冻土-构筑物界面粘聚-损伤-摩擦本构模型

Cohesion-damage-friction constitutive model of the frozen soil-structure interface

冻土与构筑物界面本构模型对寒区工程的设计、分析和数值模拟至关重要.耦合粘聚损伤模型和摩擦模型建立了冻土与构筑物界面的一维本构模型.模型从界面的细观力学特征出发,考虑胶结冰在界面剪切过程中的力学响应及界面出现相对滑动后的摩擦力学特征,将界面微元区域分为损伤部分和非损伤部分进行分析.在界面发生相对位移的过程中,微元由非损伤向完全损伤过渡,其中非损伤部分假设为弹性变形,随着损伤的发展摩擦力逐渐发挥作用.基于界面的基本运动学假设得到了微元体损伤演化过程和摩擦演化过程,进而依据均匀化方法建立了界面的本构关系,模型中的参数物理意义明确且容易从试验数据中获取.数值结果表明模型对界面的应变软化型曲线和应变硬化型曲线都有较好的拟合效果,试验曲线中的关键参数在模型中都能够体现.

The constitutive model of the interface between frozen soil and structure is very important to the design,analysis and numerical simulation of engineering practice in cold regions.A one-dimensional constitutive model of the interface between frozen soil and structure was established by coupling the cohesive damage model and the friction model.Based on the meso-mechanical assumption,the mechanical response of cemented ice at the interface and the friction mobilization,the representative elementary area of the interface was divided into damaged part and non-damaged part.During the shearing of the interface,the non-damaged part of the representative elementary area was assumed to be elastic deformation.The friction effect was mobilized during the representative elementary area transform from the initial undamaged state to the fully damaged state.The damage evolution equation and the friction evolution process of the representative elementary area were established based on the basic kinematics hypotheses of the interface,and the constitutive relationship of the interface was established according to the homogenization method.The parameters in the model have clear physical meanings and are easy to obtain from the test data.The numerical results show that the model has a good fitting effect on the both strain softening curve and strain hardening curve of the interface,and the key parameters in the test curve can be reflected in the model.