为确保高应力大阶段二步采场高效安全回采,采用ANSYS对二步采场分段开挖过程进行稳定性分析,得到了各分段采场顶板和充填体的应力分布规律。结果表明,采场顶板处产生的最大拉应力(0.21～0.36MPa)大于矿体的抗拉强度值(0.17MPa);充填体距离采场顶板1m位置处有最大压力(0.90～2.00MPa),接近其抗压强度值(2.00MPa);随着开采分段向上推进,采场顶板的拉应力和充填体内的压应力均有降低趋势。针对数值模拟中二步采场存在的安全隐患,提出采用预护顶中深孔下向凿岩分段充填法回采二步矿房,预护顶采用预应力树脂锚杆+钢带(金属网)+喷浆联合支护方式,并根据数值模拟中获得的松动圈半径确定了支护参数。将支护方案应用到工程试验,试验采场安全效果较好。

In order to guarantee the safety and mining efficiency of the high-stage second-step stopes in the high-stress situation, finite element program ANSYS is used to analyze the stability of the stopes for section-by-section excavation. And the stress and strain distribution of roof and filling body is obtained from the simulation. The result shows that the maximum tensile stress (0.21-0.39MPa), located at the roofs, is more than tensile strength (0.17MPa) of ores. The maximum pressure (0.90-2.00MPa), located at the filling body which is one meter away from the roof, approximately reach to the limitation of its pressure strength (2.00MPa). Tensile stress at roof and pressure stress of filling body with mining upwards present a declining trend. According to the hidden danger of the second-step stopes presented by numerical simulation, it is put forward to adopt medium-length hole downward sublevel drill and fill stoping with pre-protecting roof. And the combined supporting method that combines pre-stressed resin bolt, steel ban (metal net) and gunite, is used to pre-protect the roof. Support parameters are adopted based on the radius of loosening zone, which is confirmed through the numerical simulations. Effective support measures is put forward and applied to engineering tests, and then its result confirms the high safety and mining efficiency of the stope.