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� <br />It <br />' <br />' <br />' <br />' <br />' <br />� <br />Jauuary 22,'_003 <br />HWA Projcc� No. 200?-I85 <br />loosened and soflened sc�ils. 'I'hc pipe bcdding shuuld c�tcnd up the siJcs uf thr pipcs to <br />at lcast lhc spring line, and prefcrably to G-inchcs abo��c thc lop oFpipc. l�hc heddin�� <br />should be compacted under/around the pipe and pi�x haunnc�s to cnsurc unili,rm s�µ�pui�t <br />forthe pipe. <br />If the trench spoils remain dry, lhese malerixls cun bc rcuscd as Ircnch backlill in <br />nomstructurul areas where several inches of setUcment can be tulerated. lio�cc� cr, thc <br />soils are highly moisture sensilivc and if exposcd to ground �vatcr ur sm•face ���atcr, may <br />be impossible to rewmpact. If the soils bccome too wet fi�r compaction, ��•e recununend <br />imported granular soils be used instcad. .. <br />During plucement oCthe initial litts, trench backfill m�tcrial should nut be bulldozed inlo <br />the trench or dropped direcUy on the pipe. Furthemiorc, hcu��y ��ihralory equipment <br />should noi be pennilted to operalc direcUy o��cr the pipc witil a minimum of 3 fcet of <br />backfill has been placed. <br />R'et Weather Earth��•ork <br />The silry sand surticial soils arc highly moisWre scnsiti��c and may be dillicult tu lraverse <br />with construction cyuipment during periods of wel wcathcr. Gencral recommendations <br />rclative to earthwork performcd in wet weather ��r in �ect conditions are presentcd bclow. <br />These recommendations should be incoiporated iAto thc contract spccitications. <br />C • Earthwork should be perfonned in smaU areas lo minimiu exposure to wet Ncatlier. <br />Excavation or the removal oF unsuitable soil shc�uld bc fi�llo�ved prompHy by the <br />placement nnd compaction of clean struclural till. l'he si-t.c and type of construction <br />cyuipment used may need to bc limited to prcvent soil disturhancc. <br />� <br />• Malerial used as structural fill should consisl of clean granular soil with less than 5 <br />peroent fines. Thc fines shuuld be nun-plastic. <br />• Thc ground surfacc �vithin lhc consU•uclion arca should hc maintained to promotc run- <br />off of surface water and to prevent Ihe ponding of ���.�lcr. <br />• The ground surface within thc constivction arca should be sculed by a smooth Jrum <br />viUralory rollcr, or cyuivalcnt, and undcr no circumstanccs should soil be lefi <br />unrnmpacted and cxposed to muisture. <br />• 6xcavatiun and placement of structural fill matcrial slwuld bc observed by a <br />rcprescntative uf thc gcotechnical cngincer, lo dcl�nnin� lhal lho �vurk iti bcina <br />accomplishcd in accordancc wi�h lhc projcct spccilicaliuns and thc rccomnundations <br />conlaincd hcrcin. <br />200?-IR> Suppl LR.dot <br />II\\'A GeoScicnccs Inc. <br />I <br />33 <br />