岩体结构面直剪力学行为的颗粒流分析

Numerical Simulation of the Shear Mechanical Behavior of Rock Discontinuity During Direct Shear Test with Particle Flow Code

采用颗粒流程序重点研究了岩体结构面直剪力学行为,分析了粘结解绑法和光滑节理接触法模拟结构面剪切力学行为的可行性。颗粒的尺寸和位置随机分布会引入一定的粗糙度,进而造成粘结解绑法结构面剪切过程中产生非实际的应力集中现象;结构面两侧颗粒在剪切过程中容易穿越结构面而引起颗粒间接触模型的不合理设置,使得光滑节理接触法结构面产生非实际应力集中现象,采用结构面相交接触判别法和结构面两侧颗粒组接触判别法解决光滑节理接触法存在的弊端。通过摩擦角为57°的岩体平直结构面在法向应力为3 MPa、5 MPa和7 MPa的直剪模拟与理论值对比分析,验证了结构面两侧颗粒组接触判别法能够真实模拟岩体结构面剪切力学行为的结论。

In this paper,the shear mechanical behavior of rock discontinuity during direct shear test was studied by using Particle Flow Code.The feasibility of bond-debonding method and smooth-joint contact method to simulate the shear mechanical behavior of planar discontinuity was analyzed.The random distribution of particle size and position introduces some micro-roughness,which causes the non-actual stress concentration during the shear process using bond-debonding method.Particles on both sides of discontinuity are prone to cross the discontinuity during shearing,the unreasonable setting of contact type leads to non-actual stress concentration on the discontinuity with smooth-joint contact method.Therefore,it is proposed to adopt the discrimination method of contact and discontinuity intersection,and the discrimination method of particle groups on both sides of discontinuity,to overcome the disadvantages of smooth-joint contact method.Finally,through the direct shear test simulation of planer discontinuity with the friction angle of 57°under normal stress 3,5,and 7 MPa,the feasibility of the discrimination method of particle groups on both sides of discontinuity was verified.