非共面闭合裂隙巴西圆盘试验与颗粒流模拟研究

An experiment and particle flow study of Brazilian disk containing two non-coplanar filled fissures

天然裂隙岩体抗拉强度及破裂模式是岩体重要的力学特性,在一定程度上影响岩体的稳定.鉴于此,使用室内试验和数值模拟的方法探究了平行非共面闭合双裂隙岩桥倾角对巴西试样的抗拉强度和破裂模式的影响.结果表明:1)试样的抗拉强度随岩桥倾角的增大呈现先减小后增大的规律,且随着岩桥倾角增大试样的最终破裂模式受到预制裂隙的影响越大;2)Flatjoint模型中有效接触模量主要影响试样的弹模,黏结力与抗拉强度比主要影响试样的拉压强度比,并提出关于单轴压缩和巴西劈裂试验细观参数验证的一般过程;3)使用Smoothjoint模拟了闭合裂隙巴西试样,模拟结果与试验结果吻合较好,试样的破裂模式主要受到黏结力的分布影响;4)岩桥倾角在30°~60°时黏结力随加载的进行不断向试样中心聚集,而倾角在90°~120°时试样黏结力主要集中在裂纹的尖端,这是造成试样承载能力不同的主要原因.

Tensile strength and failure mode are important mechanical properties of natural fractured rock mass,and have effect on rock stability in a certain extent.Therefore,experiment and numerical simulation were conducted to investigate the effect of ligament angle on tensile strength and failure mode of Brazilian disk containing non-coplanar filled fissures.The investigated conclusions can be described as follows.1）With the increase of the ligament angle,the tensile strength first decreases and then increases,and the filled fissures have greater influence on the failure modes;2）the effective modulus in Flatjoint model mainly affects the elastic modulus of the specimen,and the ratio between bond cohesion strength and tensile strength mainly affects the UCS/TS ratio.Then a new calibration procedure is proposed for the uniaxial compression and Brazilian test;3）The Smoothjoint model is used to simulate the filled fissure.The simulation results are in good agreement with the experimental results,and the failure modes are dominated by the FJ-force field;4）The FJ-force continues to gather to the sample center whenβis in the range of 30°to 60°,and concentrates at the crack tip whenβis in therange of 90°to 120°,which is the reason that the specimens have different capacity.