大跨浅埋隧道采用台阶法施工的安全性评估

Safety Evaluation on Steps-Method Used for Large-Spanned and Shallow-Buried Tunnel

结合天际岭隧道大跨、浅埋、围岩条件差且工期紧的工程特点 ,采用数值计算与现场监控量测相结合的手段 ,对软岩隧道采取台阶法施工的安全性进行了分析评估。结果表明 :在遵循新奥法施工的基本原则 ,做到“短进尺、少扰动、勤量测、早封闭”的前提下 ,采用台阶法是可行的 ,能满足施工安全要求 。

in this paper, in reference to project characteristics of Tian Ji Ling tunnel: large-spanned, shallow-buried, soft surrounding rocks, time limit shortage, safety of steps-construction-method is analyzed and evaluated by numerical computation and measure in the spot. The results obtained show that if fundamental principles of NATM construction are followed as well as ”low driving rate, little disturbance, frequent measure, early closing ” can be reached, this method is really feasible, which not only meets safety demand but also prompts the rate of construction.