2824 GRAND AVE NAUTICA CONDOMINIUMS 2018-01-02 MF Import

GEOTECHNICAL ENGINEERING STUDY Cascasia Pacific Properties, Ltd. July 15, 1999 E-8602 Page 8 Cantilevered shoring should be designed to resist the active earth pressures imposed by an equivalent fluid with a unit weight of thirty-five (35) pounds per cubic foot (pcf). This lateral earth pressure value assumes a horizontal backfill, no surcharges, and drainage behind the wall is provided. Where applicable, the construction of temporary slopes above the shoring can be considered for purposes of reducing the height of the shoring. Temporary slopes constructed above the proposed temporary shoring will impart higher lateral earth pressures on the shoring. For preliminary design, an equivalent fluid pressure of forty-five (45) pcf can be used wnere temporary slopes inclined at 1.5H:1V (Horizontal:Vertical) are constructed above the shoring. ECI can provide additional recommendations to account for sloping conditions above the shoring, as necessary, when the proposed slope heights and slope geometries are determined. Where applicable, surcharge loading from adjacent structures, vehicles, or any other load source should be included in the shoring design. Surcharges from adjacent roadways or buildings should be considered if the load source is within a horizontal distance equal to the excavation depth. To account for traffic surcharge loads, a two foot soil surcharge should be added to the temporary shoring wall design, where applicable. Passive pressure acting along the embedded portion of the soldier piles may be used to resist active earth pressures and surcharge loading. The passive earth pressure can be calculated using an equivalent fluid with a unit weight of four hundred (400) pcf. The upper two feet of the embedded portion of the soldier pile, however, should be neglected when calculating passive resistance. The equivalent fluid pressure value for calculating passive resistance includes a factor -of -safety of 1.5. The passive resistance can be applied to two times the diameter of the soldier piles. Mobilization of full passive pressure assumes that the excavation bottom is horizontal for at least four times the depth of the soldier pile embedment. ECI should be contacted to provide appropriate design values if sloping conditions are present along the excavation bottom. A typical pressure distribution for a temporary cantilever wall design is shown on Plate 3. For design of timber lagging, a one-half reduction in the recommended active earth Pressures can be assumed to account for soil arching. The shoring should be backfilled with a free draining sand or gravel. If necessary, lean mix can be used to backfill along the upper four feet of lagging to help confine the retained soils behind the shoring wall during the lagging installation. Large sloughs that develop behind the shoring wall during the lagging installation can be repaired by injecting lean mix through the lagging and into the sloughed area. E.�h tM.