基于三维形貌参数的偶合节理峰值抗剪强度公式

 节理表面形貌是影响节理峰值抗剪强度的重要因素，采用人工模拟材料节理分别在0.5，1.0，1.5，2.0，3.0 MPa的法向应力下进行直剪试验，研究三维形貌参数与峰值抗剪强度之间的关系。选用节理面有效三维平均倾角 、粗糙度系数 、最大可能接触面积比 作为表征节理面粗糙度的参数。直剪试验前、后采用TJXW–3D型便携式岩石表面形貌测量仪对节理表面进行形貌数据测试；根据直剪试验结果建立节理峰值剪胀角与三维形貌参数 ， ， 之间的关系；建议采用新的强度准则计算节理的峰值抗剪强度。新公式的计算结果与试验值具有较好的一致性，并将其与Barton公式的计算结果进行比较，可知Barton公式的计算结果低于试验实测值。

A NEW PEAK SHEAR STRENGTH FORMULA FOR MATCHING IRREGULAR JOINTS BASED ON 3D MORPHOLOGY PARAMETERS

Joint surface morphology is one of the most important factors for peak shear strength of jointed rock. Artificial joints are used for direct shear tests under five levels of normal stresses，i. e. 0.5，1.0，1.5，2.0，3.0 MPa，to study the relationship between 3D morphology parameters and peak shear strength. Effective joint surface 3D mean angle ，surface roughness coefficient and the maximum possible contact area ratio are selected to describe the joint roughness. Scanning joint surface after each direct shear tests by TJXW–3D topography scanner and the above selective morphology parameters are calculated. A new peak shear dilation angle model is proposed with relationship to 3D morphology parameters of ， ， . Then，a new strength criterion with three morphology parameters is suggested for modeling the peak shear strength of rock joints. A comparison between the proposed models and the experimental results show a relatively good agreement. At last，the calculated results by the new criterion is compared to the well-known Barton?s criterion. It is shown that Barton?s criterion underestimates the observed peak strength.