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GeoTest Services, Inc. March 17, 2022 <br />4320 Thomson Avenue, Everett, WA Project No. 22-0285 <br />OMANNISENOLIM <br />Passive earth pressures that develop against the sides of building foundations, in conjunction <br />with friction developed between the base of the footings and the supporting subgrade, will resist <br />lateral loads transmitted from the structure to its foundation. For design purposes, the passive <br />resistance of well -compacted fill placed against the sides of foundations is equivalent to a fluid <br />with a density of 350 pcf. The recommended value includes a safety factor of about 1.5 and is <br />based on the assumption that the ground surface adjacent to the structure is level in the direction <br />of movement for a distance equal to or greater than twice the embedment depth. The <br />recommended value also assumes drained conditions that will prevent the buildup of hydrostatic <br />pressure in the compacted fill. Retaining walls should include a drain system constructed in <br />general accordance with the recommendations presented in the Foundation and Site Drainage <br />section of this report. In design computations, the upper 12 inches of passive resistance should <br />be neglected if the soil is not covered by floor slabs or pavement. If future plans call for the <br />removal of the soil providing resistance, the passive resistance should not be considered. <br />An allowable coefficient of base friction of 0.35, applied to vertical dead loads only, may be used <br />between the underlying imported granular structural fill and the base of the footing. If <br />foundations will bear directly on the native soil, an allowable coefficient of 0.30 should be used. <br />If passive and frictional resistance are considered together, one half the recommended passive <br />soil resistance value should be used since larger strains are required to mobilize the passive soil <br />resistance as compared to frictional resistance. A safety factor of about 1.5 is included in the base <br />friction design value. GeoTest does not recommend increasing the coefficient of friction to resist <br />seismic or wind loads. <br />Retaining Wall/Shoring Wall Parameters <br />It should be noted that GeoTest has been contracted solely to provide our opinions regarding the <br />soil parameters at the planned wall location along the eastern and southeastern boundaries of <br />the project limits. These provided parameters do not and are not intended to constitute a wall <br />design. GeoTest understands that a soldier -pile shoring wall with shotcrete lagging is planned for <br />the southwest portion of the house excavation. Please be aware that soil parameters can change <br />with location, disturbance, configuration, and drainage conditions. GeoTest is available to <br />provide additional consultation during the wall design process. <br />The following parameters shown in Table 1 can be assumed for the design of the proposed wall. <br />GeoTest can provide additional wall recommendations once the preliminary drawings are <br />completed and/or upon request. <br />0 <br />