采空区上覆岩层“三带”划分数值模拟

Numerical simulation for the “three zones ”division in the overlaying rocks of the goaf

采空区＂竖三带＂的确定,是合理设计高抽巷布置层位和确定高位钻孔终孔位置的前提。依据王庄矿提供的地质资料,结合实验室测得的煤层顶底板岩石力学参数,采用岩石质量评分法,计算得到各岩层合理的节理间距及岩体力学参数,并将其应用于CDEM软件中,对王庄矿8101工作面采动岩层进行数值模拟,分析了煤层开采过程中上覆岩层破断与冒落规律,并得出采空区＂竖三带＂的分布范围：采空区冒落带范围为0~25 m,裂隙带范围为25~65 m。将数值模拟结果与经验公式的计算结果、现场高位钻孔考察结果进行比较,结果表明：3种方法得到的冒落带范围基本一致,为0~25 m;经验公式计算得到的裂隙带高度较另外两种方法得到的结果小;数值模拟得到的＂竖三带＂高度更符合实际情况。同时也验证了CDEM软件在采空区上覆岩层运动的适用性。

Based on the geological data provided by the Wang Zhuang coal mine in combination with the testing results of the mechanical parameter of the rocks in the coal seam and the strata measured in the laboratory conditions, this paper has worked out the rational spacing and the mechanical parameters of the joints with the rock-mass rating method and applied the rock mechanical parameters via the CDEM （ Continuum-based discrete element method） software. And, then, this paper has made a simulation of the movement of overburdened strata under mining in 8101 working face of Wang Zhuang mine. We have also analyzed the breaking and caving regularity of the overbur- den with the gradual progression of the working face, when the over- lying strata began to rupture, break-down and get bending under the action of the gravity stress of the strata, with the falling rock irregular stacking in the mining area, and the caving zone, the fractured zone and curve subsidence zone formulated in the goaf. The determination of ＂vertical three zones＂ in the goal is the premise for the reasonable design and arrangement of the high-level borehole bottom location, which is also important to ascertain the layout position of the high lev- el suction roadway. Thus, it can concluded that the distribution range of goal ＂vertical three zones＂ in the caving zone is about 0 - 25 m while the range of the fractured zone is about 25 - 65 m. Then, we have compared the simulation results with calculation results by using an empirical formula and investigation results by the high level bore- hole. The comparison result of our investigation can be stated in the following way ： the results of the caving zone by the three methods are about 25 m, which is basically in agreement with the actual situation, but the height of the fractured zone calculated in the empirical formula is 40.5 - 51.7 m, which is less than the results by the other two methods, the numerical simulation is more tally with the investigation of the actual situation. As the same time, our study also verifies the applicability of CDEM in the pursuit of the overlying strata move- ment.