10105 19TH AVE SE Geotech Report 2018-01-02 MF Import

� r . � , �. . � � Geotechnical Engineering Evaluation Everett Vcterinary Clinic February 21, 2002 NGA File No. 342902 r Page 5 r Seismic Potential 1 The project site is located within Zone 3 of the Seismic Zone Map shown as Figure 16-2 of the 1997 Uniform Building Code(UBC). This correspoRds to a Seismic Zone Factor,Z, of 0.30. We recommend I thet the subsurface soils be considered Soil Profile Type S�,as described in the UBC. ( Harards assceiated with seismic activity include liquefaction potential and amplification of ground motion. Liquefaction is caus�;d by a rise in pore pressures in a loose sand deposit beneath the ground � i� water table. The medium dense to dense, glacial till soils that are interpreted to underlie the site have a low potential for liquefaction or amplification of ground motion. � I CONCLUSIONS AND RECOMMENDATIONS I General It is our opinion that the site is compatible. f:om a geotechnical standpoint, with the planned development. The underlying medium dense to dense native glacial soils should provide ade��uate I- support for the planned stnicwre. Foundntions for ttx: st�vcture should exlend through any topsoil or loose soils and bear on the underlying medium dense to deuse r lacial till soils or structural fill suppo�ted I-- on these soils. Medium dense native soils were encountered ro:cghly between 1 and 3 feet below tF� existing surface elevation at the Icxations of our explorations. ' Shallow perched ground water was encounte��ed in the majority of our stibsurFace explorations. We Iexpect the amount of this perched water to decrease during the dry season. Ho:vever, project budget and scheduling should nllow for additional effcsrts to control ground water if encoun:erod in structure or utility Iexcavations. We huve provided preliminary recommendations for ground wate� :-�ntrol in the Site Drainage subsection of this report. We understand that a detention ponG is planned at the east side of the site. The design for ihis vond has not been completed. We recommend that grading in the pond area and fill placement and compection be performed in accordance with the recommendations found in the Site Preparation and Gradiog a�d � Structural FIII subsections of this report. Silty, low-permeability fill liner should be used inside the pond � or a synthetic liner could be ��ed. We recommend that the interior sides of the pond have an inclination I no sreeper than 3H:1V. We should be retained to review detention pond design and provide specific ' I recommendntions for pond liner and pond installation. I NELSON GEOTECHNICAL ASSOC/ATES, INC � � ,1