深部高应力软岩巷道变形破坏原因及支护技术

Deformation reasons and support technology of deep and high-stress soft rock roadway

为解决深部高应力软岩巷道支护难题,以九龙矿-850轨道大巷为工程背景,采用现场调研、矿物成分分析和围岩结构窥视等方法,揭示了围岩变形破坏原因,得出工程地质条件差、围岩非均匀变形显著、支护结构工作阻力低、围岩承载能力难以发挥是造成巷道支护失效和变形失稳的主要原因。基于上述研究,提出以"协调围岩非均匀变形、控制挤压流动底鼓、强化围岩承载结构"为核心的联合支护方案。即以强力锚杆、高预应力锚索为基础,在巷道薄弱部位增设锚索实施非对称支护协调围岩变形,采用槽钢梁式桁架锚索加大底板支护强度控制底鼓,及时喷射混凝土层和架设U型钢使表面围岩均匀受压,最后全断面壁后注浆强化围岩承载结构,实现分层次协同承载。数值模拟和现场监测表明,该支护方案可有效控制深部高应力软岩巷道变形,使支护一次到位,避免多次返修。

To solve the roadway support problems in high-stress and soft surrounding rock, based on the -850 track roadway in Jiulong coal mine, the field research, the mineral composition analysis, the tests of rock structure and etc. have been employed to investigate the deformation reasons of surround-ing rock. The results show that the main reasons resulting in the supporting failure and deformation in-stability are the poor environmental geological settings, dramatically non-uniform deformation of sur-rounding rock, low working resistance of supporting structure and poor bearing capacity of surrounding rock. Based on such results, a combined supporting technology concentrating on coordinating the non-uniform deformation of surrounding rock, controlling squeeze flow floor heave and strengthening the bearing structure of surrounding rock is proposed. This support technology is based on the high strength bolts and pre-tensioned anchor cables： adding anchors in the weak parts of the roadway to implement asymmetric support to coordinate the surrounding deformation, employing the channel steel girder truss anchor cable to control floor heave by strengthening the support, spraying the shotcrete layer and erect-ing U-shaped steel in time to make the surface of the surrounding rock uniform compression, and finally, grouting on the whole section to strengthen the bearing structure of surrounding rock and to achieve the hierarchical cooperative bearing. The numerical results and field measurements indicate that this support technology can control the roadway deformation in the deep, high stress and soft surrounding rock which can avoid further repairing.