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Thomas Jones �N yepsp <br /> March 14, 1090 Ppe 7 <br /> The values piven above are to be used to desfpn p�rtnanent foundatlon and rota(ninp wailt only. <br /> The passive proaauro given la approprlats for the depfh of IsvN, sWctural fill placed in iront of a <br /> rotafning or foundatlon wall only. We recommend a safs�n c�tor of at least 1.5 tor overtuminp <br /> and slid(np, when usinp the above rocommended values to d��Ipn fhe walls. <br /> The desipn valuea piven above do not indude ths eflects cf my hydro:tatic protauroa behfnd the <br /> walla and assume that no su�charpe slopei or loads, �uch as whidea, will tre placed behind the <br /> walls. If these condftlons exist, those proisuns �hould b� addsd to th� abow lat�ral toil <br /> prossuros. Al:o, if slopinp backfill is d�sind behind tM wall=, we w(II nsed to be piven fh� wall <br /> dimenaiona and ths stops of the backflll in order to provids the eppropriats desiyn earth <br /> prossuros. <br /> Hsavy conaWctlon equfpment ahould not be operatsd behfnd rotaininp end found�tlon wall� <br /> within a distance equal to tha heipht ot a wall, unleaa the walts are desipned }or the addftlonal <br /> lataral pressuroa reaulUnp from ths equfpment The compactlon of backflll near the waiis �houtd <br /> be accompliahed with hand-aperated equipment to provent Me walla irom bsinp oveAoaded by the <br /> hipher soil forces that occur durinp compectlon. <br /> Retaininp Watl Backflll <br /> Backflll placed behind rotafninp or foundatlon walls �hould be co�ne, tns-dra(nhip, <br /> atructural flll containinp no orpanica. Thia b�Gcfill should contain no moro than b perpnt <br /> silt or Gay partidea and have nc+ yravsl prsater than� inche� in diameter. Ths percentaps <br /> of parNclea paaainp the No. 4 alevs ahould be betwesn 25 and 70 percent Due to their sift <br /> contents and flne flrain aize, the nadve aoil and on-aite flll aro not suitabls as rotaininp wet� <br /> beckflll. For increased protecdon, drainepe compo�itss could be placed alonp cut slopa <br /> faces, and the wells ahould be backiflled with pervioua sofl. <br /> The purpose of theae back}ill roquirementa la to enturo th�t ths daipn afteria for a <br /> retafninp well are not exceeded because of a bulid-up of hydro:taUc prossuro behind the <br /> wall. Tha top 12 to 19 inchea of ths backflil ehould contiat ot�rolatively impermsable wil <br /> or topsofl, or the suAacs ahould be paved. Ths aub-aecBon enHtled f3�rwnl Earlhwork <br /> and Structural FIII containa rocommendatlona repardinp fhe placement and eompactlon of <br /> atructural flIi behind retaininp and foundatlon walla. The above rocommendaUont �n not <br /> Intended to waterproot the below-prada wall�. If moist condiUons or soms seepape <br /> through the walls are not acceptable, damp-prooflnp or waterprooflnp :hould bs provided. <br /> This could includa IfmiUny cold•Joints and wall panetratlona, and poasfbly usinq bentonits <br /> paneis or membranes on the outside of the walle. Applyinp a thin coat oi eaphelt emulslon <br /> is not conaidered waterprooflng, but it will help to provent moisture, Qenerated from water <br /> vapor or capillary acUon, from seepfnp throuph ths concrots. <br /> Excavations�nd Slooes <br /> Excavation slopes shouid not exceed the Iimfts specffied In local, state, and natlonal govemment <br /> safety repulaUons. Temporary cuts to a depth of about 4 feet may be attempted vertically in <br /> unsaturated soii, if there are no indicaUons of alope instability. Baaed upon Waahinpton <br /> Administrative Code (WAC) 298, Part N, the aoil rype at the subJect aite would be classifled a� <br /> OEOTECH CONBULTANfl,ING <br />