浅埋煤层开采覆岩运动规律模拟与试验研究

Simulated and experimental study on the displacement tendency of the overlying strata in the mining of the shallow-buried coal seam

为了进一步掌握浅埋煤层开采覆岩运动规律,以神东矿区某矿22616面为工程背景,采用数值计算与相似试验相结合的方法研究了浅埋煤层开采覆岩下沉位移与应力分布特征,并进行了现场验证。发现现场监测数据和数值计算与相似试验结果较为一致,表明22616面属于典型浅埋煤层工作面,老顶初次来压步距46~48 m,周来压步距12~19 m,来压期间老顶瞬间垮落,下沉位移明显,台阶下沉特征显著;随工作面推移,采场前方煤体20 m范围内出现超前支承压力,应力峰值达到4.3 MPa,因此应提前采取加强支护措施。

In order to further disclose the displacement regularity of the overlying strata in the process of shallow buried coal seam mining,the present paper attempts to characterize the subsidence displacement and stress distribution of the overlying strata through a numerical calculation and simulated experiment based on the engineering background of No. 22616 working face in a mine of Shendong coalfield. The results of the numerical calculation and the simulated experiment have been verified through the field observation and examination,thus,implying that the first weighing distance of the main roof turns to be 46 m while the simulated experiment results reveal the distance is equal to 48 m. On the other hand,the periodic evaluation distance gained from the numerical calculation varies from 12 m to 17 m whereas the data gained from the simulated experiment ranges from 14 m to 19 m.In addition,the numerical calculation results prove that the greatest subsidence displacement and the vertical stress of the main roof should be 3. 5 m and 3. 5 MPa,respectively. And,in contrast,the same data gained from the simulated experiment turn to be 3. 7 m and 4. 3 MPa. Moreover,the results of the spot observation imply that the first measured distance of the main roof should be 45 m with the average working resistance of each support being 9 808 k N. Furthermore,the field observations also demonstrate that the periodic weighing distance of the main roof is approximately 10 m whereas the average working assistance strength of each support is 8 453 k N. Therefore,the both results of the numerical calculation and the simulated experiment tend all to be closely equal to or consistent with the regularities of the data monitored on the spot. And,consequently,the main roof instantaneous caving is likely to reduce the obvious sidestepped subsidence in weighing the stope which may lead to great subsidence displacement of the overlying strata. At the same time,the abutment bearing stress may turn up in the coal seam about 20 m ahead of the stope while the gradual advance of the working face and the peak stress are prone to reach 3. 5-4. 3 MPa,which would make it necessary to strengthen the support ahead of the schedule. Thus,the research results of the overlying strata movement regularity should be taken as a useful proof to provide a significant reference to the control of the movement of overlying strata during the shallow buried coal seam mining.