基于三维形貌参数的岩石节理峰值剪切强度模型研究

Research on Peak Shear Strength Model of Rock Joints Based on Three-dimensional Shape Parameters

基于Grasselli提出的节理粗糙度参数,通过揭示3种粗糙度参数表征视倾角的分布规律,分析了粗糙度参数和初始剪胀角和折减函数的关系,优化剪胀角模型中粗糙度参数的形式;通过文献对比分析,突出了岩石抗拉强度对节理抗剪强度的影响。采用法向应力、抗拉强度和节理粗糙度参数,提出了一种负指数形式的节理峰值抗剪强度新模型。最后通过73组试验数据和反算JRC值验证新模型准确度,并与经典模型对比。结果表明Gasselli模型和Tang模型在各自的试验数据中准确度较高,新模型和Xia模型误差较低,但新模型波动较小。新模型对Grasselli模型、Xia模型、Tang模型中存在的不符合摩尔库伦准则、物理含义不清晰、剪胀角边界条件不正确、未体现粗糙度等问题进行了改进。

Using the joint roughness parameters proposed by Grasselli,by revealing how the three roughness parameters represent the apparent inclination angle content,the relationship between the roughness parameters and the peak dilatancy angle is analyzed,and the use of roughness parameters in the dilatancy angle is optimized.The influence of rock tensile strength on shear strength of joints is highlighted by comparative analysis of literature.Finally,normal stress,tensile strength and joint roughness are used to define a new model of peak shear strength in negative exponential form.The accuracy of the new model was verified through the test data of 73 groups and the inverse JRC value,and compared with the results of the classic model.The results showed that the Gasselli model and the Tang model were more accurate in their respective test data.The new model and the Xia model have low errors,but Xia model fluctuates more than the new model.In the Grasselli model,the Xia model,and the Tang model,there are problems such as non-compliance with Moore Coulomb′s criterion,unclear physical meaning,incorrect boundary conditions of dilatancy angle,and failure to reflect roughness.The new model has been improved.