1329 MADRONA AVE Geotech Report 2022-10-25

Subsurface Exploration,Geologic Hazard,and Janowicz Property Geotechnical Engineering Report Everett,Washington Preliminary Design Recommendations deeper excavations in these deposits will require shoring as recommended below. As is typical with earthwork operations,some sloughing and raveling may occur, and cut slopes may have to be adjusted in the field. Excavation cuts that encounter groundwater seepage will require flatter slope inclinations and/or groundwater seepage mitigation as described above. With respect to all temporary slope operations, WISHA/OSHA regulations should be followed at all times. Permanent slopes that will not be exposed to standing water can be designed with inclinations of 3H:1V or flatter, and otherwise should be faced with a retaining wall in accordance with recommendations in"Shoring," below. 9.4 Site Disturbance and Wet Weather Construction The on-site soils contain a high percentage of fine-grained material that makes them moisture- sensitive and subject to disturbance when wet. The contractor must use care during site preparation and excavation operations so that the underlying soils are not softened. If disturbance occurs,the softened soils should be removed and the area brought to grade with structural fill. if earthwork will be completed during winter months or "wet seasons" (typically October through April), we recommend budgeting to construct all structural fills with select, free-draining fill materials. Soils which are determined to be over optimum moisture content will require significant effort to scarify, aerate, and dry to reduce moisture content prior to compaction in structural fill applications. Care should be taken to seal all earthwork areas during mass grading at the end of each workday by grading all surfaces to drain and sealing them with a smooth-drum roller. Stockpiled soils should be covered whenever rain is possible. If wet season construction is expected, crushed rock fill could be used in the construction entrance and staging areas. The stripped subgrade should be observed by the geotechnical engineer, and should then be covered with a geotextile fabric, such as Mirafi 500X or equivalent. Once the fabric is placed, we recommend using a crushed rock fill layer at least 10 inches thick. 10.0 STRUCTURAL FILL AESi does not recommend placing fill within the building area so as to not increase loads on the slope. Where structural fill is required, such as may be for the driveway, the following recommendations shall apply and shall be subject to approval by the geotechnical engineer. All references to structural fill in this report refer to subgrade preparation,fill type, placement, and compaction of materials as discussed in this section. If a percentage of compaction is specified under another section of this report,the value given in that section should be used. May 1a,2018 ASSOCIATED EARTH SCIENCES,INC. NS/ld-170649E002-2-ProJects1 2 01 70649 1KE1WP Page 12