4945 OCEAN AVE 2018-01-02 MF Import

GEOTECHNICAL ENGINEERING STUDY Mr. Rick Remsing E-10558 May 5, 2003 Page 9 Liquefaction Liquefaction is a phenomenon in which soils lose all shear strength for short periods of time during an earthquake. Ground;haking of sufficient duration results in the loss of grain to grain contact and rapid increase in pore water pressure, causing the soil to behave as a fluid. To have a potential for liquefaction, a soil must be cohesionless with a grain size distribution of a specified range (generally sands and silt); it dust be loose to medium dense; it must be below the groundwater table; and it must be subject to sufficient magnitude and duration of groundshaking. The effects of liquefaction may be large total and/or differential settlement for structures founded in the liquefying soils. Based on the density of the site soils, it is ECI's opinion the potential for liquefaction over the site during a seismic event is negligible. Ground Motion Response In accordance with Table 16-J of the 1997 UBC, soil type Sc should be used in design. Excavations and Slopes The following information is provided solely as a service to our client. Under no circumstances should this information be interpreted to mean that ECI is assuming responsibility for construction site safety or the contractor's activities; such responsibility is not being implied and should not be inferred. In no case should excavation slopes be greater than the limits specified in local, state and Federal safety regulations. Based on the information obtained from the field exploration and laboratory testing, the native sand soils would be classified as Type C by OSHA. Temporary cuts greater than four feet in height in Type C soils should be sloped at an inclination of 1.51-1:1 V (Horizontal:Vertical). The dense silt native soil would be classified as Type A by OSHA. In Type A soils temporary cuts greater than four feet in height can be steepened to 3/4H:1 V. If slopes of this inclination, or flatter, cannot be constiLcted, temporary shoring may be necessary. Shoring will help protect against slope or excavation collapse, and will provide protection to workers in the excavation. If temporary shoring is required, we will be available to provide shoring design criteria. Earth Consultants, Inc.