深部连续开采充填工作面沿空掘巷围岩偏应力演化与控制

Evolution and control on deviatoric stress in surrounding rock of gob-side entry driving of filling face in deep continuous mining

为解决深部连续充填工作面沿空掘巷围岩控制问题,以邢东矿1128运输巷为工程背景,借助FLAC3D数值模拟软件,探究1126工作面采空区在不同充填率条件下沿空掘巷围岩偏应力分布规律,模拟分析充填开采工作面超前段受开采影响的围岩偏应力演化特征。研究发现:巷道浅部围岩形成环全断面低偏应力区,顶板低值区深度明显小于两帮与底板,低值区外的巷道四边均有一个偏应力高值区;围岩最大偏应力区位于巷道右上部,峰值大于20 MPa,当充填率大于90%时,巷道围岩四周偏应力值逐渐减小且沿巷道两帮呈对称分布;充填开采对超前段巷道围岩形成的高集中应力主要分布在工作面前方0~15 m,巷道顶、底板两尖角处围岩受巷道围岩偏应力影响形成4个“突出变形区”。结合模拟分析结果、锚杆索预应力承载结构及采空区高水材料充填性能,提出巷道围岩“超强锚杆+大直径高延伸率锚索”联合支护技术,并应用于现场工程实践,结果表明该技术可实现对深部连续开采充填工作面沿空掘巷围岩的有效控制。

In order to solve the problem of surrounding rock control of gob-side entry driving in deep continuous filling working face,taking 1128 headentry of Xingdong Coal Mine as the engineering background,the distribution law of deviatoric stress of surrounding rock of gob-side entry driving in 1126 working face under different filling rate was explored with the help of FLAC3D numerical simulation software,and simulated and analyzed the evolution characteristics of deviatoric stress of surrounding rock affected by mining.The results show that the shallow surrounding rock of the gob-side entry driving forms a low deviatoric stress area of the whole section of the ring roadway,the depth of the low value area of the roof is obviously less than that of the two sides and the floor,and there is a high value area of deviatoric stress on the four sides of the roadway outside the low value area;the maximum deviatoric stress zone of surrounding rock is located in the upper right of the roadway,and the peak value is greater than 20 MPa.When the filling rate is greater than 90%,the deviatoric stress value around the roadway surrounding rock gradually decreases and is symmetrically distributed along the two sides of the roadway;the high concentrated stress formed by filling mining on the surrounding rock of the roadway in the leading section is mainly distributed 0 m to 15 m in front of the working face.The surrounding rock at the two corners of the roof and floor of the roadway is affected by the deviatoric stress of the roadway surrounding rock to form four“prominent deformation areas”.Combined with the simulation analysis results,the prestressed bearing structure of rockbolt and anchor cable and the filling performance of high water material in goaf,the combined support technology of“super strong bolt+large diameter and high elongation cable”in roadway surrounding rock is proposed and applied to field engineering practice.The results show that this technology can effectively control the surrounding rock of gob-side entry driving of filling face in deep continuous mining.