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5  Lambe and Whitman, Soils Mechanics, SI Version, 1979.  Hunt, Geotechnical Engineering Investigation Manual, McGraw-Hill, New York, 1984.  Bell, Engineering Properties of Soils and Rocks, Butterworth-Heinemann, Oxford, UK, 1992.  Duncan and Wright, Soil Strength and Slope Stability, John Wiley & Sons, 2005.  U.S. Dept. of the Interior, Bureau of Reclamation, Design of Small Dams, Third Edition, 1987. Table 5-1 in this reference provides typical values for compacted embankment soils.  USSD, Materials for Embankment Dams, January 2011. Typical Loading Conditions After the slope geometry, phreatic surface, and material properties estimates have been established, the potential loading conditions of the embankment should be evaluated. Typical loading conditions include:  Steady-state Drained – This condition represents the stability of the dam under normal operating conditions with steady-state seepage conditions and is one of the fundamental analyses performed in any quantitative analysis. Drained parameters should be used. Laboratory tests to evaluate the drained shear strength could include consolidated undrained triaxial tests with pore pressure measurement (CU’), drained triaxial tests (CD), or direct shear tests. Pore pressures can be estimated using flow nets, empirical relationships, or other types of seepage analyses. Both internal pore pressures (downstream slope) and external water pressures (upstream slope) should be included in the analysis. In case of noncohesive, drained embankment shell materials, infinite slope formulations (“angle of repose analysis”) could be used to analyze shallow failure surfaces.  End of Construction – This case should be analyzed when either embankment or foundation soils (or both) are predicted to develop significant pore pressures during embankment construction (undrained conditions) and undrained strengths are estimated to be less than drained strengths. Factors determining the likelihood of this occurring include the height of the planned embankment, the speed of construction, the saturated consistency of foundation soils, and others. If the materials are free-draining, the drained shear strengths should be considered. If the soils are cohesive, then undrained shear strengths should be considered. The total stress undrained shear strength should be evaluated, and laboratory tests to evaluate this could include undrained unconsolidated triaxial shear tests (UU). In the case of soft clay foundation, this loading case should be analyzed first, since it will likely control the embankment design.  Rapid Drawdown – Analyze the stability of the upstream embankment slope for the condition created by a rapid drawdown of the water level in the reservoir from the normal full reservoir level. Although there are several methods of analyses, each having a different method of modeling the phreatic pressures during a rapid drawdown condition, the three- stage method presented by Duncan et al for developing appropriate phreatic and pore pressure parameters is the authors’ recommended approach. Different agencies also have different requirements for the assumed drawdown elevations of the pool. For rapid drawdown analysis, undrained shear strengths should be used for both noncohesive (if material is judge to behave undrained as discussed above) and for cohesive embankment soils. Laboratory test to estimate undrained strengths could include the isotropically undrained triaxial tests with pore pressure measurement (CU’).  Seismic – Dams requiring seismic analysis should be designed to withstand at least the predicted earthquake loads with a full reservoir under steady-state seepage conditions. This is often referred to as a “pseudo-static” or post-earthquake analysis. Typically, this loading condition applies to high hazard structures. Refer to the applicable state