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 III. PRELIMINARY DESIGN RECOMMENDATIONS 7.0 INTRODUCTION Our exploration indicates that, from a geotechnical standpoint, the parcel is suitable for the proposed development provided the recommendations contained herein are properly followed. The foundation bearing stratum is relatively shallow, and conventional spread footing foundations may be utilized. 8.0 SITE PREPARATION 8.1 Clearing and Stripping Site preparation of the planned building and pavement areas should include removal of all trees, brush, debris, and any other deleterious materials. These unsuitable materials should be properly disposed of off-site. Additionally, any areas of organic topsoil should be removed and the remaining roots grubbed. Areas where loose surficial soils exist due to grubbing operations should be considered as fill to the depth of disturbance and treated as subsequently recommended for structural fill placement. Any buried utilities should be removed or relocated if they are under building areas. The resulting depressions should be backfilled with structural fill, as discussed under the Structural Fill section of this report. All fill soils below footing areas should be stripped down to the underlying, medium dense to very dense natural sediments. 8.2 Pavement Subgrade Preparation After stripping of the organic topsoil layer and removal of roots, we recommend that the soil exposed in the proposed driveway areas be recompacted to a firm and unyielding condition using a 20-ton (minimum) vibratory roller. The recompacted area should then be proof-rolled with a fully loaded tandem-axle dump truck. Any soft or yielding areas identified during proof-rolling should be overexcavated and backfilled with structural fill. 8.3 Temporary and Permanent Cut Slopes In our opinion, stable temporary construction slopes should be the responsibility of the contractor and should be determined during construction. For estimating purposes, however, we anticipate that temporary, unsupported cut slopes, or utility trenches greater than 4 feet in height or depth, completed within the unsaturated, loose to medium dense existing fill or weathered lodgement till sediments can be planned at a maximum slope of 1.5H:1V (Horizontal:Vertical). Similarly, unsupported cut slopes or utility trenches completed within February 13, 2007 ASSOCIATED EARTH SCIENCES,INC. TJ 1'11d-KE070023A1-Projecu1200700231KEIWP Page 8