逆冲断层下冲击危险煤层采场矿压规律试验研究

Experiment study on strata behaivors law of mining face with outburst risk coal seam under thrust fault

为了了解义马矿区F16大型逆冲断层对该矿区5个生产矿井回采工作面的矿压的影响情况,在考虑断层结构面的分形特征和断层两侧覆岩赋存特征的基础上,通过搭建大型相似模拟试验平台,采用位移、应力等多种监测手段,研究了随工作面向断层方推进过程,靠近断层附近时工作面覆岩运动特征和矿压显现特征。研究结果表明,受断层构造运动和上覆巨厚砾岩的影响,当工作面未进入断层影响范围前,工作面覆岩"三带"特征明显,底板基本不受采动应力影响。进入断层影响区后,顶板离层量呈跳跃式增长,采动应力诱发断层"活化",底板应力达到最大值。当推过断层一段距离后,随着上盘关键岩层悬臂岩梁长度的增加,工作面煤壁发生屈曲破坏,底板应力增加,待岩梁垮断挤压应力释放后,底板应力随之下降,伴随着工作面上方"短砌体梁"结构发生切落且沿断层面滑动。

In order to figure out the effect of F16 large thrust fault to five produotion mines in Yima Mining Area, a large similar model was built.During the model building, the fractal features of fault plane and occurrence characteristics of overburden on both sides of fault were considered.According to the monitoring results of displacement and stress, the characteristics of overburden movement and strata behavior law was studied with mining face advance to the fauh.It was found that the overburden＂ three-zone＂ was obvious and the floor was unaffected before the mining face entered to the influence scope of fault.After the mining face was in zone,the roof abscission layer amount had a leap-growth and the stress in floor reached maximum,the fault was activated.When the working face crossed the fault a certain distance, with the length of cantilever rock beam increasing, the working face coal wall was yield failure and the floor stress increased.After the cantilever rock beam broken and its bearing stress released,the floor stress decreased.Meanwhile,the＂ Short Voussoir Beam＂ structure which above mining face cut down and slide along the bedding.