岩体节理非线性法向循环加载本构模型的改进

Improvement of Nonlinear Constitutive Model for Rock Fractures under Normal Cyclic Loading

假定卸载曲线和重加载曲线在法向的起始刚度由前一次加载曲线和卸载曲线决定,从而完全确定岩体节理循环加载本构方程.对模型参数的不同取值,将已有的不同模型统一起来,通过卸载曲线渐近线内移的方式来反映滞回特性.将改进的节理弹性非线性法向变形本构模型拓展到循环加、卸载条件下,考虑节理面几何特性、充填物特性及岩石类型的复杂性,在将节理变形的非线性程度定量化描述的同时,修正以往模型对曲线形式做出硬性假定的方式.新模型的预测结果与试验结果吻合良好,验证了模型的可行性.

It is supposed that the initial normal stiffness of unloading and reloading curves is calculated from those of the previous loading and unloading curves, and then the cyclic loading constitutive equation for rock fracture is established. With different values of the parameters, this model generalizes the existing different models. By moving inward the asymptote of unloading curves, the characteristic of hysteresis is reflected. Describing the extent of nonlinearity quantitatively, the improved nonlinear elastic constitutive model for normal deformation of rock fractures is extended to cyclic loading process, which changes the way that the assumption is made by the kind of the stress-deformation curves in previous models made. Considering the geometric characters, infill mineralogy of the rock fractures and the rock types, the predication results fitted the test results well in adopting the new model for the predication of others test data, which verifies the feasibility of the new model.