鹤上大断面小净距隧道施工方案优化分析

Optimal analysis of construction schemes for Heshang small-space tunnels with large section

结合福州国际机场高速公路鹤上大断面小净距隧道工程实际,建立了大断面小净距隧道施工动态有限元分析程序,对隧道施工方案的优化进行了数值模拟分析。分析中模拟了双侧壁导坑法、中隔壁法和上下台阶法3种施工方案,对拱顶下沉、地表沉降、中间岩柱应力、围岩稳定性等进行了对比分析,并结合鹤上隧道围岩实际情况,在隧道出口Ⅴ级围岩段,改双侧壁导坑法为中隔壁法,顺利完成了施工,对降低施工成本、加快施工进度均起到了较好的作用,研究结果可为类似条件下大断面小净距隧道的设计、施工提供借鉴与参考。

According to the construction conditions of Heshang small-space tunnels with large section in Fuzhou International Airport Expressway, a finite element analysis program is established to simulate the construction process. In the program, the double-heading construction method, middle wall construction method and benching tunneling method have been simulated; and the settlements of vault and ground, stress of the interspace rock and stability of the surrounding rock are analyzed and compared; then the advantages of the three methods are compared. Considering the characteristics of Heshang Tunnel, the practical construction scheme is optimized. The experience and conclusions can be for reference in the design and construction of similar tunnels.