1610 SE EVERETT MALL WAY Geotech Report 2022-10-25

Subsurface Exploration, Geologic Hazard, and Krebs Property Preliminary Geotechnical Engineering Report Everett, Washington Preliminary Design Recommendations into two rocks of the underlying rock course. After setting each rock course, all voids between the rocks should be chinked on the back with quarry rock to eliminate any void sufficient to pass a 2-inch square probe. Individual tiers of the rockery should be limited to 8 feet in height. E) The rockery should include a drain consisting of rigid, perforated, PVC pipe fully enveloped in a 12-inch-wide, washed pea gravel trench that is placed behind the lower course of rock to remove water and prevent the buildup of hydrostatic pressure behind the rockery. The remainder of the rockery backfill should consist of quarry spalls with a maximum size of 4 inches and a minimum size of 2 inches. This material should be placed to a 12-inch minimum thickness between the back of the rockery and the cut slope. The backfill material should be placed in lifts to an elevation approximately 6 inches below the top of each course of rocks as they are placed, until the uppermost course is placed. Any backfill material falling onto the bearing surface of a rock course should be removed before the setting of the next course. F) Any asphalt paving should be sloped to drain away from the rockery. In addition, the areas above rockeries should be revegetated as soon as possible after rockery construction to reduce erosion. G) The gradient of the cut slope immediately behind the rockery, as well as that of the rockery face, should not exceed 6H:1V. A schematic rockery detail is provided in Figure 3. Construction of the rockery, including evaluation of subgrade and cut slope conditions, should be observed by AESI to confirm that construction conforms with our recommendations. Rockeries should not be used to face unreinforced fill slopes greater than 3 feet in height. If rockery facing of fill slopes greater than 3 feet in height is planned, the fill should consist of geogrid-reinforced structural fill. Design of a geogrid-reinforced fill for this purpose was not included in our current scope of work, but such a design could be provided by AESI upon the request of the client. 15M PROJECT DESIGN AND CONSTRUCTION MONITORING Our recommendations are preliminary in that construction details have not been finalized at the time of this report. We are available to provide additional geotechnical consultation as the project design develops and possibly changes from that upon which this report is based. If significant changes in grading are made, we recommend that AESI perform a geotechnical February 13, 2007 ASSOCIATED EARTH SCIENCES, INC. TJP/Id-KE070023A1-Projects{200700231KE1WP Page 15