黄土隧道洞口浅埋段开挖支护技术探讨

Discussions on Excavation Support Technology in Shallow-buried Portal Segment of Loess Tunnel

随着国家西部大开发的不断深入,铁路隧道施工中黄土隧道所占的比例逐步提高。文章以兰山隧道工程实例为背景,介绍了该隧道洞口段的总体施工方案,并针对在施工过程中出现的沉降过大导致衬砌裂缝及地表裂缝的问题,提出采用反压墙控制边坡滑移、仰拱紧跟及三台阶临时仰拱法控制隧道拱部沉降等一系列保证黄土隧道洞口浅埋段施工安全的开挖支护技术措施,以便为今后同类型隧道的施工提供参考。

With the further deepening of Chinas Western Development,the proportion of loess tunnel in railway tunnel construction is gradually increasing.Taking the practical Lanshan Tunnel engineering example as the background,this article introduced the overall construction plan of entrance segment in this tunnel,and for the lining cracks and surface cracks caused by large settlement during the construction,it proposed the use of slope slippery control by back-pressure wall,tunnel arch subsidence control by inverted arch close-following and three-step temporary inverted arch method,and other excavation and support technology measures to ensure the construction safety of shallow-buried portal segment of loess tunnel,so as to provide reference for the construction of same tunnels in future.