A new back analysis of strength parameters from single slips

For a given homogeneous slope with an arbitrary geometry, unit weight and pore water pressure distribution, the position of a critical failure surface will remain unique for a specified value of c'/tan phi. Based on this theoretical relationship between c' and phi' and the critical slip surface, a straightforward back analysis method is proposed to estimate the magnitude of c'/tan phi' from a known position of the failure surface observed in the field slope. The back analysis of c'/tan phi' can easily be implemented by incorporating the method into existing limit equilibrium slope stability analysis software. When the c'/tan phi' value is obtained, a pair of c' and phi' can uniquely be determined by considering the fact that the factor of safety is equal to unity. (C) 2007 Elsevier Ltd. All rights reserved.