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本文介绍了三轴压缩下花岗岩试件内阶梯形错动面凸起部位破裂过程和失稳型式的实验。结果显示,当差应力量值(σ_1—σ_3)达到0.15—0.17(σ_1—σ_3)。(试件发生首次粘滑时的峰值应力)时,在阶梯形凸起的底部发生宏观破裂,其应力—位移关系呈线性变化,且破裂随应力量值的增加而继续扩展。在(σ_1-σ_3)≥0.3(σ_1-σ_3)c时,发生破裂贯通,凸起被剪断。断裂面上次级凹凸体发育。当(σ_1-σ_3)(?)(σ_1-σ_3)c时,原阶梯形错动面被铲平,其后沿该面发生了伴随大应力降和强烈振动的突发性失稳。上述结果表明,在断层滑动过程中,断层面上的凹凸体破裂直至被铲平的过程仅能导致微震、前震和声发射等事件的发生,而主震则系由平直断裂的粘滑引起的。
In this paper, the experiment of rupture process and instability type of the convex part of stepped trapezoidal surface in granite specimen under triaxial compression is introduced. The results show that when the magnitude of differential stress (σ_1-σ_3) reaches 0.15-0.17 (σ_1-σ_3). (Peak stress at the first stick-slip test), the macroscopic rupture occurs at the bottom of the step-shaped bumps, the stress-displacement relationship changes linearly, and the rupture continues to expand as the amount of stress increases. At (σ_1 -σ_3) ≥0.3 (σ_1-σ_3) c, rupture is penetrated and the protrusion is cut. Secondary asperities develop on the fracture surface. When (σ_1 -σ_3) (?) (Σ_1-σ_3) c, the original trapezoidal misalignment plane is leveled, followed by sudden buckling along the plane with large stress drop and strong vibration. The above results show that the rupture of the asperity on the fault plane until the process of being leveled can only lead to the occurrence of microseismic, pre-seismic and acoustic emission events during the fault slip, while the main shock is caused by the stick-slip of straight fracture of.