煤矿采空区矸石稳定性分析

Stability Analysis of Waste Rock in Coal Mine Gob

通过离散元软件PFC,建立了采空区矸石压缩模型,通过分析不同级配方案矸石压缩的力学特征,得出：岩层运动有很强的时间效应,矸石由垮落初期到压实末期,自身的松散系数可以递减15%～24%,开采垮落矸石大颗粒块体所占百分比越大,矸石松散体的碎胀系数变化越大,顶板运动稳定所需时间越长;伴随矸石松散体的不断压实,侧压系数不断增加,侧向膨胀压力最大可达垂直荷载的65%～83%,这一膨胀压力严重威胁着采空区两侧的巷道,大粒径矸石所占百分比越大,对侧压系数的影响越大;矸石散体在压缩过程中自身会发生转动,转动角度因矸石块度的不同而异,但总的来说转动范围集中于0°～360°,小粒径的矸石旋转角度较大。

By means of the discrete element software PFC,the waste rock compression model of coal mining area is established.Through analyzing the mechanical characteristics of different gradation schemes,we obtained that strata movement has a strong time effect and the loose coefficient of gangue can be reduced 15% to 24% from the earlier caving time to the compaction stability stage,and the particles block percentage of mining caving gangue is high,gangue lycopodium dispersion broken expansion coefficient changes more,required time of roof movement stability is longer.With continuous compaction of gangue lycopodium dispersion,lateral pressure coefficient increases,lateral expansion vertical load of pressure is up to a maximum of 65% to 83%,the swelling pressure is a serious threat to the mining empty area on both sides of the roadway,the greater of large size gangue percentage,the bigger influence on lateral pressure coefficient.Gangue dispersion in the compression process itself will rotate,rotating angle varied with different degrees of waste rock,but overall rotation range is from 0 to 360 degrees,and the small size of the waste rock rotation angle is larger.