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基于连续损伤力学理论及冻土横观各向同性损伤变量的计算方法,利用冻土常规三轴剪切试验,系统分析了不同温度、含水率和围压条件下冻结重塑黏土的损伤特性。研究结果表明:①不同试验条件下冻结重塑黏土损伤演化曲线规律一致,前期增长比较快速,后期变化相对平缓,且最大轴向损伤变量1max D一般介于0.6~0.8之间;②温度对冻结重塑黏土损伤特性影响较明显,降低温度可以明显强化冻土结构,减少冻土结构的损伤及延缓冻土损伤的发展,而含水率和围压对其影响不明显;③割线模量可以较好地表征冻土在加载过程中裂缝的发展特点和结构的损伤演化规律,损伤初始点轴向应变和割线模量与温度之间存在较好的线性增长关系,且冻结重塑黏土损伤应变门槛值0一般介于0.3%~0.7%,对应的割线模量一般介于200~550 MPa。
Based on the theory of continuous damage mechanics and the calculation method of transversely isotropic damage variables in frozen soils, the damage characteristics of the frozen remolded clay under different temperature, moisture content and confining pressure were systematically analyzed by the conventional triaxial shear tests of frozen soil. The results show that: (1) The damage evolution curves of frozen clay are the same under different experimental conditions, with rapid growth in the early stage and relatively slow changes in the late stage. The maximum axial damage variable 1max D is generally between 0.6 and 0.8. (2) The damage characteristics of remolded clay are more obvious. Decreasing the temperature can obviously strengthen the structure of frozen soil, reduce the damage of frozen soil structure and slow the development of frozen soil damage, while the influence of moisture content and confining pressure is not obvious. ③ The secant modulus can Better characterize the development characteristics of fractures and damage evolution of the structure during the loading process of the frozen soil, and there is a good linear relationship between the axial strain and the secant modulus at the initial damage point and the temperature, and freeze the clay damage The strain threshold 0 is generally between 0.3% and 0.7%, and the corresponding secant modulus is generally between 200 and 550 MPa.