基于变形元件的节理岩体压缩损伤本构模型

A compression damage constitutive model of jointed rock mass based on deformation components

为研究节理岩体在压缩荷载作用下的力学响应，基于岩体结构力学观点，把节理岩体在压缩荷载作用下的变形视为岩块变形与节理面变形的叠加，分别采用基于统计损伤模型的弹性损伤变形元件和考虑节理面闭合及滑动的变形元件计算岩块和节理面在压缩荷载作用下的变形，进而建立相应的节理岩体压缩损伤本构模型。并利用该模型讨论节理面弹性模量、最大闭合应变及剪切刚度等对计算结果的影响规律。最后利用该模型对含单条贯通节理的岩体在压缩荷载作用下的应力-应变曲线进行分析计算。研究结果表明：对于可能沿节理面发生剪切滑移的岩体而言，节理面剪切刚度对计算结果的影响最为显著。对本算例而言节理岩体的峰值强度仅为完整岩体的51.5%，反映节理对岩体强度的弱化效应。同时利用该模型得出岩体强度随节理倾角呈现出抛物线变化规律，即当节理倾角在50°~60°之间时，岩体强度最低，该结论与目前的理论及试验研究结果相吻合，从而说明该模型的合理性。

In order to study the mechanical response of the jointed rock mass under compression load, the deformation of jointed rock mass under compression load was regarded as the summation of rock block deformation and joint face deformation according to the viewpoint of rock structure mechanics. And the deformation laws of rock block and joint face under compression load were described with the elastic damage deformation component based on the statistical damage model and the joint closure and slippage deformation component, respectively. Then, the corresponding compression damage constitutive model of the jointed rock mass was established. The effect laws of such joint parameters as elastic modulus, maximum closure strain and shear stiffness on the calculation results were discussed with this model. Finally, the stress-strain curve of the rock mass with one single continuous joint under compression load was calculated with this model. The results show that the effect of the joint shear stiffness on the calculation results is the largest to the rock mass which can possibly slip along the joint face. The climax strength of jointed rock mass in this calculation example is only 51.5% of intact rock, which perfectly reflects the deterioration effect of the joint on rock mass strength. Meanwhile, the parabola change law of rock mass strength with the joint dip angle is obtained with this model, which shows that the rock mass strength is minimum when the joint dip angle is between 50°-60°. This conclusion fits very well with the current experimental and theoretical results, which indicates the rationality of this model.