营尔岭隧道浅埋段连续坍塌原因分析及预防

双侧壁导坑法是现有大断面隧道施工方法中最为理想的一种方法。以某隧道浅埋段连续坍塌为例,通过MIDAS/GTS NX有限元软件对较大断面侧壁导坑上台阶开挖时出现连续坍塌事故进行了分析,并对添加临时仰拱这一措施对改善支护结构稳定性及预防坍塌发生的效果进行验证。浅埋条件下,初期支护结构未得到有效封闭连接是引起侧壁导坑上台阶开挖时出现连续坍塌的主要原因,施做临时仰拱能够有效防止坍塌的发生,这一结论对具有相似条件的工程具有借鉴意义。

Continuous Collapse Cause Analysis and Prevention for Shallow Buried Section of Yingerling Tunnel

Double side drift method as the most ideal method has always been applied to construction of large cross-sec-tion tunnel .Taking an example of continuous collapse in shallow buried section of a tunnel ,by adopting Midas GTS NX finite element software this paper analyzed an accidence of continuous collapse which appeared during the excavation of a larger cross-section side drift and verified the stability improvement of the retaining structure and the effect of preventing the occurrence of the collapse by adding temporary inverted arch .The results show that under shallow burial conditions , the main reason leading to continuous collapse is considered that the initial supporting structure is not effectively closed when excavating side drift upper steps .The occurrence of collapse can be prevented effectively .by making temporary in-verted arch .