宜万铁路马鹿箐隧道进口泄水洞揭通溶腔施工技术

Techniques to Break through the Kasrt Cavity by Sluice Outlets in Maluqing Tunnel on Yichang-Wanxian Railway

在宜万铁路马鹿箐隧道施工中,出口平导PDK255+978处发生了溶腔突水、突泥的情况,造成了重大突发性工程地质事故。鉴于溶腔规模大、水压高、储水量和动态补给量大等地质条件,采取了地表钻孔封堵平导、在平导进口左侧20 m处增加泄水洞的优化施工方案;结合现场实际情况,尽早揭通溶洞,并采取了直墙平底断面型式、锚喷初期支护以及取消二次衬砌、取消围幕注浆和管棚、采用光面爆破、加强超前地质预报等措施,施工中取得了较好的效果。

Mud and water from a karst cavity poured into the parallel adit of Maluqing tunnel on Yichang-Wanxian railway at PDK255＋978. Considering the large scale of cavity, high water pressure, big storage and supply of ground water in the cavity, the parallel adit was blocked by drilling from the surface, an outlet was driven at 20m from the entrance of the parallel adit to break through the cavity. Other technical measures including smooth blasting and advance geology prediction were taken for the main tunnel construction.