考虑围压效应的修正软岩热弹黏塑性本构模型

 大量的软岩三轴剪切试验表明，不同的围压下，软岩力学特性变化非常大。随着围压的增加，软岩的应变软化和剪胀性变弱；当围压足够大时，甚至表现为应变硬化和剪缩。已有软岩热弹黏塑性本构模型针对不同的围压大小，需要设定不一样的参数，使其应用到数值分析上带来一定困难。为了能用统一参数来描述软岩受围压影响的力学性质，对已有的软岩热黏弹塑性本构模型进行修正。修正模型中所有参数都具有明确的物理意义且都可通过常规三轴试验确定。通过实验数据与计算结果对比，验证了修正本构模型的正确性。

A modified thermo-elasto-viscoplastic constitutive model for soft rock considering the effect of confining stress

Large amount of triaxial shear experimental evidences show that the mechanical behaviour of soft rock is dependent on the confining stress. The strain softening and shear dilation of soft rock were reduced with the increase of the confining stress. When the confining stress is large enough，the strain hardening and shear contraction occur. The original thermo-elasto-viscoplastic model for soft rock has different parameters for different confining stresses and is therefore difficult to be applied to engineering problems. In order to describe the mechanical behaviour of soft rock with one set of parameters，the original constitutive model was modified to consider the confining stress dependence. The parameters of the modified model have explicit physical meanings and can be determined from triaxial tests. The accuracy of the modified model was verified by comparing with the simulated results and experimental data.