南水北调中线工程郭村矿采空区段稳定性研究

Stability research on Guocun goaf area at Middle Route Project of South-to-North water diversion

南水北调中线工程禹州市郭村煤矿采空区地表形成了长1 700 m、宽400 m的移动盆地,采空区上覆岩体为典型的"三带型"(冒落带、断裂带和弯曲带)。通过布设高精度监测网,研究了施工前后采空区地表变形特征,监测结果表明,施工前,采空区地表移动已基本结束,处于稳定状态;施工期间,注浆造成应力重新分布,注浆区域内地表变形有明显振荡,而对注浆区域外的地表影响不大;施工结束后,地表变形均趋于稳定。采用FLAC3D有限差分软件,分别计算了渠道运行期间无渗漏、一般渗漏和严重渗漏3种工况下渠道和采空区变形和应力分布规律。计算结果表明,随着渗漏的严重,竖向位移和影响深度增大,但是增幅减小,最大值可达5.5 cm;影响宽度区域沿着渠道对称分布,均匀增大;水平位移逐步增大,且增幅增大,但最大值为7 mm,影响较小;采空区灌浆加固使应力重新分布,仅在采空区两端产生应力集中,渗漏工况下渠道过水荷载所产生的附加应力与自重应力相比很小,对采空区稳定性影响不显著。

For Guocun coal mine, Yuzhou city, the goaf surface has formed 1 700 m long and 400 m wide moving basin; the goaf overlying rock mass is a typical 'three zones'(in break, crack and bent zones) in South-to-North water diversion project. High precious monitoring networks are installed to research the goaf deformation characteristics during construction. The monitoring results indicate that the surface moving is over before construction. The surface moving in grouting area is obviously because of grouting; and the surface moving tends to stable after grouting. The deformation and stress of channel and goaf in three working conditions no-leakage, common-leakage and severe-leakage are simulated by FLAC3 D. The vertical displacement and effect depth increase with leakage become more serious but added value decreases; the maximum value is 5.5 cm; effect width is symmetrical along the channel and increases uniformly; horizontal displacement increases and added value increases, while the maximum value is only 7 mm.; grouting redistributes stress field and there is stress concentration at both ends of goaf area; during leakage working conditions there is no effect on goaf area from water and channel load.