新建贵广高铁坪山岩溶隧道设计与施工

Design and Construction of Pingshan Karst Tunnel on New Guiyang-Guangzhou High Speed Railway

新建贵阳至广州高速铁路坪山隧道位于广西溶蚀中低山区,岩溶不良地质发育,施工风险较高。为确保隧道的施工及运营安全,本文基于隧道所处水文地质条件,分析了勘察和施工过程中可能存在的风险,提出隧道超前地质预报或施工揭示岩溶后应根据各岩溶地段不同的地质特征逐段进行整治;出现地表塌陷坑的地段采取地表水引流、回填陷坑、袖阀管注浆加固等措施,同时要加强对洞顶地表易受洞内坍塌影响范围的监测;隧道底部为岩溶填充物且填充物局部呈软塑状态,充填深度较小地段隧底基础采用混凝土换填,充填深度较大地段隧底基础采用微型桩加固。

The Pingshan tunnel of newly built Guiyang-Guangzhou high speed railway is located in the middle-low karst mountain area in Guangxi Province. In this area,the geological development of karst is bad,t he construction risk is very high.In order to ensure the construction and operation safety of tunnel,o n the basis of hydrogeological conditions of tunnel,t he possible risk in the process of exploration and construction were analyzed.The karst area was revealed by the geological prediction or construction of tunnel,then the tunnel should be treated by segments according to different geological characteristics of the karst areas. The area with surface subsidence was treated by using lots of methods, such as surface water drainage,pit backfill, sleeve valve pipe grouting reinforcement.At the same time,the influence range of surface easily to cave collapse should be monitored closely.The tunnel bottom is karst filler,and the local filler is in soft-plastic state.In the area of smaller filling depth,the tunnel bottom foundation should be replaced by concrete, in the area of larger filling depth,the tunnel bottom foundation should be reinforced by micro-pile.