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, ' , ' 1 1 ' ' 1 ' 1 CJ ' ' , ' , ' Geotechnical �n�ineering Letter Alhuss�ini Slope Stabilization and Ret�ining Walls �verett, Washington NGA File No. 867612 December 10, 2012 Page 3 to 55 percent) as shown on Cross Sections A-A' and B-B' in Figures 3 aud 4, respectively. The slope is currently covered witl� tl�e uewly placed till and straw tl�at was placed on the fill. Durin� our site visit on November 20, 2012, we observed large tensiou cracks alonb the top of�the slope along with soine soil uloveinent o�l the southern porlion of tlle slo�c. The existing site layo��t is shown on the Scheinalic Sitc Plan in Fibure 2. Subsurface Conditions Geology: The beologic units for this area are shown on the Geolo�ic Ma� of the Everett 7.5- Mi�lute Quadran�?le, Snohoinisll Cowltv, Washin�ton, by James P. Minard (U.S.G.S., 1985). Thc site is mapped as Glacial Till (Qvt) and Advance Outwasli (Qva). The glacial till is described as a non-sorted mixture of silt, sand, and cobbles. Tl1e advance outwash is described as clean, sti-atified sand and gravels. Our explorations generally encountered undocumented till soils underlain by silty fine to inedium sand consistent with tl�e description of glacial till soils in some of our exploratious. I;xplorltions: We visited the site ou November 20, 2012 to explore the subsurface conditions withiil the steep slope area aiid proposed retainiiig wall ai-ea with hand auger exploratio�is. Tlie approximate loc�tions of ow� explorations are sl�own on the Sche�l7atic Sil'e Plan in Tigure 2. A �eologist i�ronl Nelson Geotechiiical Associates, Inc. (NGA) was prese�it duriilg the explorations, exa�nined tlle soils and geolo�ic couditions encountered, and maintained logs of the explor�tions. The soils were visually classilled in general accordance witl� the Uiiified Soil Classification Systein, preseuted iii Figure 5. The logs of our explorations are presented as Figures 6 and 7. The following paragraph contains a brief description of the subsurface conditions encountered in the explorations. For a detailed description of tl�e subsurface conditions, the hand auger logs s]Iould be reviewed. Hand Augers 1, 2, and 4 tl�rough 6 ei7countered approximately 3.5 to 5.0 feet of loose, gray- brown silty fine to medium sand with gravcl and varying amouuts of organics that we interpreted NELSON GEOTECHN/CAL ASSOCIATES, INC.