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^�:'I.'.I.�i.�.�:.`,'. C.��'yj� .�`. ��I'��. ��\C. <br />rccommcnd an allo�eablc passivc pressurc of I JO pci .ind 130 pcf, respcctivcly. Both thc <br />cocfficicnt and passivc pressurc ��:�lucs abovc includc a factor-of-safety (PS) of 1.5. <br />10.7 Floor Slabs <br />ln our opinion, floor slabs for thc Administration Garagc and pedcstrian tunncl could consist of <br />slabs-on-gradc. r111 fill placcd undcr slabs-on-�radc, including backfill for iooting excavations, <br />utilitics, etc., should consist of properly compacted stnicwral fill ovcr dcnsc/hard, nativc soil. <br />We estimate that a modulus of suUgradc reaction equal to 250 pounds per cubic inch (pci) for <br />dcnscly compactcd strucwral fill over properly prcpamd nati��c soil and 300 pci (or ��cry <br />densc/hard nativc soil could bc uscd for dcsign of slabs-on-gradc. This rccommcndation <br />assumes th�t proper drainage is provided bencath thc iloor slabs. We recommcnd that a system <br />of subdrains bc installcd bcncath thc garagc (loor slaUs. Rccommcndations for subdrains arc <br />prescnted latcr in this rcport. <br />10.8 '1'emporary �xc:n'ation Shorin�; <br />10.8.1 Oacrvic��• <br />In gencral, Uic sitc is undcrlain Uy vcry dcnsc/I��ard glacially ovcmddcn soils a, rclativcly <br />shallo��� dcpths. \1�e are currently dcsigning soil nail shoring walls Cor temporary suppon of thc <br />Administration Garage excavation. As shown on the attached generalized subsurface profiles, <br />thc ���;�tcr-bcaring advancc ouhvash unit is abo�'c Ihc basc of thc proposed cacavation. <br />Additional zoncs of ���atcrvbcaring matcrial may bc cncountcrcd throughout thc cxcavation. <br />"I'cmpor:�ry dewatcring mcasures will bc required in order to inslull soil nail shoring. Becausc <br />soil nailin� has been chosen as the preferrcd shoring system, ���e recommend that the contractor <br />bc preparcd lo dcal aggressivcly ���ith thc anticipatcd ground���ater conditions before the <br />cxcavation dccpcns to the ground���:uer Ic��cl. We undcrstand that a 20- to 25-foot-deep sanitary <br />sc�vcr pipclinc ���ill bc trenchcd down thc ccntcr of Oakcs Avcnuc possibly prior to soil nail <br />installation. Thc backfill and construction timing of thc scwcr pipclinc installation may also <br />affcct the soil nail design. In gencral, if there are deep utilities under the surrounding strcets, it is <br />likcly that thcre is morc fill prescnt bcncath thc succts than what ���as cncountcrcd in our borings <br />within thc site. Typically, soil nails have a closer spacing and arc longcr when used in fill soils. <br />Temporar�� soil nail shotcrete facing may need to be thicker and have more reinforcing to <br />,i i���:��,,,�.i:: ,:��.�: <br />Id <br />'_ I -I -0�)G 1�1-00� <br />