Slope Failure and the loss of controllability of the incremental response of a soil specimen subject to an arbitrary loading programme

摘要

An analysis of the instability conditions of slopes, based on the concept of latent instability, is presented first. It is shown that, for special conditions, multiple strain rate solutions are possible under the same loading increment. Drained and undrained cases for sand and clay slopes are considered. For rapid loading of sandy slopes, the latent instability analysis allows the reasons of catastrophic collapses of very flat slopes to be explained. Latent instability can occur even under more general loading programmes in the hardening regime, provided the flow rule is non-associate and the stiffness matrix is not positive-definite. Failures due to loss of load control in undrained tests or shear or compaction band occurrence in axisymmetric tests are examples.