坚硬顶板处理步距的数值模拟

Numerical Simulation of hard roof processing step

为了达到煤矿工作面安全、高产高效生产,改变坚硬顶板岩体的物理力学性质,以减小顶板悬露面积,防止或减弱这种大面积顶板来压相当重要。由于坚硬顶板跨落时矿压显现明显,一次跨落的面积大,高度大,有强烈的周期性来压,并有明显的动压冲击现象,所以在基本顶来压前必须对顶板进行处理。目前处理坚硬顶板的措施主要有两种:既注水弱化顶板和爆破弱化顶板。而处理步距的确定对于安全、高产高效生产起关键的作用,利用FLAC3D对某煤矿2#煤层进行数值模拟,表明当工作面推进距离达到28m时,超前支承压力峰值已经达到7.43MPa,集中系数约为1.55,此时基本顶对工作面产生的冲击作用已较为明显,所以对工作面进行强制放顶的步距不应该超过28m。

For safe production in the working face, it is important that changing the physical and mechanical properties of hard roof to reduce the roof hanging area, and to prevent or reduce large area roof pressure. Due to the hard roof pressure obvious as roof fall, the roof fall area and height is large, with strong periodical pressure and obvious dynamic pressure impact, so the roof must be handle before the pressure of the basic roof comes. At present, there are two main measures to deal with the hard roof： water-infusion weakening the roof and blasting weakening roof. And the processing step derivation playes a key role for safe, high productivity and high efficiency production. By FLAC3D numerical simulation of coal seam 2# ,the result shows that the rock peak pressure is 7.43MPa when the working face＇s advancing distance is 28m, and the concentration efficient is 1.55 ,and the basic roof impacts the working face obviously. So the processing step to the working face shouldn＇t exceed 28m.