胶州湾海底隧道不对称双连拱断面施工优化分析

Research on construction optimization of asymmetric double-arch section in Jiaozhou Bay Subsea Tunnel

以青岛胶州湾海底隧道中的不对称双连拱隧道为工程背景,选取主隧道与匝道交叉口段的典型断面建立数值计算模型,针对不同的施工开挖顺序和掘进进尺制订了4种施工方案,并采用有限差分软件FLAC3D进行动态施工的三维数值模拟,计算分析并比较各方案的地表沉降、拱顶沉降和支护结构位移以及围岩应力和支护结构应力的分布情况,明确不对称双连拱隧道施工中结构变形及应力的最不利位置。分析结果表明,先施工中导洞再施工匝道断面右导洞并采用小进尺的施工方案更有利于控制围岩的稳定性,并据此提出了合理的施工方案建议。

Aiming at the asymmetric double-arch tunnel engineering that lies at Jiaozhou Bay in Qingdao, the section located in the intersection between main tunnel and ramb tunnel is chosen as a typical cross section and a three-dimensional model for numerical analysis. Four Construction schemes are constituted according to different construction sequences and different digging lengths. Then these schemes are simulated with FLAC3D program. By analyzing ground surface settlement, vault settlement values, displacement of supporting structure, principle stress in surrounding rock, as well as principle stress in supporting structure, the most disadvantage position of structural deformation and stress during construction is determined. It concludes that the surrounding rock deformation could be better controlled by using of the construction sequence that first middle drift and then right hole of ramb tunnel, and the reasonable construction scheme is suggested