浅埋近距煤层群开采扰动载荷传递作用分析

Analysis of mining disturbance loading transmission in shallow close coal seams group

针对陕北浅埋近距煤层下层煤层开采顶板来压剧烈的问题,采用物理相似模拟实验以及理论分析的方法,对浅埋近距煤层薄顶板载荷传递作用进行了分析,深入研究了浅埋煤层长壁开采的矿压显现规律、顶板破坏机理与载荷传递之间的规律.研究结果表明,浅埋近距煤层矿压显现的基本特点是载荷传递作用明显,来压强度剧烈,超前应力峰值主要集中在工作面前方20 m左右,超前支承压力显著影响距离为40 m左右,一般在6~10 MPa,应力集中系数范围在2~3.3.薄顶板破断首先在煤壁前方老顶上部产生拉裂隙,薄顶板所受荷载较大且破坏严重,顶板周期性破断形成微弧层状岩板,层状岩板回转可形成铰接结构,出现"二次成拱"现象.经过计算得出载荷传递因子为4.66.通过声发射监测得出,信号以高频率高能量信号为主,声发射信号由小突然增大,或是在连续增加时突然减小,表明岩层发生明显荷载传递作用.

The study on loading transmission of thin coal roof in shallow contiguous coal seams was applied by physical simulation experiments in order to solve the problem of severe roof weighting . Trai ts of underground pressure and relationships between roof fracture and loading transmission were clear. It indicated that strata behaviors in the study area were salient definitely and pressure intensity was violent in general. The distance between working face and stress peak zone is about 20 m while the distance of abutment pressure significantly affect is about 40m. The value of stress is generally 6 - 10 MPa and the range of stress concentration factor is 2 to 3. 3. The same vein main roof was apt to cause tension cracks in the front of the working face. Periodic pressure resulted in bedded rock plates being differential arc which would rotate to form hinge structure ebringing abour the phenomena of re -arch. The load-transmitting factor is 4. 63 by calculating. According to acoustics emission （AE） monitoring,high frequency and energy signals were dominant. Fur thermore,strata caused obvious loading transmission when AE signals increased abruptly or decreased after continuously raising.