An investigation of the mechanisms which control soil behaviour at fast rates of displacement

摘要

The results of high displacement rate ring-shear tests are reported that show that pre-existing oriented shear surfaces in clay soils which mobilise residual strength at slow displacement rates evolve at high shear rates into zones of turbulent shear that mobilise critical state strength (the 'positive rate effect'). 'Negative rate effects' (in which the undrained residual strength is significantly less than the drained residual strength) can occur at very high displacement rates (1000mm/min) when free water has access to an undulating shear surface.