岩石节理峰值抗剪强度新模型

A new peak shear strength model of rock joints

Grasselli提出的形貌参数充分反映了节理表面粗糙度的三维特征,Xia模型、Yang模型、Tang模型采用Grasselli提出的三维形貌参数,但Xia模型峰值抗剪强度公式不满足边界条件,Yang模型材料项不能反映节理剪切受拉破坏机制,Tang模型预测精度较低且剪胀角与法向应力关系未能体现粗糙度参数的作用,文中提出一个新的峰值抗剪强度公式弥补了上述各模型的不足之处。根据Grasselli、唐志成等、Yang等发表的63组数据对新模型进行验算,结果表明,Tang模型预测精度较低,新模型和Xia模型、Grasselli模型预测精度较为接近。此外发现,关系函数f(sn)考虑形貌参数的作用时可以有效地提高模型的预测精度。新模型公式形式较为简洁、物理意义明确、符合摩尔-库仑准则、量纲统一,可以为相关的工程研究提供参考。

The morphology parameters proposed by Grasselli fully described the three-dimensional roughness of rock joints. Based on Grasselli’s three-dimensional parameters, Xia et al, Yang et al, and Tang et al developed new peak shear strength models. It is revealed that Xia’s model didn’t agree well with the boundary conditions. Yang’s model can not explain the mechanism of tensile failure during the shearing of rock joints. Tang’s model showed a low accuracy in predicting the peak shear strength of a rock joint. In light of these problems, a new peak shear strength model is established. The new model is verified based on the 63 groups of rock joints published by Grasselli, Tang and Yang, the results show that the new model has the same accuracy with the published model, and the new model is simple in terms of form so it can provide a reference for rock engineering. Besides, it will improve the accuracy in predicting the peak shear strength between the calculated results and the test results when the relationship function f(?n) takes the morphological parameter into consideration.