分岔合并下伏煤层破碎顶板超前注浆加固技术

Pre-grouting Technology for Broken Roof of Lower Coal Seam of Splitting and Merging Coal

分岔合并下伏煤层分层开采中,上覆煤层的采动对底板有一定的破坏影响范围,导致下层煤工作面顶板破碎,严重影响下伏煤层的正常回采。针对淮北矿业(集团)有限责任公司许疃矿71煤与72煤分岔合并现象,通过理论分析和数值模拟分析了7118工作面采动影响下底板破坏深度的范围;通过室内力学试验确定了最佳浆液水灰比为1∶1,水泥-水玻璃体积比为1∶0.4～1∶0.6之间;设计了7225工作面顶板注浆参数和注浆孔布置;通过数值模拟、相似模拟综合分析了预注浆加固效果,注浆后煤壁及顶板稳定性明显增强,顶板控制效果明显。

In the layering mining of lower coal seam of spilling and merging coal＇, the overlying coal mining has a certain destructive effect on the floor, resulting in cracking of the roof of lower coal seam and it seriously influenees the normal mining of the lower coal seam. Considering the condition of splitting and merging of 71 and 72 coal seams in Xutuan Mine, Huaibei mining （group） Co. , Ltd. , the scope of destroying depth of the floor under the effect of 71 18 working face mining is analyzed by means of theoretical analysis and numerical simulation method. By mechanical tests it is determined that the best water-cement ratio of paste is 1 ： 1, the volumetric cement-silicate ratio is be- tween 1：0.4 to 1：0.6, then the grouting parameters and grouting hole layout for 7225 working face roof have been de- signed. The pre-grouting effect is analyzed through numerical and analog simulation. The industrial experiment shows that the rib and roof stability is significantly enhanced after grouting, and the roof control effect is obvious.