Research on mining damage characteristics of roadway support structure in high stress area
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摘要: 高应力区巷道围岩裂隙发育,支护结构更易受采动影响而失稳破坏,而目前对巷道支护结构在采动过程中破坏演化特征的研究鲜有报道。针对双柳煤矿3316工作面地质特征,采用井下动态载荷实测、原位探测、数值模拟等方法,对3316抽采巷支护结构受采动影响破坏动态演化特征进行研究。结果表明:① 采动对高应力区巷道支护结构动态载荷影响明显,采动影响增强系数达2.1~5.8,致使部分锚杆(索)达到屈服极限甚至发生破断,巷道围岩有失稳破坏风险。② 采动应力增大引起围岩内部次生裂隙扩展,集中在0~2.44 m范围内,围岩裂隙受采动影响系数为1.92~2.54,围岩黏聚力减小,加速支护结构破坏,导致巷道变形加剧。③ 采动对支护结构破坏影响具有显著的时效特性,工作面超过测点10~70 m处支护结构受力受采动影响最明显,且两帮支护结构受力具有非对称性。通过优化锚杆强度、锚索直径及间排距等关键支护参数,可有效提高支护强度,巷道顶板变形量为146 mm,较优化前减少了71.7%,实现了巷道围岩稳定控制。Abstract: There are fissures in the surrounding rock of the roadway in the high stress area, and the support structure is more likely to develop instability and damage due to mining. At present, there are few researches on the damage evolution characteristics of the roadway support structure during mining. In the context of the geological characteristics of the 3316 working face in Shuangliu Coal Mine, the dynamic evolution characteristics of the support structure of the 3316 extraction roadway under the influence of mining are studied using the methods of mine dynamic load measurement, in-situ detection and numerical simulation. The results show that: ① Mining has significant influence on the dynamic load of the roadway support structure in the high stress area, and the mining influence enhancement factor reaches 2.1-5.8, resulting in some anchors (cables) reaching the yield limit or even breaking. Therefore, there are risks of instability and damage of the roadway surrounding rock. ②The increase of mining stress causes the expansion of secondary fissures inside the surrounding rock, which are concentrated in the range of 0-2.44 m. The coefficient of fissure expansion of the surrounding rock affected by mining is 1.92-2.54. The cohesion of the surrounding rock is reduced, which accelerates the damage of support structure and leads to the increase of roadway deformation. ③The influence of mining on the damage of the support structure has significant time-dependent characteristics. The force of the support structure at the working face over 10-70 m from the measurement point is most influenced by mining, and the force of the two sides of the support structure is asymmetric. By optimizing the key support parameters such as anchor strength, anchor cable diameter and inter-row spacing, the support strength can be effectively improved. The deformation value of the roadway roof is 146 mm, which is 71.7% less than the deformation before optimization, and the stability control of the roadway surrounding rock is obtained.
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