佛岭长大隧道洞口段施工方案优化研究

Research on Design Optimization of Construction Method in Entrance of Foling Long and Large Tunnel

绩黄高速佛岭长大隧道洞口段存在埋深浅、围岩自稳能力差的特点,采用FLAC3D程序对拟定的预留核心土法、CD法、中隔壁法(CRD)和单侧壁导坑法、双侧导坑法,进行了施工过程的三维数值模拟。以不同方法施工过程中的围岩变形、塑性区体积和支护材料用量作为考察指标,经过技术和经济综合比选,最终确定采用单侧壁导坑法为最优工法,为佛岭隧道洞口施工提供了指导。

Due to shallow embedded depth and bad self-stabilization capability of surrounding rock in entrance of Foling Long and Large Tunnel of Jihuang Expressway, one of prepared core soil method, CD method,CRD method, single side heading method and twin-side heading method is selected as the excavation method in this segment. In order to choose the optimal excavation from above five methods, the construction process is simulated in three dimension by the FLAC3D software in this paper. Deformation, plastic zone volume of surrounding rock and consumption of supporting material by different excavation method are considered as the judge index. Last, the single side heading method is determined as the optimal excavation method through technical and economical analysis and the guidance for construction in entrance of Foling Tunnel is provided.