5902 EVERGREEN WAY HOUSING HOPE 2018-01-01 MF Import

i Subsurfaca Erploration, Geo[vgic Hazard, a^d 1 Norccing ffope Pharc 11 Prtliminary Gcotechnical Engintering Rrport e'vrrrrt, Was/dr.gron Project and Sia Conditiant � 7t should be noted that differing subsurface conditions may be preseat<;:ae to the random nature of depusitio�: and the alteration of topography by past graJing and/or rilling. The nature and extrnt cf any variations beaveen the field e:;plorations may not become fully evident ttncil � conswction. If variations aze observed at that time, it may be necessary to re-evaluate sFe:ific rrconimendatio�u u� this report and m�ke appropriate changes. i 3.1 Exploration Pits i I. Exptoration pi.s were excavated ��ith a track-mounted backhoe. The ex�loration piu permitted direct �•isual observation of subsurface cor�ditions. biaterials enccuntered in the exploration pits �ti•ere stUdied and classified i❑ dte field by a geotechnical engineer from our firm. All I esploration pi[s were backfilleci unmediately after examination and logging. The exploration pit backfill was tampeci in p1acA with the bacl:hce bucket. Therefore, the are2s explored will require re-excavatio❑ to [he depths explored and recompaction in conformance with our � recommendations. 5elected samples were then transported to our laboratory for further visual classification ar.d testing, as necessary. The samples will be maintained in our laboratory until intilvatioo system details arc developed and future [esting requirrment� are determined. I � 4.0 SUBSURFACE i3ONDITIONS ISubsurface conditioas at the project si[e were inferred from the field explorations completed I For th;s study, visual reconnaissance of the site, and review of applicable geologic literature. As shown on the field logs, the exploration pits completed along the western site margins generally encountered loose fill overlyin� natural deposits of glacial recessional outwash � consisting of clean, loose to dense sand with varying amounts of silt and gravel. In the eastem porcion of the site, these sedimens were underlain at shallow depth by gray silt with sand, gravel, and cobbles interpreted as tilL Till was identified b�neath the recessional outwash in 1 all exploration pits except EP-3. The depth to medium dense to dense bearing strata has been � identified in brackets on Figure 2. I We reviewed the Distribution and Description of Geologic Units in the Everett Quadrangle, � Washi�rgton prepared by bfinard in 1981. This publication s6ows the site is underlain by Vashon till. The glacial sediments in the site vicinity were deposited during or shortly afrer I the Vashon Stade of the Fraser Glaciation approximately 14,000 to 17,000 years ago. Recessioual outwash consists of sand and gravel that was deposited by meltwater streams as the glaciers were retreating to the north aker the last period of glaciation. The recessiona] Ioutwash deposi[s on the site appeaz to be a localized channel deposit. Till represents the ground moraine of the southwatd advancing glacier and generally underlies the outwash at � depth. � Frbrunry ll, _'/,fl? ASSOClA7ED F.1H7NSCIENCE$ INC. sc�r,m�xEnr-+c,�:-rA�«u�:ao��+mK�wr u:K P�ge3 � ` �� I