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Introduction
Theoretical_Background
Method of Slices
Bishop
Spencer
Morgenstern & Price
Use of Limit Equilibrium
Choice of Geometry
Strengths & Pressures
Long Term Problems
Short Term Problems
Summary
References
Input Instructions
Geometry
Boundary Forces
Pore Pressures
Strength Parameters
Earthquake Loading
Iteration Control
M-P Method
Convergence
Examples
Example 1
Example 2
Example 3i
Example 3ii
Example 4
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For the effective stress analysis we can show the excess pore pressures at large strains in terms of the effective normal stress at consolidation and the
or Kc ratio, in the same way we showed the undrained shear strength in example 3ii. The curves below were reduced from the same set of data as were the undrained strengths shown in example 3ii, therefore the two sets of reduced data are consistent.
For the post-earthquake stability analysis the excess pore pressures are determined for each slice as a function of the normal stresses at consolidation. The excess pore pressures are added to static pore pressures giving the total pore pressure at the base of each slice as shown below.
The CU triaxial test data used in this example, and in example 3 was obtained from static undrained tests which followed a prior undrained cyclic loading. Therefore the strength data may be more applicable to the post-earthquake analysis than to the rapid-drawdown analysis. For dilatant materials the excess pore pressures at large strains and the undrained strengths are generally independent of the initial pore pressures prior to the static undrained loading, therefore it is reasonable to use the same data for both examples.
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