重复采动下上覆高位巨厚岩层微震分布特征研究

Study on micro-seismic distribution characteristics of high-position and ultra thick hard overlying strata under repeated mining

以鲍店煤矿十采区3煤层开采为例,根据现场SOS微震监测数据,研究了上、下煤层重复采动下高位厚硬岩层的微震活动规律,分析了强微震分布与高位巨厚坚硬岩层的关系。研究表明:上煤层工作面的推进距离超过工作面长度后,高位硬厚岩层在工作面前方和采空区发生阶段性的高能量(104J)微震活动,并引起相邻采空区的连锁反应,微震活动强烈;下煤层重复采动时采出总厚度增加,高位硬厚岩层二次失稳运移,再发生阶段性强微震活动,但最大能量有所下降;微震大事件主要发生在高位巨厚岩层内,在时间上呈现阶段性,具有大步距式强微震与运移特征。

Taking No.3 Coal Seam of No. 10 Mining Distict in Baodian Mine as study object, and based on the SOS micro-seismic monitoring data,this paper studied the micro-seismic activities regularity of high-position ultra thick hard overlying strata when the upper and lower coal seams were repeatedly mined, and analyzed the relationship between the distribution of strong micro-seismic and the high-posi- tion ultra thick hard overlying strata.The study results showed that the high-position ultra thick hard overlying strata before working face and would cause the periodically high energy（ 104 J）micro-seismic activities and resulted in the chain reaction between the adjacent gob and strong micro-seismic activities when the advancing distance of upper working face exceeds the length of working face.When the lower coal seam was repeatedly mined, the total recovery thickness would increase,the secondary broken and migration of the high-position ultra thick hard overlying strata became larger further,the periodically strong micro-seismic activities would happen again,but the maximum energy would decrease.The large micro-seismic events mainly took place in the high and ultra thick strata and happened periodically in time sequence, and it also had characteristics of large drawing pace type of the strong micro-seismic and migration.