4937 SEA BREEZE WAY 2017-01-13 - Laserfiche WebLink

� Geotechnical Engineering Evaluation Pepe Retaining Wall Everett, Washington coordinated with the property owner to the south. • NGA File No. 916915 April 27, 2015 Page 4 We observed a severcly leaning tree on the slope to the southeast of the residence. This tree is sevcrely bowed and leaning towai'ds the house. We recommend ihat this tree be evaluated by an arborist and removed so it does not pose risk to tl�e house. This is discussed flirther in the Conclusion and Recommendations section of the report. Subsurface Conditions Geology: The geologic units for this area are shown in the Distribution and Description of Geolo� Units in the Mukilteo Quadrans�le, Washin�ton, by James P. Minard (1982). The site is mapped as Transitional Beds (Qtb). The Transitional Beds are described as mostly thick beds of gray clay, silt, and fine to very fine sand. O�ir eYplorations generally encountered undocumented fill underlain by gray, silt with trace sand at depth consistent with the description of Transitional Bed soils. Explorations: Tl�e slibsurface conditions behind the wall were explored on April 10, 2015 by excavating four test pits to depths of 2.0 to 8.0 feet below the existing surface using a trackhoe. We also explored the subs�irface with a hand hole loeated on the slope below the retaining walL The appro�imate locations of our explorations are shown on the Site Plan in Fig��re 2. A geologist from NGA was present during the exploi•ations, examined thc soils and geologic conditions encountered, obtained samples of the different soil types, and maintained logs ofthe explorations. The soils were visually classified in general accordance with the Unified Soil Classil7cation System, presented in Figure 3. The logs of the test pits and hand hole are attached to this report and are presented as Figure 4 and 5. We present a brief summary of the subsurface conditions in the following paragraph. For a detailed description of the subsurface conditions, the test pit logs sho�ild be reviewed. Test Pits 1 through 4 were located behind and adjacent to the wall. In all of the test pits, we encountered approximately 0.1 feet of grass underlain by 1.9 to 4.9 feet of loose, brown, silty fiine to medium sand with gravel and garbage. We interpreted these soils to be undocumented fill soils. Underlying the undocuinented till soils i�� Test Pit I, we encountered approximately 3.5 feet of inedium stiff to stiff brown-gray to gray, silt with sand, iron-oxide staining and trace gravel, which we interpreted as NELSON GEOTECHNICAL ASSOC/ATES, INC.