Abstract:

Based on the upper bound limit analysis theorem and the shear strength reduction technique, the equation for expressing the critical limit-equilibrium state was employed to define the safety factor and its corresponding critical failure mechanism for a given layered soft-rock slope by means of the kinematical approach of limit analysis theory. The definition of safety factor was adopted in the present method so that the results from the limit analysis can be applied to engineering practices directly. The case study and comparative analysis show that the solutions presented agree well with available predictions; and the validity of the analysis method could be illuminated. From the numerical results, it is also shown that the safety factor and the instability failure range of layered soft-rock slope are controlled by slope angle, bulk density, slope height, seismic effect coefficients and strata inclination; and when the strata inclination within a certain range, the instability probability of layered soft-rock slope reaches its maximum.

Key words: layered soft-rock slope, dynamic stability analysis, quasi-static analysis, safety factor, strength reduction method, upper- bound theorem of limit analysis