8525 EVERGREEN WAY BURGER KING 2021-05-10

Geotechnical Engineering Evaluation NGA File No. 998317 Burger King Restaurant Development August 2,2017 Everett,Washington Page 7 Temporary and Permanent Slopes Specific grading plans were not available at the time this report was prepared. However, temporary cut slope stability is a function of many factors, including the type and consistency of soils, depth of the cut, surcharge loads adjacent to the excavation, length of time a cut remains open, and the presence of surface water or groundwater. It is exceedingly difficult under these variable conditions to estimate a stable, temporary, cut slope angle. Therefore, it should be the responsibility of the contractor to maintain safe slope configurations since they are continuously at the job site, able to observe the soil and groundwater conditions encountered,and able to monitor the nature and condition of the cut slopes. The following information is provided solely for the benefit of the owner and other design consultants and should not be construed to imply that Nelson Geotechnical Associates, Inc. assumes responsibility for job site safety. Job site safety is the sole responsibility of the project contractor. For planning purposes, we recommend that temporary cuts in the on-site soils be no steeper than 1.5 Horizontal to 1 Vertical (1.5H:1V). If significant groundwater seepage or surface water flow were encountered, we would expect that flatter inclinations would be necessary. We recommend that cut slopes be protected from erosion. The slope protection measures may include covering cut slopes with plastic sheeting and diverting surface runoff away from the top of cut slopes. We do not recommend vertical slopes for cuts deeper than four feet if worker access is necessary. We recommend that cut slope heights and inclinations conform to appropriate OSHA/WISHA regulations. Peuuanent cut and fill slopes should be no steeper than 2H:1 V. However, flatter inclinations may be required in areas where loose soils are encountered. Permanent slopes should be planted and the vegetative cover should be maintained until it is established. We should review plans and visit the site to evaluate excavations for this project. Foundation Support Conventional shallow spread foundations should be placed on undisturbed medium dense or better native glacial soils or be supported on structural fill extending to those soils. We encountered medium dense or better soils at approximately 2.0 to 3.0 feet below the existing ground surface in our explorations. Where undocumented fill or loose soils are exposed at the planned footing elevation, the subgrade should be over-excavated to expose suitable bearing soil. The over-excavation may be filled with structural fill, or the footing may be extended down to the native bearing soils. If footings are supported on structural fill, the fill zone should extend outside the edges of the footing a distance equal to one-half of the thickness of the structural fill below the footing. NELSON GEOTECHNICAL ASSOCIATES, INC.