基于统计损伤理论的冻土蠕变本构模型研究

Frozen Soil Creep Model Based on Statistical Damage Theory

假定冻土粘塑性微元损伤符合修进的莫尔-库仑准则,损伤变量服从Weibull随机概型分布;基于热力学原理和统计损伤理论,通过推导得到了相关联流动法则下的蠕变损伤耦合本构方程。为了便于研究冻土蠕变和损伤的耦合作用,将提出的本构模型,通过用户子程序嵌入到有限元程序中。最后,对冻土中桩基承载力模型试验进行了数值模拟,结果表明:基于统计损伤理论的冻土蠕变本构模型能较好的模拟冻土蠕变变形的全过程,并且与实测蠕变变形十分吻合,该模型对冻土结构物长期稳定性分析和工程预测具有重要参考意义。

A new form of frozen soil micro-unit strength is discussed following the improved Mohr-Coulomb criterion,under Weibull random distribution. Based on thermodynamic and statistical damage theory, The constitutive relationship of the viscoelastic plastic damage-coupling constitutive function with plastic normality flow rule is deduced. The viscoelastic plastic damage-coupling constitutive model for geo-materials is embedded into the commercial software ADINA. Combining pile modle testing in frozen soil and numerical simulations, the final fiting curves and calculation indicate that the theoretical results coincide with the experimental ones very well.