1136 GRAND AVE A&B 2016-01-01 MF Import

. � April 23, 2007 Mr. Scott Andcrson L&A Job No. 6A 126 Pagc 3 undisturbcd and wcll-dr�incd, thc lresh till c:ui providc cxcellcnt foundation sup�rt with litdc settlement cxpccted. The advance ouhvash soil unit underlying the Vashon till is composed of stratified sand and gravel with minor amounts of silt and clay, deposited by thc meltwater of advancing glacial ice. Due to thcir generally granular composition, lhc advance outwash dcposits are of moderately high pertncability and generally drains fairly well. The advance outwash deposits are glacially overridden and are gcnerally dense to very dense in its natural, undisturbed state, except the top 2 to 4 tcet whcre exposed on slopes which may be weathered to a loose to medium-dense statc. Thc advance outwash deposits can stand in steep cuts or natural slopes tor extended period when undisturbed. Whcre exposed on slopes with poor vegetation cover and subject to stottn runoff or groundwater scepage, the advance outwash deposits can be gradually eroded and may slough and redeposit to a tlatter inclination. The underlying :resh �dvance outwash deposits in their native, undisturbed slate can providc good foundation support with littic setdcment cxpectcd for light to moderate residential structures. A stecl T-bar was manually pushed into thc surlicial soils from the east boundary ol the sitc to the crest of the stecp slope in thc westem portion of the site to get an indication of the density or consistency of thc soils. The probc could pcnetrate to about 6 to ]0 inches in the front yazd and to about hvo feet in ihe backyard. The ground probing results indicate that the site is most likeh� underinin by very-dense, fresh till soils at ��ery shallow depth. Groundwatcr Conditinns The fresh till soils at very shallow dcpth ,irc practically inyKrvious, while the underlying advance ouhaash soils arc of modcratcly high permcability. Stormwatcr infiltrating into the surficial more LIU & ASSOCIATES, INC.