Charts for estimating strength parameters from slips in homogeneous slopes

摘要

When the slope geometry, unit weight and pore water pressure distribution in a homogeneous soil slope are given, the location of the critical slip surface for a particular method of slices is related only to the ratio of c' (cohesion) and tan φ' (internal friction angle). To utilize this relationship in back calculating c' and φ' values, two slope models with circular slip mechanism are presented to represent shear failures in simple fill or cut slopes and long natural slopes, and for each of the models, two dimensionless parameters regarding c'/tan φ' and maximum depth of the critical slip surface are introduced. Based on the new findings from limit equilibrium analysis of slope models, charts are plotted to show the relationships of the two dimensionless parameters and φ' values for a safety factor of unity. Using the charts can make a rapid estimate of the magnitude of both c' and φ' from a known position of the failure surface in a homogeneous slope.