变幅循环荷载下胶凝砂砾石材料的动强度特性研究  

Dynamic Strength Characteristics of Cemented Sand and Gravel Material Under Variable Amplitude Cyclic Loading

作　　者：黄虎 熊衍来 曹克磊 张献才 HUANG Hu;XIONG Yan-lai;CAO Ke-lei;ZHANG Xian-cai(School of Water Conservancy,North China University of Water Resources and Electric Power,Zhengzhou 450046,China)

机构地区：[1]华北水利水电大学水利学院,河南郑州450046

出　　处：《水电能源科学》2023年第3期161-164,153,共5页Water Resources and Power

基　　金：河南省科技攻关项目(192102310224);国家自然科学基金项目(52109154)。

摘　　要：动强度是大坝稳定安全分析的重要参数,对工程设计具有重要意义。采用大型动三轴仪,开展变幅循环加卸载试验,探究了不同围压和水泥含量对胶凝砂砾石(CSG)材料动应力—动应变关系的影响;基于摩尔—库伦强度准则,以动应变为塑性内变量,研究了CSG材料在经历塑性变形时其动强度参数的演化规律。结果表明,动粘聚力和动内摩擦角随水泥含量增大而增加;随着动应变增加,动粘聚力下降较快,动内摩擦角增加,骨料间的剪切滑移产生的摩擦力起主导作用;达到峰值动应力时,骨料间的有效受力面明显减小,动粘聚力下降平缓,动内摩擦角减小,具有一定的滞后性。动粘聚力随动应变变化的规律符合幂函数关系;动内摩擦角与动应变变化的规律符合二次函数关系。研究结果可为CSG坝的抗震设计优化提供理论参考。Dynamic strength is an important parameter for dam stability and safety analysis, which is of great significance to engineering design. Variable amplitude cyclic loading and unloading test was carried out to explore the effect of different confining pressure and cement content on the dynamic stress-strain relationship of cemented sand gravel(CSG) material by large dynamic triaxial instrument. Based on the Mohr Coulomb strength criterion, the evolution law of dynamic strength parameters of CSG materials during plastic deformation was studied by taking the dynamic strain as the plastic internal variable. The results show that the dynamic cohesion and dynamic internal friction angle increase with the increase of cement content. As the dynamic strain increases, the dynamic cohesion decreases rapidly, the dynamic internal friction angle increases, and the friction force generated by the shear slip between the aggregates dominates. When the peak dynamic stress is reached, the effective stress surface between aggregates decreases obviously, the dynamic cohesion decreases gently, the dynamic internal friction angle decreases with a certain hysteresis. The law of dynamic cohesion with dynamic strain conforms to the power function relationship. The law of dynamic internal friction angle and dynamic strain change conforms to the quadratic function relationship. The research results can provide a theoretical reference for the optimization of seismic design of CSG dam.

关 键 词：胶凝砂砾石材料 变幅循环荷载 塑性阶段 动粘聚力 动内摩擦角 

分 类 号：TV43[水利工程—水工结构工程]