用屈服与断裂配合模型对冻土力学行为的分析

Analysis on the Mechanical Behavior of the Frozen Soil by Means of the Model of Material Yielding and Fracture

为了对冻土实验研究中出现的各种现象给出符合力学原理的解释,提出一种屈服与断裂相配合的含裂纹材料模型。该模型在通常的连续介质模型中考虑了实际材料存在缺陷的因素。屈服的表征借助塑性力学的极限原理,断裂的表达应用了断裂力学中应力强度因子概念和断裂韧度的概念。先对各种常见影响因素进行分类,将影响因素分为强化性因素与软化性因素,再根据材料的一般特性研究两类因素对配合图上临界曲线所呈现的影响规律,最后应用模型分析得到的一般规律对冻土实验研究结果进行力学分析。本模型可以简明地给出材料失效的规律性,不仅可以进行线性化的单调变化趋势的分析,还可以进行非线性的极值变化趋势的分析。既可用于对已有试验结果的解释,也可进行影响因素的预测分析。

To offer the explanations to the phenomena in the frozen soil test compliant with the mechanical principle, a model of material yielding and fracture has been put forward. This model takes into account the defects in the factual material in the continuum model. Yielding is based on the limit principle of plastic mechanics and fracture on the fracture mechanics. First, the affecting factors have been classified into two groups of strength group and soften group. Then the rules of each factor group＇s impact on the marginal curves on the model charts have been studied. In the end, the results of frozen soil experiments have been analyzed by means of mechanics. It is different from other material models in that the model offers the failure rule concisely and clearly, which is not only applied to the monotonous analysis on linear trend of material variation, but also applied to the nonlinear analysis of the extreme strength value. It is used not only to explain the results obtained from the experiments, but also to predict the results to be tested.