101 E MARINE VIEW DR SEPA 018 - 011 Geotech Report 2025-04-15

Geotechnical Engineering Evaluation NGA File No.988017 East Marine View Drive Warehouse May 19,2017 Everett,Washington Page 5 Subgrade preparation in pavement areas should consist of overexcavating the pavement areas by a minimum of 18-inches and replacing with a minimum 18-inches of crushed rock. The base of the overexcavation should be covered with a non-woven fabric overlain by a Tensar TX 160 geogrid prior to the placement of the crushed rock layer. The soils that are expected to be encountered during site development are considered highly moisture- sensitive and will disturb in wet conditions. We recommend that the site be developed during the dry season. If construction takes place during the rainy months, the site soils may disturb and become extremely difficult to work. Also, if construction takes place during the wet season, additional expenses and delays should be expected. Additional expenses could include the need for placing a blanket of rock spalls on exposed subgrades, construction traffic areas,and pavement areas prior to placing structural fill. Erosion Control The erosion hazard for the on-site soils is considered slight for exposed soils but actual erosion potential will be dependent on how the site is graded and how water is allowed to concentrate. Best Management Practices (BMPs) should be used to control erosion. Areas disturbed during construction should be protected from erosion. Erosion control measures may include diverting surface water away from the stripped or disturbed areas. Silt fences or straw bales should be erected to prevent muddy water from leaving the site. Disturbed areas should be planted as soon as practical and the vegetation should be maintained until it is established. The erosion potential of areas not stripped of vegetation should be low. Temporary and Permanent Slopes 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 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 nature and condition of the cut slopes, and able to monitor the subsurface materials and groundwater conditions encountered. 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. NELSON GEOTECHNICAL ASSOCIATES, INC.