软岩非线性蠕变模型研究

Study on nonlinear creep model of soft rock

以工程实际中广泛应用的元件组合模型为基础,通过引入损伤变量和硬化变量,建立了一个软岩非线性蠕变模型。分析认为,Maxwell体等价于一个线性损伤的虎克弹性体,Kelvin体相当于一个线性硬化的牛顿黏性体,Burgers体则是一个能同时描述线性损伤、硬化的模型。软岩蠕变过程中,其微观结构会发生变化,并导致软岩形变行为产生相应的改变,引入非线性损伤、硬化变量代替Burgers模型中的线性损伤、硬化变量,可以反映这种改变对软岩蠕变的影响。所建立的非线性蠕变模型可以用一个统一的方程描述软岩蠕变过程三个阶段的变形特征。将该模型与试验曲线进行对比,两者吻合较好。

Based on the component model, the damage and hardening variables were introduced into the creep model to express the nonlinear creep behavior of soft rock. A new nonlinear creep equation was established for soft rock. The Maxwell chains was equivalent to a linear damage Hooker body, the Kelvin chain was equivalent to a linear hardening Newton body, and the Burgers chain was a model describing linear damage and hardening for creep of rock. With the development of the creep of soft rock, the variation of rock microstructure had influence upon mechanical behavior. These changes were explained by nonlinear damage and hardening variables. The nonlinear creep model was established, which could describe three phases of soft rock creep. The results of model agreed with those of test perfectly.