软弱地层隧底群桩加固下隧道洞室开挖方法对比研究

Comparative Study on Different Methods for Tunnel Excavation of Group Pile Reinforcement for Tunnel in Soft Strata

针对贵阳龙洞堡机场综合枢纽软弱地层段隧道工程,采用数值模拟,开展了隧底群桩加固下隧道洞室台阶法、CD法、CRD法等3种开挖方法的对比研究,主要对比分析了不同开挖方法下地表、地中、拱顶、拱底位置处的位移与应力,以及洞周锚杆和隧道衬砌的内力。研究结果表明:CRD法能较好控制地表与拱顶的沉降,台阶法施工锚杆的轴力较大,CD法和CRD法在监测的各个部位的弯矩变化值较大,台阶法在监测的各个部位的弯矩变化幅度较小。

Based on Guiyang Longdongbao airport tunnel process which is built of group pile reinforcement in soft strata, this paper,by numerical analysis,compared and analyzed the differences in benching tunneling method, CD method and CRD method which were based on group pile reinforcement. The displacement and stress of the surface, the ground, the vault and the bottom of the arch, the bolt and the internal force of tunnel lining under different excavation methods are compared and analyzed. The results show that the CRD method controls the settlement of the surface and the vault is better. The axial force of the bolt of benching tunneling method is larger, the bending moment of the CD method and the CRD method at each part of the monitoring is larger. The bending moment of the benching tunneling method at each part of the monitoring is smaller.