浅埋煤层高强度开采覆岩(土)破坏演化及溃沙控制技术

随着我国煤炭资源的大规模和高效开采，薄基岩浅埋深的矿区常发生切冒、抽冒、台阶下沉，造成水资源和环境破坏严重。但是，赋存于萨拉乌苏组含水层下伏的连续黏土层的存在，使得基岩及其黏土隔水层组合结构下采动破坏规律不同于传统的基岩岩层，这将为防治矿井突水和实现保水采煤提供了条件。论文采用数值模拟和理论分析的方法，模拟了“黏土隔水层-基岩风化带-基岩”结构特征下不同黏土层与基岩厚度条件下覆岩(土)裂隙发育、顶板破断运动的基本特征，获得了浅埋深条件下采动覆岩(土)的破坏变异规律与发育高度，分析了溃沙的致灾因素和预测判据，并据此提出防治突水溃砂的技术手段。研究结果表明：浅埋煤层“沙土基型”覆岩(土)结构条件下，由于不同基岩与土层厚度的控制作用，使得覆岩(土)破坏发育高度和特征产生变异；水砂源、通道、动力源和空间是近松散含水层溃砂的主要致灾因素，并提出了预测溃沙发生的判据；可通过防止顶板切冒、含水砂层水头压力疏降、局部注浆固沙和合理留设防砂(塌)煤岩柱等技术控制浅埋煤层溃砂灾害发生。

Failure characteristics of overburden rock (soil) and sand control technology in high strength mining of shallow coal seam

With the large-scale and efficient mining of coal resources in China,local caving and bench convergence accidents frequently occur in the mining area with thin bedrock and shallow depth,which cause serious water resources and environmental damage.However,the mining failure rules of bedrock and clay aquiclude combination structure are different to traditional rock strata because of continuous clay layer,which will provide conditions for the prevention and treatment of mine water inrush and water preserved mining.In this paper,the methods of numerical simulation and theoretical analysis were conducted to simulate the basic characteristics of overlying rock (soil) fracturing and roof breaking movement under the “clay aquifuge-bedrock weathering zone-bedrock” with different clay layers and bedrock thicknesses.Therefore,the failure characteristics of overburden rock (soil) and height of development were obtained,the sand inrush disaster factors and prediction criterion were analyzed,and the technical means of prevention and control of water inrush of sand were accordingly proposed.The results show that the overlying rock (soil) damage development height and characteristics were varied because of the control effects of different bedrocks and soil thicknesses under the condition of “sandy-soil-rock type of overlying strata” in the shallow buried coal seam.Water and sand,channel,power source,and space were the main factors causing the disaster of water inrush of sand in unconsolidated aquifer.The prediction criterion of sand inrush has been proposed.The sand inrush disaster of shallow coal seam was controlled through preventing roof cut,pumping aquifer head pressure,locally grouting and fixing sand and reasonably retaining the coal rock pillar.