采动诱发断层活化导水试验研究

Experimental study on fault activation conducting water inrush

华北地区深部开采矿井,高地应力作用下煤层采动诱发断层活化引起的承压水突涌是矿井水害的主要形式之一,借助相似材料模拟试验台,通过自主设计的试验装置和试验方法,以五沟煤矿F13断层为工程背景,研究承压水上煤层开采的覆岩运动破坏形态、底板裂隙发育扩展特征、断层带应力和结构演化规律,再现断层活化导水全过程。以工作面距断层带的距离为时间参照,采动诱发断层活化导水存在4个明显阶段:断层带应力超限屈服、断层带拉裂延展、两盘错动滑移、承压水导升。以承压水沿断层带的导升高度为基准,寻找承压水导升高度的相关性因素:工作面距断层带的距离与导升高度近似呈负线性关系;水压力、断层带宽度与导升高度具有正相关性,试验过程中水压力与导升高度的相关性呈现强-弱-强的变化趋势;根据试验结果和规律设计断层防水煤柱宽度为40 m,现场观察未出现明显突漏水现象、效果良好。研究成果对于揭示断层活化突水机制、指导矿井防治水具有一定的意义。

The confined water inrush is typically caused by fault activation under high ground pressure due to coal mining. It is one of the main forms of water disaster in deep mining in North China. Based on the equipment of similar simulation tests, we designed the testing device and proposed the testing method. Fault F13 in Wugou mine was chosen as a geological background in this study. Then the overburden movement, the expansion characteristics of the bottom plate, the stress and structure evolutions of the fault zone and the whole process of the aquifer were investigated. Taken the mining distance as a time reference, the water inrush consists of four obvious stages： the yield of fault zone caused by over-stress, cracking and extending of the fault zone, diastrophism and slip of fault zone, rising of confined water. Based on the height of the pressurised water along the fault zone, its correlation factors were analysed. It was found that the relationship between the mining distance and confined water rise was an approximately negative liner. Moreover, the pressure of confined water showed positive correlations with the width of the fault zone and the height of confined water. In particular, the correlation between the pressure of confined water and the height of confined water exhibited a strong-weak-strong law during the whole experiments. According to the obtained experimental result, the waterproof coal pillar was designed as 40 m in the fault F13, and the no water leakage and inrush were found. This indicates that the designed height is reasonable. Therefore, this study can provide a useful reference to understand and prevent mining water disasters.