台东交叠隧道施工过程数值分析

Numerical Analysis of Excavation Process of the Overlapping Tunnels at Taldong Station of Qingdao City

对青岛市台东站近距离交叠隧道分别采用眼镜法和三台阶法施工时引起的地表沉降和上下隧道交互影响进行了三维数值仿真模拟研究。比较分析了在两种不同的开挖方式下,后期1#线隧道开挖引起既有2#线隧道衬砌的位移场和应力场的变化规律;发现由于后期施工隧道的干扰,使上部已完成的隧道断面有扭转变形趋势,衬砌断面上出现不均匀的拉压应力;确定了隧道开挖过程中衬砌容易破坏的部位、地表沉降漏斗的基本形状及其特征参数。研究还表明眼睛法施工优于三台阶法施工。模拟得到的结果为该工程设计、施工和监测提供了理论依据和技术指导。

The ground surface displacement and the interactions of the overlapping tunnels,which are settled in Taidong of Qingdao city and excavated separately by glasses method and tri - step method,were studied by the use of 3 - dimensional numerical simulation.The change laws of the displacement field and stress field of the liner of built tunnel 2#,under the excavation of tunnel line 1# by two different excavation ways mentioned above,were analyzed. Several conclusions were obtained as follows.Firstly,a twist trend of the former built tunnel was detected,which was caused by the construction of the later building tunnel.At the same time,the ununiformity of the tensile and compressive stress was found on the cross section of the liner.Secondly,several parameters were ascertained,such as:the position where damage occurred most easily,the basic geometry of the ground surface settlement funnel as well as its characteristic parameters.Finally,it was found that the glasses method has more advancement than the tri - step method.All of the results got from the imitation have been of fered as the theoretical reference and the technological guidance for the design,construction and monitoring of this engineering.