Pore Pressure Increment-Strength Reduction Limit Analysis Method for Saturated Rock and Soil Slope

Now, on the basis of hydrostatic pressure difference of overall stress method, the fluid-solid coupling analysis of saturated slope by strength reduction limit analysis method is realized by adjusting soaking surface and using the action of levitating force, but the changing of pore pressure in the process of strength reduction is not resolved. In this paper, the asynchronous load transfer process on the solid skeleton and free water of soil-rock was explained from the relations of the strength parameters of solid phase (c,φ) and the strength parameters of liquid phase (pore water pressure). The effective stress strength reduction limit analysis method and the approximate determination method of pore pressure increment were advanced, and the pore pressure increment-strength reduction limit analysis method was realized on the basis of hydrostatic pressure difference of overall stress method. The research shows that zero-pore pressure surface increase 0.34~0.44 m(4%~5%) than the safety factors of strength reduction limit analysis method, this is close to the empirical value (0.5 m) that was used in the fluid-solid coupling analysis of saturated slope.