Study On Roof Broken Characteristic Of Gateway Cutting Through Fault

Fault destroys the continuity and integrity of rock stratum which leads to the cracked rock with low and complicated stress character. And this induces the flaking easily. There are often two projects when the gateway cuts through the fanlt. The first project is to reach the hanging coal seam before or during cutting through the fault with along a certain obliquity. The second is to dig up to the hanging coal seam after crossing the fault directly. The gateway under the two projects has been taken as research object in this paper. The advance peak stress distributing and the broken characteristic of the roof is analysed by the similarity analogue test. The breakage phenomena indicates that there are the maximal stress destruction point in the hanging wall and the footwall when passing though the fault.The destruction of gateway roof is a result which affects together by three stresses loads. The first stress load is caused by the redistribution of the horizontal stress after the gateway is excavated.The second sress load is caused by the redistribution of the two laterals stress assemble region.after the vertical stress redistributed.The third is the detached stress of the vertical fault face which is formed by extrusion of the hanging wall.On the base of the theoretical analysis,it made a theoretical formula about the maximal stress destroys point and a theoretical formula about the roof convergence which using to cut through the fault.The distributions of advance stress displacement and Plastic zone in the surrounding rock about gateway cutting through fault under two different ways have been analyzed by using of a three-dimensional finite-difference FLAC3D program. And the resuts of two ways have been compared with each other. So the law of the similarity analogue test have been approved by it.At last a project have been put up on the base of the theoretical formula and the productive practice in chensilou mine. The field observation of the way has been done. The results are satisfied.It can be used as a reference to other gateways in the similar conditions.