隧道下伏采空区稳定性及治理方案数值模拟

Numerical Simulation Analysis of Stability and Treatment Program of Goaf under Tunnel

隧道下伏采空区的潜在危害性评价及其处治技术研究日益受到重视。为治理平朔煤矿东露天矿运输专线隧道下伏采空区,利用FLAC3D对采空区稳定性及治理方案进行了数值模拟分析,得到了隧道下伏采空区在加固前后的受力和变形的特征规律;通过对仰拱厚度及采空区注浆料强度进行敏感性分析,得到了最优的加固措施。数值分析结果表明:在未加固的采空区上开挖隧道,采空区两帮岩土体受到较大的垂直载荷,隧道开挖底板出现了屈服剪切破坏,隧道拱腰及拱顶出现了屈服拉伸破坏,隧道底板最大沉降及不均匀沉降较大;在对采空区充填注浆及隧道底板浇筑仰拱的联合加固措施后,原采空区附近的应力集中区域得到很好释放,隧道底板最大沉降及不均匀沉降量大幅降低,岩土体的整体稳定性提高。

It is increasingly thought highly of hazardous assessment and treatment technology on the mined-up regions under the tunnels. In order to treat the goaf under tunnel for transport line of Eastern Open Pit, numerical simulation analysis on stability and treatment program of goaf were carried out with FLAC3D ,obtaining the rule of stress and deformation before and after the reinforcement of goaf under tunnel. The optimal reinforcement measure was got through the sensitivity analysis on the invert thickness and the strength of the grouting material. The numerical analysis indicated that： tunnel excavating above the unreinforced goaf made the sides of goaf suffer more vertical load. Shear failure occurred in the root of the tunnel and tensile failure occurred in the middle and roof of the tunnel. Meanwhile, there was a large settlement and unequal settlement in the root of the tunnel. After joint reinforcement of mined-out area grouting and tunnel floor pouring invert, the stress concentration near the mined-out area is well released, which significantly reduces maximum or uneven settlement in tunnel floor and improves overall stability of rock and soil.