高充填率开采地表下沉系数研究

Study on Surface Subsidence Coefficient of High Backfill Mining

为解决“三下”压煤问题,本文以邯矿集团亨健煤矿2515工作面为研究对象,对现场进行实测,计算地表实测下沉系数;采用文克儿地基假设方法,对比分析了不同开采方法采空区上覆岩层破断规律。结果表明:采用全部垮落法开采,推进距离等于直接顶的极限跨距(l=25.7 m)时极限挠度约为1.057 m,随着工作面推进,直接顶出现破碎;采用高充填率充填开采,充填距离等于25.7 m时,直接顶的极限挠度约为530 mm,出现“接顶”现象,等效采高远远小于直接顶和老顶的极限挠度,从而极大地抑制了直接顶、老顶的破碎和其他岩层的断裂和离层发育。现场实测与理论分析表明:高充填率充填开采条件下,以等效采高为采厚,地表下沉系数较全部垮落法增加15%左右。

In order to solve the problem of coal under three pressure to discover the law of surface subsidence with high backfill mining,the 2515 working face of Hengjian coal mine was taken as the research object in Handan Mining Group,the measured subsidence coefficient of the ground surface was calculated by the field measured conditions.The breaking law of the overlying strata with different mining methods in the goaf area were compared and analyzed by the Winker foundation assumption.The results shows that:by roof-caved mining,the limit deflection of the direct roof is about 1.057 m when the advancing distance is equal to the limit span(l=25.7 m),and the direct roof is broken with the continuous advancing of the working face;by backfill mining,the limit deflection of the direct roof is about 530 mm when the filling distance is equal to 25.7 m,and appeared"roof connection",the equivalent mining height is less than the limit deflection of the immediate roof and the main roof with high filling rate,which greatly restrains the fragmentation of the immediate roof and the main roof;Meanwhile,other rock fracture and delamination growth are suppressed.The field measurement results and theoretical analysis show that under the condition of backfill mining with high filling rate,taking equivalent mining height as mining thickness,the subsidence coefficient of the surface increases by about 15%compared with caving system.