o G n 6 i n e e r s 9 FileNo. 7t84.D02-00.1130\OS0101 (3 <br /> I /� <br />