高速铁路岩溶隧道大型溶洞综合勘察及处理技术研究

Study on Comprehensive Investigation and Treatment Scheme of Large Cave in High-speed Railway Karst Tunnel

岩溶隧道的大型溶洞勘察及处理方法是高速铁路设计施工的难点,张吉怀铁路兰花隧道施工中揭示了大型溶洞,为确保铁路安全,需详细查明溶洞工程地质特性及水文地质特性,并确定合理的溶洞处理方法。通过地质调查、钻探及物探等综合勘察技术,详细查明了溶洞群的规模、相互关系及隧底岩溶发育情况。综合勘察结果表明:Ⅰ号溶洞底部至暗河间分布充填型溶洞及溶蚀性灰岩;Ⅱ号溶洞为受垂直节理控制发育的垂直型岩溶通道的一部分,为竖向过水通道;Ⅲ号溶洞对铁路工程无直接影响,但其靠近Ⅰ号溶洞,局部岩盘厚度仅2 m;溶洞群地下水径流方向为隧道底部自左向右。根据溶洞发育规模、工程及水文地质条件,经综合分析确定,该溶洞采取溶洞底预留过水通道、回填混凝土的处理方案。

The investigation and treatment of large-scale karst caves in karst tunnels are the key technologies for the design and construction of high-speed railways.To ensure railway safety,the large-scale karst caves encountered in the construction of the Lanhua Tunnel on the Zhangjiajie-JishouHuaihua Railway require detailed investigation of the engineering geological and hydrogeological characteristics and reasonable cave treatment method.With comprehensive survey techniques such as geological survey,drilling and geophysical prospecting,the scale and relationship of the cave group and the development of karst at the bottom of the tunnel are investigated in detail.The comprehensive survey results show that filling karst caves and soluble limestone are distributed from the bottom of No.1 cave to the underground river;No.2 cave is a part of the vertical karst channel developed under the control of vertical joints,which serves as a vertical water passage;No.3 cave has no direct impact on the railway project,but it is close to No.1 cave and the thickness of the local laccolite is only 2 m;the direction of groundwater runoff in the karst cave group is from left to right at the bottom of the tunnel.According to the development scale of the karst cave,engineering and hydrogeological conditions,it is determined,through comprehensive analysis,to employ the treatment plan of reserving water passage at the bottom of the karst cave and backfilling concrete.