1915 W MUKILTEO BLVD 2018-01-02 MF Import

Geotechnical Engineering Evaluation and Slide Repairs 1915 Mukilteo Boulevard Everett, Washington INTRODUCTION This report presents the results of our geotechnical engineering investigation and evaluation of the Robinson residence landslide in Everett, Washington. The project site is located at 1915 Mukilteo Boulevard, as shown on the Vicinity Map in Figure 1. The purpose of this study is to explore and characterize the site's surface and subsurface conditions and to provide geotechnical recommendations for slope repair and stabilization. The site contains a steep north -facing slope overlooking Possession Sound and is currently occupied by an existing single-family residence. The residence is situated along the top of the steep slope. The slope below the residence has experienced recept movement during the heavy rainfall of this past winter. As a result of the slide, the portion of the slope directly to the north of the residence has an exposed, near - vertical face of more than 10 feet high with the slide debris deposited on a relatively flatter bench below the exposed face. Tension cracks are evident above the steep scarp. The remainder of the slope (northeast and cast of the residence) has also experienced significant movement, evident by tension cracks and subsidence of the material on the slope, although the majority, of the slope in this portion is still covered with vegetation. Below the affected areas, the slope extends at a moderate to steep inclination down to the existing railroad tracks along Possession Sound. For our use in preparing this report, we have been provided with an untitled, undated site plan showing the property lines and existing site features prepared by CG Engineering. SCOPE The purpose of this study is to explore and characterize the site surface and subsurface conditions, and provide general recommendations for slope repairs and stabilization. Specifically, our scope of services includes the following: I. Review available soils and geologic maps of the area. 2. Explore the subsurface soil and groundwater conditions within the site with two exploratory borings, each roughly 30 feet deep, usinS a portable drill rig. The drill rig was subcontracted by NGA. 3. Map the slope and evaluate current slope stability conditions. NELSON GEOTECHNICAL ASSOCIATES, INC. �a�