Analysis of Roof Structure on Longwall Remaining Coal Pillars Support Mining and Its Application

In longwall remaining coal pillars support mining,if the coal pillars are very small in size,the roof cutting accident is likely to happen in a limited exploitation area;while if the coal pillars are very large in size,roof falling crossing the mining area is likely to happen.According to building mechanics model in order to solve these two kinds of roof falling,the continuous beam model is established to calculate the stressed state of coal pillars with different properties.Then the software RFPA2D is used to numerically simulate the failure of surrounding rocks in mining area of Guojiawan coal mine.Meanwhile,the roof structure is analyzed,obtaining two different roof falling characteristics corresponding to the two problems.On the basis of this,we have proposed a scheme in which the coal pillars at some key points and in key area are monitored to solve the problem of two kinds of roof falling.