上行开采顶板煤巷围岩稳定性控制技术研究

针对淮南矿区煤层群上行卸压开采被保护层回采巷道围岩控制的技术难题,采用数值模拟和物理模拟方法研究了下部煤层卸压开采后项板巷道应力场和裂隙场时空演化规律,以及卸压开采动压影响条件下,复合顶厚度小于锚杆锚固范围、复合顶厚度与锚杆锚固范围相当、复合顶厚度大于锚杆锚固范围时巷道变形破坏规律,结果表明:下伏采动和巷道掘进形成的叠加应力决定巷道围岩应力分布和裂隙演化特征,锚杆支护能够优化围岩的应力场和裂隙场,保证围岩整体结构稳定;复合顶厚度大于锚杆锚固范围的巷道安全状况最差,巷道变形破坏最严重.在此基础上提出了保障顶板安全、加固两帮、强化关键区域、增大锚固范围的控制原则,给出了以新型“三高”锚杆为基础的立体式锚索梁承载结构组合支护技术,并成功应用于工程实践,取得了良好的支护效果.

Study on Surrounding Rock Control for Mining Roadway of the Overlying Protected Seam in Ascending De-Stressed Mining

Surrounding rock control in the overlying protected coal seam is a challenging topic of de-stressed mining of multi-seams.Based on current research on roadway control,a numerical simu-lation model was established to study stress field and fissure field before and after roadway excavation during underlying mining.Meantime,a physical simulation mode with the complex textured-roof and varying thickness was used to study roadway instability and collapse caused by dynamic pressure as well.The results show that when thickness of the roof is bigger than that of the bolted depth.The roadway situation is in the worst and the roof has the greatest possibility to lose its stability.Then a se-ries of control principles have been proposed,such as strengthening roof,reinforcing both sides,strengthening the key area and strengthening bolted area.Therefore,combined supporting technique of tridimensional cable bolt beam structure based on new "three-high" bolt has been put them into practice finally,which showed that a better supporting effect was obtained.