An Approach to the Problem of Progressive Failure

Abstract

In this paper, the different factors that contribute to progressive failure are briefly reviewed, and the necessary conditions for its occurrence delineated.Experiments on specimens trimmed from block samples of several clays were performed to study the post-peak stress deformation behavior. It is shown that the stiffness of the testing system has an important influence on the post-peak characteristics. A method of obtaining the effective 'residual' angle of friction from drained triaxial tests is developed.Because of the localization of deformation in the failure zone, both in the laboratory and in the field, the laboratory nominal post-peak stress–strain relationship cannot be directly applied to field problems. Based on laboratory and field observations on the mechanism of deformation, the ratio of the shear modulus of the failure zone to that of the pre-peak range is proposed as a deformation parameter to be used in analysis of progressive failure.A simplified theory for the solution of the problem of progressive failure is then developed, and a case record of a first time slide in sensitive Leda clay is analyzed to illustrate the practical application of the approach.