深部煤巷顶板冲击裂变失稳机制及其动力表现型式

冲击矿压85%发生在巷道中,随着开采深度的增加,冲击矿压发生的频次和灾害烈度都急剧增加,深部煤巷冲击矿压灾害防治已经成为一个亟待解决的技术难题。针对深部煤巷顶板冲击裂变失稳机制进行研究,基于弹塑性及断裂力学原理,分析了巷道顶板岩层集力聚能破断失稳机理,推导了巷道顶板冲击裂变失稳的承载、形变及能量条件,阐述了冲击动载作用下复合顶板"层间离层-岩梁开裂-动力震裂"的裂变失稳演化规律。深部煤巷顶板冲击失稳模式与顶板岩梁宏观主控裂隙的发育扩展关联密切,在高静载和强动压的叠加作用下,巷道顶板呈"一横五纵"6条主控裂隙展布发育,各横纵裂隙协同扩展直至汇合贯通,最终形成"门式"震裂块体瞬间推入巷道空间发生冲击破坏。最后揭示了深部煤巷顶板岩层动力破坏失稳的6种表现型式,提出了"顶部桁架锚索+跨中长锚索+顶角斜锚杆"强力联控支护对策。

Roof burst instability mechanism and dynamic characteristic of deep coal roadway subjected to rock burst

Rock burst occurring in deep coal roadway is a technical problem to be solved,85% of which occurs in the roadway,and its frequency and intensity increase dramatically with the increase of mining depth.This paper analysis the instability mechanism of deep coal roadway roof based on the elastic-plastic mechanics and fracture principle,expounds the rupture instability mechanism of roadway roof strata with increasing stress and energy,derives the load,deformation and energy conditions of rock burst,and elaborates the fission instability evolution law of composite roof which turns roof into the vicious circle of “interlayer separation-rock beam cracking-dynamic crack by dynamic load” or even instant caving.The instability process of deep coal roadway roof is closely related to the cooperatively extension of six main cracks under the superposition action of high stress and dynamic pressure.The six cracks of “one horizontal and five vertical” extend together and form a “door”-like breaking block to push into roadway and cause damage.The paper presents the six manifestation pattern of rock burst and dynamic instability,puts forward the effective unit control timbering countermeasure of “roof truss cable+roadway center long cable+roadway drift angle bolt”.