冻结黏土动态力学特性的SHPB试验研究

通过使用分离式霍普金森压杆（Split Hopkinson Pressure Bar,简称SHPB）动力学试验,系统研究了不同应变率、不同温度和不同含水率条件下冻结黏土的动态力学特性,获得了冻结黏土的动态应力-应变关系以及相关冻土动力学参数的变化规律。试验结果表明：冻土具有明显温度效应和应变率效应,随着应变率的增加和温度的降低,冻土破坏过程从塑性破坏逐渐转变为脆性破坏。在冲击荷载作用下,冻土的动态应力-应变关系曲线随加载应变率的不同呈现3种典型曲线,冻土的最大应变与且仅与应变率呈线性递增规律；单一因素影响下,冻土的动强度、动弹性模量均随应变率的增大、温度的降低和未超过饱和状态的含水率的增大而增加。

Dynamic characteristics of frozen clay by using SHPB tests

Based on the Split Hopkinson Pressure Bar (SHPB) tests, dynamic characteristics of frozen clay with various low temperatures and water contents at different strain rates are studied. Variations of dynamic parameters and dynamic stress-strain curves of frozen clay are obtained and analyzed. The results of SHPB tests show that the frozen clay exhibits temperature effect and strain rate effect, and that the failure type tends to change from plastic failure to brittle one with the increase of the strain rate or the decrease of the temperature. Under impact load, the frozen clay exhibits three typical dynamic stress-strain curves as the strain rate increases, and the maximum strain of the frozen clay only linearly increases with the strain rate. The increase of strain rate and water content () and the decrease of temperature result in an increase in both the dynamic strength and elastic modulus of the frozen clay considering the effect of a single factor.