近距离上行卸压开采间隔层损伤破裂演化及稳定性评价理论

In deep mining, such dynamic disasters as rock burst, coal and gas bump are getting more and more hazardous. Ascending mining is an effective approach for relieving high stress. The stability of inter-layer is a key problem for ascending mining. This project aims at the goal to investigate the mechanical stable criteria of inter-layer which influenced by up and down twice mining actions. The innovative works are needed to research: (1)Scan the micro-structure of rock by SEM, design an experiment by combining digital speckle correlation method, sonic wave test, and MTS815 servo-test system as a integer,in order to modify the Hoek-Brown failure criteria by using sonic wave velocity and fractal dimension of fissures. The modification can satisfy the damage evolution of large scale strata affected by multi-mining actions.(2)Investigate the failure distribution and gradation within the inter-layer affected by up and down twice mining actions,especially obtain the new failure increment affected by the up mining action.(3) Set a mechanical damage model for analysing the stability of inter-layer as well as for recognizating the key strata, by considering strata mechanical properties,mining depth, mining height, mining region, twice mining actions, and so on, in order to obtain a criteria for estimating an optimal thickness of inter-layer which can satisfy both effective relieving stress and keeping inter-layer in a stable state.The research will overcome the shortcoming of determining inter-layer thickness based on mining-coefficient adopted widely at home and abroad, and will supply a theoritcal support for safe and scientific deep mining in our country.

随着开采深度增加，冲击地压、煤与瓦斯突出等动力灾害日趋严重。实践表明，上行卸压开采是有效防治动力灾害的手段，而间隔层稳定性是上行卸压开采安全的关键问题之一。本项目以受上下两次采动影响间隔层稳定性评价为目标，拟开展如下创新性研究工作：(1)在对岩石细观结构SEM扫描基础上，进行数字散斑、声波测试与MTS815伺服系统同步试验，采用声波速度和裂隙分形特征修正Hoek-Brown准则，并用于研究煤矿大范围岩层受多次采动影响损伤破坏演化规律；(2)揭示上下煤层两次采动影响下间隔层内破裂分布及梯度变化规律，特别是上部二次采动导致新增破裂分布；(3)考虑岩层力学性质、采深、采高、开采范围、上下两次采动等因素，建立间隔层损伤破裂演化力学模型并提出稳定性力学条件，获得满足有效卸压与间隔层稳定并举的厚度力学判据。本项目将突破国内外基于采动影响系数来确定间隔层厚度的现状,为深部科学上行卸压开采提供理论支持。