摘要
本文以缓斜特厚煤层为研究对象,用相似模拟实验和数值模拟两种方法对放顶煤采场老顶运动失稳做了综合研究,首次提出了放顶煤采场上覆岩层的大结构形式为“搭桥结构”,并对该结构的初次失稳、周期失稳及由此施加于放煤支架上的载荷进行了较为详细的研究。这对放顶煤开采实践理论研究具有一定的指导意义。
By means of both similitude test andnumerical simulation, the papercomprehensively studied the destabilizationof the main roof of the stope mined withtop coal caving in gently inclined extrathick seams. It suggests that the generalstructure of the overlying strata is a 'bridg-ing structure'. The paper, on this basis,rather exhaustively investigated the first destabilizing, periodical destabilizing of thestructure and load resulted therefrom onsupports. The paper considers that beforethe collapse of the roof strata, at any pointin the strata the horizontal displacement, u,and vertical displacement, v, areexponential functions of the distance fromthe initial point, x: u=a·e^(b·x) and v=c·e^(dx) The subsidence for mining with topcoal caving is much larger than that forslice mining. The deformation in roof stra-ta may be divided into three zones: zone 1,the original zone, over 100 m ahead of theface with little deformation, may be con-sidered as non-deformed zone; zone 2, thecompressive zone, up to 10 m ahead of theface, where the vertical deformation islarger than the horizontal; and zone 3, thetensile zone, from face to caving line, wherefissures well developed with remarkablevertical and horizontal displacements.When the top coal and roof strata de-formed and subsided in advance, the frontabutment point of the main roof rockbeam breaks in the coal wall. The structuremay be 'rare bridging', as the main rooffractures and destabilizes. Thedestabilization of 'bridged structure' haslittle influence on the stope. Theoretical analysis indicates that thefirst breaking and destabilizing space of themain roof rock beam increases with theback up of the top coal and immediateroof. After the breaking of the rock beam,its front half part is liable to turn into bal-ance, but the rare half destabilizes andforms a 'rare bridging structure'. The firstweighting space, L, is not equal to thespan, Lo, of the first breaking anddestabilization, but L=Lo-l. The structureof main roof after the first destabilizing isan invert cantilever and becomes a 'frontbridging structure' following the periodicaldestabilization. The procedure of bridgingand the characteristics determines that theweighting intensity at the face mined withtop coal caving in gently inclined seam isrelatively low and the load exerting onsupports is light.
出处
《矿山压力与顶板管理》
1993年第3期76-82,240-241,共7页
Ground Pressure and Strata Control
