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• experienced geotechnical engineer. Undisturbed block samples are Shelby tubes should be extracted from <br />relevant soil strata. Disturbed samples should also be extracted for general laboratory index testing. <br />Additional "in-situ" tests should be performed with field torvanes, penevometers and nuclear densometers. <br />A preliminary soil laboratory testing plan should consist of the following: <br />• Classification <br />• Moisture content <br />• Specific gravity <br />• Consolidation <br />• Unconfined compression <br />• Consolidated undrained triaxial shear [es[ with pore water pressure measurements. <br />This program may be modified according to [he results of the field investigations and types of soils <br />encountered. <br />The objective of these investigations will be to define the extent and location of the failure surface of the <br />slide and determine the properties and characteristics of the slope that will be used in the stability models. <br />3.0 ANALYSES <br />Slope stability analyses should be completed with the computer program SLOPFJW. SLOPE/W computes <br />factors of safety for two-dimensional slopes with the slices methods of analysis, allowing several models of <br />soil shear strength properties and pore-water pressure conditions. The slope conditions would be modeled <br />according to the topography of the area prior to and after the failure, groundwater and moisture conditions <br />of the soil mass, and shear strength properties of the soils obtained from the site investigations detailed in <br />• the previous section. Back analyses would be performed bazed on the configuration of the shde to verify <br />the model. <br />Subsequent slope stability analyses would be performed for each of the slide stabilization methods <br />identified as part of the following section. <br />4.0 SLOPE STABII.IZATION METHODS <br />Alternative slope stabilization methods should be proposed based on the results of the site investigations <br />and analyses performed az part of the previous sections. A static factor of safety of 1.3 should be used az <br />the criteria to design and implement the preferred stabilization method (or combination of several <br />methods). This factor of safety assumes that the properties of the soils used in the designs ate well known <br />and supported by the laboratory testing presented in Section 2.0. <br />Some of the slope stabilization alternatives that may be proposed for this caze are detailed as follows. <br />• Slope Flattening <br />Slopes may be regraded to an appropriate angle determined from the stability analyses. <br />Intermediate benches may also be included to reduce the average slope. This alternative would <br />probably require moving the existing road further up the slope. Unstable soil mass would be <br />removed and recompacted. <br />Toe reinforcement <br />Compacted soils with high shear strength and permeability may be placed at the toe of the slide. <br />• The extent and size of the reinforcement would be determined from the stability analyses. <br />