越江隧道联络通道冻结施工三维数值分析

3-D Numerical Analysis of Connected Aisle Construction in Cross-river Tunnel with Artificial Ground Freezing Method

文章采用三维有限元分析方法,对运用冻结法修筑某越江隧道联络通道的全过程进行了模拟。研究结果表明:(1)冻胀力对冻土帷幕和主盾构隧道影响显著,应考虑实施低温快速冻结以减小冻胀量;(2)联络通道和泵房开挖后,冻土帷幕稳定性大幅削弱,拱顶位置及泵房底部与侧壁连接处是薄弱点;(3)联络通道底板和泵房侧壁初期支护拉应力较大,可考虑在原设计方案上加强;(4)补偿注浆可有效降低因融沉产生的结构差异变形;(5)当冻胀率控制在3%左右时,施工安全可得到保证,实际施工中可根据变形监测结果推出实际冻胀率。

The entire process of connected aisle construction in a cross-river tunnel with artificial ground freezing method is simulated by using 3-d finite element method. The results show that ： （ 1 ） Frost heaving force has significant effect on the frozen soil and the shield tunnel, rapid freezing may reduce the amount of frost heaving ; （2） After the excavation of the connected aisle and the pumping station, the stability of the frozen soil is deeply declined, areh top position and the junction of pumping station bottom with the wall are weak points ; （3） The tensile stress of initial support in the bottom of the connected aisle and the pumping station wall is high, original design should be strengthened; （4） Compensation grouting can effectively reduce the differential deformation produced by thawing; （5） When frost heave rate is below 3%, the construction safety is assured, the actual rate in construction can be figured by deformation monitoring results.