葛泉矿坚硬顶板综放开采三维数值模拟

3D Numerical Simulation of Top Coal Caving with Hard Roof in Gequan Mine

为了揭示以大青灰岩为坚硬基本顶的综放工作面开采过程中顶板应力分布及其演化特征,根据邢台葛泉矿风井1192综放工作面工程地质和开采技术条件,结合顶板坚硬、初次来压冲击大、动载系数高等特点,运用数值模拟(FLAC3D)程序对不同直接顶厚度条件下的综放工作面开采过程进行了三维计算和综合分析.研究表明,在10 m范围以内,直接顶厚度越大,基本顶的初次来压步距就越大,并在10 m处达到峰值,容易造成冲击地压;俯采工作面的围岩变形破坏力学过程和应力转移模式,是造成顶板来压前后最大主应力位置差异性的重要原因.研究成果为确定基本顶与工作面之间的安全距离、预防冲击地压、保障工作面安全生产提供了重要的理论依据.

The stress distribution and its evolution of hard roofs （Daqing limestone） different in thickness during fully mechanized top coal caving were numerically simulated. The simulation was carried out by using program FLAC^3D based on geological condition as well as mining technical condition in combination with the characteristics of hard roof, great impact of first weighting, and big dynamic load coefficient. The results show that first weighting interval of main roof increases with the increase of direct roof thickness and reach the peak value within 10 m, quite easy to induce rock-burst. In addition, the position difference of the maximum principal stress is mainly affected by mechanical failure process of surrounding rocks and transfer mode of stress. All these results have provided a theoretical basis for determining the safety distance between hard roof and working face and preventing rock-burst from taking place.