房式采空区失稳煤柱下回采异常矿压发生机理

Occurrence Mechanism of Abnormal Pressure with Mining under Instability Pillar of Room and Pillar Goaf

针对神东矿区石圪台煤矿31201工作面在上覆房式采空区失稳煤柱下回采期间矿压显现异常问题,利用现场实测和理论分析方法,对失稳煤柱下回采矿压显现异常的机理进行了研究。结果表明:失稳煤柱下回采期间,上煤层失稳煤柱冒落覆岩断裂岩块间不能形成铰接结构,且工作面上方冒落覆岩上覆岩层断裂岩块与其前方岩层共同向下运动,从而增加了下煤层顶板受力,使工作面呈现来压步距减小、来压强度增大的特征;由于失稳煤柱覆岩对煤层间岩层的作用力相比出集中煤柱期间小,因此未发生动载矿压灾害;煤层间岩层厚度的增加将减小下煤层顶板受力,进而减小失稳煤柱下回采矿压显现强度;提出在上煤层房式采空区失稳煤柱覆岩运动较充分后再进行下煤层开采的控制措施。

In order to solve the abnormal pressure problem of 31201 working face during mining period under up instability pillar of room and pillar goaf of Shigetai coal mine in Shendong mine district, on the basis of field measurement and theory analysis, the mech anismof abnormal pressure was studied. The results showed that the broken rock block that formed by upper instability pillar overburden fall could not formed hinge structure, and the overburden broken rock block that formed by falling overburden ahead working face and its front rock strata moved downward together, and roof pressure of lower coal seam would increased, the characters of working face that pressure interval decreased and pressure strength increased appeared, the interaction that instability pillar overburden to rock strata of inter coal seams was smaller than the value during concentrated pillar period, so dynamic pressure disaster was prohibited, roof pressure of lower coal seams would be decreased with the thickness of rock strata increased inter coal seams, then mining pressure strength would be decreased under instability pillar, and some controlling measures, such as lower coal seam mining should be started after overburden of up coal seam room and pillar goaf instability pillar movement fully.