离层水害是近年来我国东西部矿井较为常见且严重的水害类型,研究采动覆岩结构演化对 揭示离层突水机理、灾害预测防治有着重要意义。 为分析不同工程地质条件下离层突水演化机理, 将可以产生采动覆岩离层涌水的离层水体及其上下位一定范围的岩层统称为“突水离层带”。 建 立“突水离层带”采动岩体结构力学模型,根据上位岩层和下位隔水层破断规律,分析 5 种突水类 型(采动覆岩离层静水压突水、采动覆岩离层动力突水、多煤层叠加开采离层突水、传统顶板导水 裂隙涌水和离层积水不突水)的形成机制和力学条件,研究回采期间导水裂隙带时空演化与离层 突水的关系;基于工作面开采条件、覆岩条件、突水离层带发育位置和微震监测,分析了离层突水形 成条件,揭示了离层突水演化机理,并对永陇矿区崔木煤矿和招贤煤矿工作面开展了实例分析,提 出了工作面离层突水预报方法。 研究得出:1 随着工作面推进,充水离层上位岩层和下位隔水层 破断规律的差异是导致出现 5 种突水类型的根本原因;2 只有在采高 M 和充水离层与煤层间距 H 处于某种特定关系下,才会满足形成“突水离层带”的基本条件,发生离层突水;3 陕西崔木煤矿 21306 工作面离层突水主要是由上位岩层破断导致,突水期间高能量矿震(>104 J)发生次数增多, 微震日总能量和平均每次能量显著升高;而陕西招贤煤矿 1304 工作面离层突水是由下位隔水层破 断导致,突水期间<103 J矿震每日次数显著增多,对应矿震每日总次数升高而平均每次能量值减小。

Water inrush from the separation layers of overlying strata, as a common but severe hydraulic disaster, occurs frequently in the eastern and western mines of China in recent years. The evolution of mining overburden structure is of great significance to reveal the mechanism of water inrush from separation layers and to predict and prevent the disaster. To reveal the evolution mechanism of water inrush from separation layers in different engineering geological condi- tions, the composite strata related to water inrush from separation layers, involving the upper strata, water-filled separa- tion layers and the lower water-resisting layers, are collectively referred to as “Water-inrushing Separation Zone, WSZ for abbreviation”. The structural mechanical model of the WSZ causing water inrush was established. According to the different factors affected by the breaking laws of upper strata and lower water-resisting layers, the formation mech- anism and mechanical conditions of five types of roof water inrush, including hydrostatic water inrush, dynamic water inrush, water inrush induced by multiple coal seam superimposed mining, water flowing through water-conducting frac- tures and no water inrush from separated layer, were analyzed. Furthermore, the temporal and spatial evolution of the water-conducting fractured zone and the water inrush from the separation layers during mining was studied. Based on the mining conditions of working face, overburden conditions, the position of the WSZ, and microseismic monitoring, the formation conditions of water inrush from the separation layers were analyzed, and the evolution mecha- nism was revealed. Additionally, the working faces of the Cuimu colliery and the Zhaoxian colliery in Shaanxi Province were analyzed as case studies, and the prediction method of water inrush from the separation layers of working faces was proposed. The results show that the five types of water inrush are essentially related to the breaking law of the WSZ un- der the action of different water pressures and the supporting forces from the underlying strata with the face advance. The statistical data indicates that only with a certain relation between the mining height (M) and the distance of the WSZ to coal seam (H), the basic conditions of the WSZ can be satisfied. On the basis of the mechanical criterion of the WSZ, the water inrush from the separation layers in the working face 21306 of the Cuimu colliery is caused by the fractured upper strata. During the water inrush, the frequency of microseismic events whose energy is more than 104 J in- creased, and the total energy and average energy per day increased significantly. Whereas, the water inrush of the work- ing face 1304 of the Zhaoxian colliery was caused by the fractured lower water-resisting layer. During the water inrush, the frequency of microseismic events whose energy is less than 103 J increased, and the corresponding total num- ber of microseismic events increased significantly while the average energy per day decreased.