考虑温度影响的岩土材料高阶屈服函数

A high order yield function for geo-materials considering the effect of temperature

为了探究温度对土体剪胀特性和屈服面的影响,在临界状态土力学的框架下提出一个新的高阶剪胀方程。该高阶剪胀方程引入2个与温度相关的材料参数,对其进行积分可以得到一个新的高阶屈服函数以描述岩土材料屈服面的几何特性,而剑桥模型和修正剑桥模型的屈服函数可以视为其特例;进一步,考虑温度对土体前期固结应力的影响,可以得到一个新的考虑温度影响的屈服函数。将计算结果与试验结果进行对比分析,结果表明,升高温度会导致土体的塑性剪胀因子逐渐减小,同时土体的温度加载也会逐渐收缩。所给出的高阶剪胀方程及考虑温度影响的屈服函数对于不同温度下土体的剪胀特性和屈服面均有着良好的描述效果,为进一步探究温度对土体力学特性的影响规律和建立相应的弹塑性本构模型提供一个新的思路。

A high order dilatancy equation for considering the effect of the temperature on the dilatancy behaviors of clays is presented in the framework of critical state mechanics. Two material parameters related to the temperature are introduced in the dilatancy equation. Integrating the high order dilatancy equation will lead to a new yield function which is flexible to represent the experimental data of clays,and yield functions of the original and modified cam clay models can be regarded as the special cases of the new yield surface. Considering the influence of the temperature on the pre-consolidation pressure of clays,a new yield surface was obtained. Comparisons between the prediction results and the experimental datum were performed,and a good agreement between them was observed. It is shown that increasing temperature will lead to the yield surface of clays shrinking and,at the same time,the plastic dilatancy factor will decrease gradually. The proposed high order dilatancy equation and the yield surface related to the temperature can show an insight into the thermodynamic behavior of clays.