中主应力对岩石变形局部化的影响

岩石局部化变形在水利、石油、核废料处理、二氧化碳地质储存以及工程地质和岩土工程中都具有很强的实际意义,为了研究中主应力对于岩石局部化变形的影响,本文把轴对称拉伸和压缩状态的变形带角属性选做边界条件,推导得到RR模型中的本构参数,最后预测得到其他应力状态的变形带角,与Dunham白云岩真三轴实验数据进行比较,发现中主应力对岩石强度、变形率以及变形带角都有影响;变形带角在最小压应力值固定的情况下,随着平均应力的增加而增加,随着最小压应力的增加而减小,与认为中主应力对岩石强度以及变形没有影响的摩尔库伦条件预测结果不同.

Study on localized deformation of rocks considering effects of intermediate principal stress

The research on deformation localization in rocks has practical significance in oil, water conservancy, disposal of nuclear wastes, underground sequestration of CO₂, Engineering Geology and Geotechnical Engineering. In order to study it, Rudnicik and Rice(1975) refined the theory of bifurcation approach of Plastic Mechanics and established a RR constitutive model. Taking the data from axisymmetric test on Dunham-Dolomite rocks by Mogi as the boundary conditions to infer the constitutive parameters of RR model, then the band angle of the other stress state is predicedt, which is compared with the result of Mohr-Coulomb condition and RR theory. It is found tha the intermediate principal stress plays a role in the failure process of rocks. Based on the calculation result, the band angle tends to increase with increasing mean stress for fixed values of the least compressive stress and decrease with increasing values of the least compressive stress. These phenomena contradict with Mohr-Coulomb condition which predicts that the intermediate stress has no effect on rock strength and deformation.