固体充填采煤超大跨度开切眼成巷及支架安装技术

为解决固体充填采煤超大跨度开切眼围岩稳定控制难题，基于充填采煤液压支架的结构特点，提出支架整体安装一次成巷法、后顶梁滞后安装一次成巷法和降低后顶梁安装二次扩面法3种不同的开切眼成巷方法。通过综合分析支架安装工艺、大断面顶板悬露时间及围岩控制等因素，得出了降低后顶梁安装二次扩面法更有利于围岩稳定的结论。以河南某矿10.2 m长充填采煤液压支架为例，采用降低后顶梁安装二次扩面法的开切眼成巷工艺，设计了总跨度8.7 m、长度100 m的开切眼，采取高预紧力锚杆锚索和二次扩面段单体液压支柱加强支护的围岩控制方案，利用数值模拟对开切眼围岩变形量和塑性区破坏深度进行分析，确定初次导硐跨度及二次扩面长度分别为5 m和12 m。工业试验及现场实测表明，对于固体充填采煤超大跨度开切眼采用降低后顶梁安装二次扩面法，可以有效的控制超大跨度开切眼变形，确保充填采煤工作面的快速安装，达到了预期的效果。

Tunneling method and support installation in large span open-off cut of solid backfill mining

In order to solve the stability control problems of surrounding rocks of a large span open-off cut in solid backfill mining，three different open-off cut forming methods including support integral installation under once tunneling，posterior top beam following installation under once tunneling and lowering posterior top beam installation under twice tunneling were proposed based on the structural features of a solid backfill hydraulic support.From the comprehensive analysis of indicators such as support installing technology and the exposure time of large section roof，the lowering posterior top beam installation under twice tunneling method was proved to be better for surrounding rock stability.Taking a 10.2 m length solid backfill hydraulic support of a mine in Henan as an example，a 8.7 m width and 100 m length open-off cut was designed using the lowering posterior top beam installation under twice tunneling.High pre-stressed bolts and cables in the whole tunnel and hydraulic props for strengthening support in the twice tunneling segment were adopted as the scheme for stability control of surrounding rocks.The reasonable width of primary tunneling and length of twice tunneling are 5 m and 12 m respectively from the numerical analysis results of the open-off cut deformation and failure depth of plastic zone.The proposed tunneling method and support installation are successfully applied to the coal mine in Henan，the in-situ tests show that the deformation of large span open-off cut is effectively controlled and the installation of open-off cut was smooth.