利用分离式Hopkinson压杆试验装置,进行了冻结黏土在单轴与主动围压两种状态下的动态冲击压缩试验,对比分析了单轴与主动围压状态下冻结黏土的动态应力-应变曲线、动态抗压强度和破坏模式。研究结果表明,单轴状态下,温度为-15 ℃时,动态应力-应变曲线可分为弹性阶段、塑性阶段和破坏阶段。主动围压状态下,-5 ℃和-15 ℃的动态应力-应变曲线可分为弹性阶段、塑性阶段和破坏阶段。在相同应变率和冻结温度的条件下,主动围压状态下冻结黏土的动态抗压强度均高于无围压状态,动态抗压强度随着主动围压的增加而增大。当冻结温度和围压相同的条件下,动态抗压强度随应变率的提高而增大。单轴状态下,温度为-5 ℃时,冻结黏土呈塑性破坏,温度为-15 ℃时,冻结黏土呈脆性破坏。
The dynamic impact test under uniaxial loading and confining pressure states of artificial frozen clay have been carried out by splitting Hopkinson pressure bar equipment. The dynamic stress-strain curves, the dynamic compressive strength and failure modes of artificial frozen clay under two experiment conditions have been analyzed. The result shows that under uniaxial loading state at -15 ℃, the dynamic stress-strain curves can be divided into three stages: elastic stage, plastic stage and failure stage. Under confining pressure state, the dynamic stress-strain curves can be divided into three stages: elastic stage, plastic stage and failure stage at -5 ℃ and -15 ℃. At the same strain rate and freezing temperature, the dynamic compressive strength under confining pressure state is larger than that in uniaxial loading state, and it exhibits the positive confining pressure and strain rate sensitivity. Under uniaxial loading state, the failure modes are plastic failure and brittle failure for artificial frozen clay at -5 ℃ and -15 ℃, respectively.