Plastic strain characteristics on frozen silty clay subjected to intermittent vehicle loads

Abstract

The plastic strain of frozen soil is a key parameter in evaluating the stability of embankment in cold regions. In practical engineering, the vehicle loading is an intermittent cyclic load due to a period of no-load between adjacent vehicles. At this study, a series of dynamic tests were carried out at −3.0℃, and the effects of intermittent ratio (γ), cyclic stress ratio (CSR), frequency (f) and vibration (N) were considered. The results show that the cumulative plastic strain of frozen silty clay increases nonlinearly with increasing vibrations, and with the increase in intermittent ratio it decreases nonlinearly. There exists a critical intermittent ratio, when the intermittent ratio exceeds the critical one, the cumulative plastic strain with a given vibration will keep constant. As the cyclic stress ratio rises, the cumulative plastic strain also grows in nonlinear. For γ ≠ 0.0, the cumulative plastic strain differences slowly tend to stabilize with a CSR value of over 0.7, and for γ = 0.0 the strain difference obviously rises. With increasing frequencies, the cumulative plastic strain decreases in a nonlinear way, and the cumulative plastic strain difference increases and decreases linearly at γ = 0.0 and γ = 1.0, respectively. Finally, a cumulative plastic strain model, considering γ, CSR, f and N, is established. The reliability of model is also verified by comparing the calculated results with the measured ones. This study can provide a reference for predicting the cumulative plastic strain of frozen silty clay under the intermittent vehicle loads in cold regions.