This paper analyzes the strain stability during mining, which often causes a water inrush. Mining couses costant stress on the fault zone, which is a loading process on the system composed of fault material and surrounding medium. A cusp catastrophe model is presented and the necessary and sufficient conditions leading to fault systems are discussed. The fault zone is assumed to be planar and is a combination of two media: medium-1 is elastic-brittle or strain-hardening and medium-2 is strain-softening. The shear stress-strain constitutive model for the strain-softening medium is described by the Weibull’s distribution law. It was found that the instability of a fault system mainly relies on the ratio between the stiffness of medium1 to the post-peak stiffness of the strain-softening medium, and the homogeneity index of strain-softening medium and the bifurcation point, k ≤ 1, which is the turning point of the fault system from stability to potential instability. One can judge the occurrence of fault instability from this feature and regard the index D as a parameter, which reflects the precursory abnormality of a fault.

中文翻译：

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断层系统引起顶板突水的稳定性机理

本文分析了采矿过程中的应变稳定性，这往往会引起突水。采矿对断层带产生持续应力，是对断层物质和周围介质构成的系统的加载过程。提出了尖点突变模型，并讨论了导致故障系统的充分必要条件。假定断层带是平面的，是两种介质的组合：介质 1 是弹性脆性或应变硬化，介质 2 是应变软化。应变软化介质的剪应力-应变本构模型由威布尔分布定律描述。发现断层系统的不稳定性主要取决于介质刚度与应变软化介质的峰后刚度之比，应变软化介质的均匀性指数和分岔点，k ≤ 1，这是故障系统从稳定到潜在不稳定的转折点。可以从这一特征判断故障不稳定的发生，以指标D为参数，反映故障的先兆异常。