固液耦合模式下含断层缺陷煤层回采诱发底板损伤及断层活化突水机制研究

Mechanism of water inrush due to damage of floor and fault activation induced by mining coal seam with fault defects under fluid-solid coupling mode

针对具体地质条件,以现场试验数据为基础,采用相似材料试验及数值模拟相结合的分析方法,对含断层缺陷煤层回采过程中底板损伤破坏及断层活化规律进行研究,研究得出:采用内径不同的水管能够很好地反映底板岩层渗透性的空间差异性,通过采用调节注水管水柱高度的方式可以控制水压以满足设计要求;煤层埋深、承压水水压及断层落差越大越易突水,断层防水煤柱宽度越大越不易突水;通过试验及模拟计算再现了不同因素影响下煤层回采过程中底板采动裂隙形成、断层活化到突水通道形成的全过程,揭示了含断层构造底板突水通道的形成机制;研究结果对承压水上含断层缺陷煤层回采时防水煤柱的留设具有重要的参考价值。

Based on the field test data, the damage and fracturing of the mine floor and the pattern of fault activation during the backstopping of the working face are evaluated by the combined method of similar material tests and numerical simulations. Some conclusions are drawn that the spatial differences of the permeability of the rock stratum floor can be simulated by water pipes with different inner diameters; the water pressure can be modulated by adjusting the height of the water column in the water pipe to meet the design requirements; a higher burial depth of the coal stratum, confined water pressure and throw of the fault promote more chances for water-inrush, while a larger width of the water-resistant coal pillar at the fault helps avoid water-inrush events; and the physical tests and numerical calculations are used to simulate the complete process of the formation of cracks at the floor due to mining, fault activation and formation of water-inrush channel during backstopping, and the mechanism of formation of the water-inrush channel at the floor fault structure is revealed. The conclusions provide significant references for the design of water resistant coal pillar during backstopping of the coal stratum above the confined water with fault defects.