节理面剪切过程中细观接触规律及JRC预测方法研究  

Study on prediction of joint roughness coefficient and meso-contact law in shear process of joint surface

作　　者：莫孙庆 皮桥辉[2] MO Sunqing;PI Qiaohui(Guangxi Infrastructure Investigation Co.,Ltd.,Guilin 541000,China;College of Earth Science,Guilin University of Technology,Guilin 541000,China)

机构地区：[1]广西基础勘察工程有限责任公司,广西桂林541000 [2]桂林理工大学地球科学学院,广西桂林541000

出　　处：《人民长江》2023年第5期218-222,230,共6页Yangtze River

基　　金：国家自然科学基金项目(52068016)。

摘　　要：研究岩石剪切机理是预测岩石节理抗剪强度的基础。利用数值追踪技术反演了节理面直剪试验过程中细观微凸体的接触分布规律,从接触角度、接触面积和接触位置入手,分析并建立了平均接触角与岩石节理面粗糙度系数(JRC)值关系式。研究表明:①从剪应力峰值时刻对应的平均接触角来看,法向应力对接触角影响并不显著,接触角与节理面的形貌有关。剪应力与平均接触角呈现正相关,剪应力最大时刻对应的平均接触角最大。②剪切过程中大多数(90%以上)剪切位置发生在微凸体迎着剪切方向的一侧,很小一部分接触区域发生在背离剪切方向的一侧。③利用平均接触角确定JRC值进而预测节理面强度精度较高,平均误差不到5%,证明利用接触角确定JRC值进而预测节理面抗剪强度具有一定的准确性与合理性。Studying the shear mechanism of rock mass is the foundation for predicting the shear strength of rock joints.The contact distribution law of micro convex body in the process of direct shear test of joint surface was inverted by numerical tracking technology.The contact angle,contact area and contact position were analyzed,and the relationship between the average contact angle and joint roughness coefficient(JRC)value was established.In this process,the following conclusions were obtained.①From the view of contact angle corresponding to peak shear stress,the influence of normal stress on the contact angle was not significant,and the contact angle was influenced by contact morphology.The shear stress was positively correlated with the average contact angle,and the average contact angle and the maximum shear stress both reached their largest at the same time.②During the shear process,most(more than 90%)shear positions occurred on the side of the micro convex facing towards the shear direction,and a little of contact area occurred on the side away from the shear direction.③Using the average contact angle to determine the JRC value and then predict the joint surface strength had a high accuracy,and the average error was less than 5%,showing satisfactory accuracy and rationality.

关 键 词：剪切 岩石节理 JRC值 三维扫描 抗剪强度 

分 类 号：TU[建筑科学]