三向应力下裂隙岩石力学特性试验研究

Mechanical Characters and Failure Mechanism of Fracture Rock Under Triaxial Loading

通过三轴压缩试验,对预制张开裂隙岩样在不同围压下裂隙参数(裂隙倾角、裂隙长度)对岩样的强度和变形破坏特征的影响规律进行了研究,并对裂隙岩样的破坏机制进行了探讨。结果表明:1)在围压相同、倾角相同条件下,裂纹长度对峰值强度的影响较大,裂纹越长,其峰值强度越小,而裂隙倾角对岩样峰值强度影响不大;2)裂隙岩样残余强度阶段的粘聚力下降严重,说明残余强度阶段试件已形成宏观贯通的裂缝,其承载力主要由裂隙面间的摩擦力承担;3)预制裂隙岩体的弹性模量随围压的增加经历了先减少再增加的非线性变化。

Triaxial compression test was carried out in order to analyze the influence of strength and deformation with different fissure angle and length under different confining pressures and discuss failure mechanism of jointed rock. The results show that there was great effect of the crack length on the peak strength with same confining pressures and fissure angle, the peak intensity decreased with the increasing of the crack length, hut the crack angle had little impact on the peak strength~ the cohesive force dropped seriously during the residual strength phase of crack rock that indicated the specimens had formed the macro transfixion crack, in this case, the friction of the fracture surface beared the hearing ca-pacity; elastic modulus presented nonlinear that first showed a decrease and later an increase.