三软煤层综放工作面覆岩垮落及裂隙导水特征分析

通过大南湖一矿三软煤层工程地质条件及煤岩物理力学参数的综合分析与测定,开展了对应条件下的物理相似模拟,分析了综放工作面围岩运移及覆岩破坏高度,探索了现场支架实测阻力与覆岩裂隙导水位置、导水量间的关系。综合分析表明:1303综放工作面顶板垮落带高度为20 m,模型表面裂隙延伸高度观测结果与3D钻孔电视合成的钻孔内壁破裂剖面揭示出的裂隙延伸高度均为98 m,与经验公式计算基本一致。工作面超前影响范围随开采范围而增大,最终趋于稳定。1303综放面工作面划分为两个较为明显的压力集中区,工作面裂隙导水量、导水位置与压力集中区中支架压力变化相关,覆岩裂隙导水显现的位置处在工作面中下部顶板压力集中显现区(2区)的位置几率较大。建议1303工作面提前疏放上覆含水层以及老窑积水的同时,加强对两个压力集中区(1区和2区)的监测,尤其是2区,密切关注架后顶板垮落情况与工作面淋水量变化,及时的给出来压预警与导水位置及导水量预测。

Analysis on characteristics of overlying rock caving and fissure conductive water in top-coal caving working face at three soft coal seam

With the specimens obtained from the Dananhu Coal Mine,according to the comprehensive analysis and determination of engineering geological conditions and the physical and mechanics parameters of coal-rock in three soft coal seam from Dananhu No.1 coal mine,a physical simulation model experiment has been built to analyze the moving law of surrounding-rock and the disturbed height of overburden stratum in the fully-mechanized top-coal caving working face.The relationship between the measured resistance of field support and the position and water volume of overlying rock fissure conductive water is explored.The results show that the roof caving zone height at 1303 working face is 20 m,both the heights of fissure conductive water obtained by the observation of surface crack extension height on the model and revealed by 3D borehole TV synthetic borehole profile are 98 m,which is consistent with the empirical formula.The advance-disturbance scope expands with the increase of mining area,and eventually tends to be stable.The 1303 working face is divided into two parts of the pressure concentration(No.1 area and No.2 area).The volume and position of fissure conductive water are related to support pressure change,the position of overlying rock fissure conductive water has bigger chance in the middle and lower part of working face(No.2 area).The authors suggest the overlying aquifer and gob water in the 1303 working face should be drained in advance,meanwhile,strengthen the detection of two pressure concentration areas,especially the No.2 area.The roof failure and volume changes of water-drawing should be paid more attention,giving the immediate strata behavior warning and prediction of fissure conductive water position and volume.