采场覆岩变形与破坏的分布式光纤监测与分析

提出了采用BOTDR分布式光纤传感技术,对煤层采动过程中覆岩变形与破坏的发育规律进行了监测和分析。以淮南矿区某工作面为例,介绍了监测孔的布置方式和传感光缆的安装方法,提出了采用钻孔安装技术将传感光缆植入到煤层顶板覆岩中,根据工作面回采进度,定期采集传感光缆的应变分布,分析了光缆的应变分布特征及其变化规律,得到了应变分布与地层的对应关系,发现应变分布是不均匀的,传感光缆的应变变化与覆岩模量呈反比,揭示了覆岩变形与破坏的发育规律。根据光缆的应变分布特征、传感光缆光损耗较大的点或者断点所处的层位,结合13-1煤覆岩的岩性组合,得到了垮落带和导水裂缝带的发育高度分别为12.5 m和40.0 m。

Monitoring and analysis of overburden deformation and failure using distributed fiber optic sensing

BOTDR, a kind of distributed fiber optic sensing technology, is employed to monitor the overburden deformation and failure during the coal mining. As an example in Huainan mining area, the layout and the installation technique of the sensing cables for overburden monitoring are designed. The sensing cables are implanted into the overburden by drilling installation technique. The strain distribution of the sensing cables is collected regularly according to the mining schedule. The characteristics and variation of the strain distribution are studied to reveal the relationship between the strain distribution and strata. The strain distribution is not uniform, which is relatively larger in the soft strata, such as mudstone, than that in the hard strata, such as sandstone. The deformation and failure of the overburden are also obtained. Based on the strain distribution and the breakpoint position of the cables, the heights of the caving zone and fractured zone are 12.5 m and 40.0 m respectively with the consideration of the overburden lithology and stratum combination above 13-1 coal seam.