地面堆载作用下既有隧道的工作状态

随着城市的快速发展，在既有盾构隧道周边地块的开发利用过程中，进行地面堆载是不可避免的，为评估地面堆载对隧道结构安全的影响，以区间盾构隧道为工程背景，首先，采用等效轴向刚度模型理论计算得出隧道变形界限值；其次，采用ABAQUS数值模拟软件，以隧道下卧软土层为地层条件建立三维实体数值模型，分析不同堆载范围和不同堆载大小对隧道结构纵向变形曲率、环缝张开量以及螺栓应力的影响；最后，将计算结果与隧道变形界限值进行对比，判定结构是否安全，并依此划分隧道的工作状态。研究成果对软土地区盾构隧道的结构设计和安全保护具有重要意义。

Working State of Existing Tunnel Under Ground Surcharge

With the rapid development of the city, it is inevitable to carry out ground surcharge in the progress of development and utilization of the surrounding blocks of the existing shield tunnel. In order to evaluate the influence of ground surcharge on the safety of tunnel structure, the shield tunnel of a certain section of a certain line is taken as the engineering background. Firstly, the equivalent axial stiffness model is used to calculate the boundary value of tunnel deformation. Secondly, the ABAQUS numerical simulation software is used to establish a three-dimensional solid numerical model with the soft soil layer under the tunnel as the stratum condition. The influence of different surcharge ranges and different surcharge sizes on the longitudinal deformation curvature, ring opening and bolt stress of the tunnel structure is analyzed. Finally, the calculation results are compared with the tunnel deformation limit value to determine whether the structure is safe, and the working state of the tunnel is divided according to this. The research results of this paper are of great significance to the structural design and safety protection of shield tunnels in soft soil areas.