宜万铁路别岩槽隧道F3断层突发性涌水治理

TREATMENT OF BURST WATER ON FAULT F3 OF BIEYANCAO TUNNEL ON YICHANG-WANZHOU RAILWAY LINE

研究目的:宜万铁路别岩槽隧道F3断层围岩破碎,为碎石土,局部溶隙、溶槽发育,有少量地下水,施工中按V级围岩采用超前小导管支护、格栅钢架支撑、网喷混凝土,采取台阶法开挖。在初期支护完成3个月后,由于受地表强降雨影响,致使隧道线路右侧暗河(距隧道约10-20 m)水量增大、水压升高,继而导致隧道初期支护严重开裂-变形,突发大规模涌水。本文主要分析了F3断层突发性涌水机理,介绍了F3断层突涌水的治理措施。研究方法:突发性涌水后,现场立即启动应急预案,在安全监视下,采取工字钢环向加固和横向支撑,并对线路右侧边墙进行钻孔放水泄压。水量稳定后,对F3断层段采取径向加固堵水注浆;拆除变形格栅钢架,采用 I20钢架替换;并及时施作二次衬砌。研究结果:通过采取“径向注浆加固-初期支护加强-及时施作二次衬砌”等综合技术措施,F3断层治理后,仅在局部位置出现渗流水,水量1 m3/h,治理效果良好。研究结论:(1)通过别岩槽隧道F3断层涌水事故,当隧道周围(不超过100m)存在暗河通道等赋水条件, 隧道开挖揭示围岩破碎,那么,既使隧道开挖中未发生涌水,也难以保证初期支护完成后不发生涌水事故,甚至很难保证隧道完成后运营过程中不出现问题,随着“强本简末,为运营服务”隧道修建理念的提高,针对类似地质构造,做到提前防范,加强处理。(2)针对类似别岩槽隧道F3断层地质特点,采取径向注浆是一种有效的治理及防范措施。

Research purpose： The surrounding rock of Fault F3 of Bieyancao Tunnel on Yichang-Wanzhou Railway Line is broken up. The fault is of gravely soil with local developments of solution crack and fluid bowl, and a little underground water. According to the standard of surrounding rock V Grade, the prevention and support are conducted in advance for the surrounding rock by small pipe, grid steel frame and net spraying concrete, and bench excavation is adopted during sonstruction. Three months later of primary prevention and support, the support for the tunnel is seriously cracked and deformed, and water is burst by large scale because of increments of water volume and water pressure in underground river on right side of railway line （10-20 m far from tunnel）, caused by heavy rain. The analysis is made of mechanisation for burst water on Fault F3 and an introduction is given to treatment measures for the gushed water in this paper. Research method： After occurrence of burst water, the following emergency measures are taken on site. Toroidal reinforcement and lateral support are conducted by I-steel, and holes are drilled on right side wall to drain water and decrease water pressure, After stabilization of water volumen, the radial reinforcement is conducted for Fault F3 by grouting to block water. The deformed grid steel frames are displaced by steel frame I20 and secondary lining is laid in time. Research result： After treatment by adopting technical measures of ＂radial grouting reinforcement-primary support reinforcement-laying secondary lining＂, only local vadose water occurs on Fault F3 with water volume of one cubic meter per hour. The treatment result is good. Research conclusion： First, it is known from burst water accident if the watery situation of underground river occurs around tunnel （within 100 meters）, once the surrounding rock breaks up, even water is not burst during tunnel excavation, but it is difficult to ensure no occurrence of burst water after ending primary support or no occurrence of problems in service of tunnel. With concept increment of ＂Strengthen the foundamental and weak the trivial, and service for operation＂ for tunnel construction, it is necessary to reinforce in advance and make provisions before troubles occur to such geological structure. Secondly, it is an effective way to treat and prevent occurrence of burst water in similar geological structure of Fault F3 of Bieyancao Tunnel.