浅埋煤层保水开采隔水层稳定性的模拟研究

 隔水层稳定性是保水开采研究的关键。通过对黏土隔水层应力–应变全程曲线测定，建立以残余强度和应变为关键指标的模拟方法。采用变单因素分析法，考虑材料破坏的峰值强度、峰值应变及残余强度，获得黏土隔水层应力–应变全程相似的模拟材料和配比规律。以榆树湾煤矿条件为背景，开展保水开采岩层移动规律和隔水层稳定性的模拟，得出分层开采基岩关键层和隔水层的移动和垮落规律，揭示顶板淋水是基岩风化层裂隙水的机制，并得到实践验证。实验发现，基岩和隔水层在工作面后部存在主要下沉区，是最易形成导水裂隙带的区域。主要下沉区的下沉梯度Ts是隔水层稳定性控制的重要指标，合理增大下沉区间和减小下沉梯度是隔水层稳定性控制的有效途径。论证榆树湾煤矿保水开采的可行性，并为浅埋煤层保水开采控制提供借鉴。

SIMULATION OF CLAY AQUIFUGE STABILITY OF WATER CONSERVATION MINING IN SHALLOW-BURIED COAL SEAM

According to the complete stress-strain curve test of clay aquifuge，a new simulation method is put forward considering the peak strain and strength as well as residual strength and strain. Through series of material proportion tests by use of the single-factor analysis method，the aggregate materials and proper agent for materials are obtained；and the proper material proportions are advanced for the complete stress-strain simulation of clay aquifuge. Through the simulation tests of longwall mining of Yushuwan coalmine，the caving feature and subsidence movement of bedrock roof and clay aquifuge of overburden are presented. It is shown that the roof pouring water of mining face is from weathering layer rather than ground surface，which is proven by mining practice. It is also found that there is a main subsidence area behind mining face；and the clay aquifuge trends to lose stability in this area. The subsidence gradient Ts of this area is the key index for aquifuge stability control；and to decrease the Ts or increase the subsidence span is the effective approach of aquifuge stability control. This simulation shows that the water conservation mining can be realized in Yushuwan coalmine；and this research provides a method for water conservation mining in shallow-buried coal seam.