煤系地层覆盖下铝土矿开采岩体地压活动规律研究

Experimental study on ground pressure activity law of bauxite mining rock covered by coal measures strata

通过统计山西某煤系地层覆盖下铝土矿采区内的勘探钻孔资料,铝土矿采矿厚度和煤铝之间岩层厚度的采厚比分为6.9、11.9、17.4三种情况。根据采厚比的不同情况,建立煤下铝矿体回采模型,研究分析煤下铝房柱法开采过程中应用崩落协同充填技术处理采空区时覆岩地压活动规律。铝土矿的开采使上覆岩层垂直应力释放,水平应力略有增加;煤下铝回采过程中,同步崩落顶板处理采空区,对上覆岩层沉降、上覆煤层应力释放具有显著的控制作用,均未出现铝土矿的开采导致煤层拉剪破坏的情况,同时未超过规范对于地表保护等级Ⅰ级的水平变形和倾斜的允许值。根据数值分析结果建立了煤层底板水平变形、倾斜随采场沿倾向推进之间的线性关系,沿倾向总的开采阶段数不宜超过11个。

The data of exploration boreholes in a bauxite mining area covered by coal measure strata in Shanxi were analyzed.Thespecific values of mining thicknesses of bauxite and coal-aluminum strata were divided into 6.9,11.9 and 17.4.On this basis,a mining model of the underlying aluminum ore body was established,and the research and analysis on the law of overburden ground pressure in the process of under-coalbauxite mining with room and pillar method and applying caving and filling technology to treat goaf were conducted.The mining of bauxite can release the vertical stress in the overburden,and horizontal stress increased slightly.In the process of aluminum mining under coal,synchronous caving roof deal with the goaf can control the settlement of overlying strata and stress release of overlying coal seam,without resulting the mining of bauxite being in the failure of seam tension shear and exceeding.A specification for the surface protection levelⅠ horizontal deformation and radial tilt.Based on the results of numerical analysis,the linear relationship between the horizontal deformation and inclination of coal seam floor and the inclined advance of stope were established,and found that the total number of mining stages along the trend should not exceed 11.