充填开采覆岩裂隙时空演化实验研究

以任家庄煤矿拟充填工作面为工程背景，通过相似材料模拟实验，统计分析了覆岩裂隙数量、角度、长度、宽度等参数，研究了充填开采覆岩裂隙的时空演化规律和分布特征。结果表明，煤层开挖充填距离较短时，近煤层的低位岩层首先产生横向裂隙，裂隙数量少、角度呈近水平。随着开挖充填距离的增加，横向裂隙的数量和长度均呈增加趋势。横向裂隙衍生出的非贯通性纵向裂隙基本分布在煤柱与采空区交界的区域内，其长度相对较短，角度普遍大于180°。覆岩裂隙由低位岩层逐渐向高位岩层发育扩展，裂隙分布范围逐渐扩大，在关键层处裂隙发育受到一定阻碍，采充区中部覆岩的裂隙发生缩小和闭合现象，减缓覆岩裂隙数量的增加|停采后的覆岩裂隙宽度普遍小于0.8mm，由裂隙两端向中部位置，裂隙宽度呈现先增大后减小的变化趋势|开采起始位置的覆岩裂隙宽度比停采位置附近的覆岩裂隙宽度要大。最后针对充填开采覆岩裂隙演化过程提出了有针对性的控制措施。研究结果对于深入认识导水裂隙发育演化和保水采煤具有重要意义。

Study on mechanical properties and engineering application of gob-side entry retaining Combined filling body

In order to study the optimal proportion of double filling wall along goaf retaining wall and its influence on roof gas leakage of working face, Taking the 2603 working face of Zhangcun Coal Mine as the engineering background, By preparing cubic composite samples with different proportions of concrete and high water material, the optimal proportions were selected from the study of mechanical properties and macroscopic fracture forms of the composite samples with different proportions,and based on the characteristics that the upper soft layer can fully connect the roof and prevent the upper gas leakage, the gas concentration of the roadway is monitored.The results show that when the proportion of high water material is 10%, 20%, 30%, 40% and 50%, the peak strength of the concrete decreases by 18.95%, 44.23%, 52.31%, 60.78% and 79.68%, respectively, compared with the peak strength of pure concrete. When the proportion of high water material is less than 20%, the combined specimen has the effect of letting pressure while ensuring a certain strength.When the proportion of high water material is more than 20%, the high proportion of soft stratified material will reduce the supporting effect of high strength material at the bottom, thus affecting the overall strength of the specimen. The application results show that the gas concentration can be effectively reduced and the effect of roadway retention is good.