异形充填节理剪切破坏宏细观机理及强度模型

Macroscopic and mesoscopic mechanisms of shear failure of irregular filling joints and its strength model

为探究异形充填节理面在剪切过程中的宏细观行为,本文基于二维颗粒流程序PFC 2D生成9种上下面不同粗糙度的充填节理面组合并进行模拟。研究结果表明:异形充填节理面宏观破坏过程中,首先是充填物两侧发生局部破坏,随后节理边缘开始出现裂隙,最后是充填物与节理之间的黏结面发生破坏;细观破坏过程中,首先是两侧颗粒发生移动,中间颗粒由于充填物的黏结作用,位移较小,但随着剪切进行,黏结面发生破坏,试件内部颗粒位移差逐渐消失,表现为上部试件整体位移。模拟过程中异形充填节理面峰值剪切强度受两侧节理面粗糙度影响,呈现出粗糙度越接近强度越高的规律。通过简化模型改进了一种新型充填节理面峰值剪切强度公式,为下一步的研究提供了理论基础。

In order to study the macroscopic and mesoscopic behaviors of the irregular filling joints during the shearing process,nine kinds of upper and lower joints of different roughness were generated and simulated by the two-dimensional particle flow program PFC 2D.The results showed that in the process of macro-damage of deformed filling joint surface,the local damage firstly occurs on both sides of the filling,then cracks began to appear on the joint edge,and finally,the bonding surface between the filling and the joint was damaged.In the process of meso-scale failure,firstly,the particles on both sides moved,and the displacement of the intermediate particles was small due to the bonding effect of the filler.However,as the bonding surface is destroyed by shearing,the displacement difference of the particles inside the specimen gradually disappeared,showing the overall displacement of the upper specimen.The peak shear strength of the special-shaped filling joint surface was affected by the roughness of the joint surfaces on both sides during the simulation process,showing the rule that the roughness was closer to the strength.A new formula for peak shear strength of filled joint surface was improved by simplifying the model,which provided a theoretical basis for further research.