铁矿深埋巷道围岩变形与地应力关系研究

随着大量深埋地下工程的建设，尤其是大型矿山，与巷道围岩稳定有关的各种地质灾害问题突出，因此其一直备受关注。某铁矿巷道埋深450～800m，变形剧烈，局部持续大变形，呈条带状臌出。地应力实测结果表明，矿区地应力总体特征为σv≥σH〉σh，现今水平构造作用明显，最大水平主应力为13-21MPa，接近岩体自重。大变形洞段围岩为裂隙化岩体，强度低，蠕变性明显。有限元分析表明，巷道开挖后在边墙与顶拱和底板交界处产生约40MPa的高应力，造成了围岩变形破坏。后期围岩在高应力作用下产生大变形，其宏观变形破坏特征与软岩相似。另围岩加固与支护发现，普通的挂网喷锚支护已很难适应高应力条件下的岩体大变形。论文基于地应力实测结果，通过对巷道围岩大变形成因机制的探讨以及原加固支护效果的总结，为后期巷道围岩变形破坏的防治提供了参考。

Relationship between deformation of surrounding rock and in-situ stress in deep-buried tunnel

With the burial depth from 450m to 800m, the surrounding rock of a iron mine is deformed severely, supports lose their effects and the deformation is lasting. The testing results of in-situ stress shows that these tunnels are under the action of modem ground tectonic stresses with the maximum principal stress of 13 - 21MPa, and that the general feature of modem ground stress field is that σv ≥σH〉σh.The . The surrounding rock of strong deformation belongs to the fissured rock, whose strength is low. The results of FEM analysis show that the maximum stress within surrounding rock is about 40MPa after excavation. According to the analysis, it is considered that the strong deformation of surrounding rock of tunnel from the joint actions of very strong tectonic stress and vertical gravity stress; and that the soft fissured surrounding rock can not bear such actions, which causes continuous large rheological deformation. Engineering practice indicates that usual spouting concrete anchorage wall rock can not meet with the fissured surrounding rock stability under high stresses. Through the analysis of deformation mechanics of surrounding great significance to the reinforcement and repair rock and defects of prophase support system, this research finding is of of surrounding rock of iron mine.