动静组合加载下不同负温人工冻结粉质黏土强度和变形特性分析

研究动静组合加载下不同负温冻土的强度和变形特性对提高冻土开挖破碎效率、确保冻土工程稳定具有重要的理论和工程意义.借助改进的分离式Hopkinson压杆试验系统,研究了不同负温下人工冻结粉质黏土的静态和动态应力-应变曲线、抗压强度、变形模量和破坏特征.试验结果表明:单轴动态压缩条件下,随着试验温度的降低,人工冻结粉质黏土...

Strength of artificially frozen silty clay with different negative temperatures under dynamic and static combined loading and deformation characteristic analysis

Studying strength and deformation characteristics of frozen soil with different negative temperatures under dynamic and static combined loading is of important theoretical and engineering significance for improving excavation and crushing efficiency of frozen soil and ensuring the stability of frozen soil engineering.Here,with help of the improved separated Hopkinson compression bar test system,static and dynamic stress-strain curves,compressive strength,deformation modulus and failure characteristics of artificially frozen silty clay under different negative temperatures were studied.The test results showed that under condition of uniaxial dynamic compression,with decrease in test temperature,the proportion of elastic segment of artificial frozen silty clay stress-strain curve decreases,and the dropping segment after peak tends to be obvious;under 3-D dynamic and static combined loading,stress-strain curves of frozen soil with different negative temperatures can be divided into 3 stages of elastic one,plastic one and failure one;the temperature sensitivity of artificially frozen silty clay under impact load is stronger than that under static load to reflect the dynamic brittleness of frozen soil;under impact load,the temperature sensitivity of frozen soil in 3-D dynamic and static combined state is weaker than that in uniaxial state;under action of dynamic uniaxial load,all frozen soil samples with different negative temperatures reveal crushing failure,while under 3-D dynamic and static combined loading,frozen soil has no obvious cracks after failure.