盾构隧道下穿建筑物变形控制及预测研究
Study on Control and Prediction of Building Deformation through Shield Tunnel Crossing Buildings

随着城市化进程的加快，城市地铁隧道日益增加，隧道下穿越建筑物的情况日益增长。当盾构隧道下穿越建筑物时，容易导致地表的过度沉降，进而影响周围建筑物的不均匀沉降造成建筑物开裂甚至发生倒塌。本文主要分析了隧道施工对建筑物的影响方式和扰动控制指标，并以常州轨道交通2号线红梅公园站–五角场站下穿越建筑物为例，分析了利用MIDAS/GTS NX进行数值模拟，分析不同类型建筑物在隧道开挖过中的沉降变化，得到了如下结论：1) 隧道施工对建筑物的影响方式主要包括地表不均匀沉降、地表曲率变化和地表水平变形三类；2) 在隧道施工过程中，土体受施工扰动的主要控制因素包括应力状态的改变、含水量及孔隙比的变化、土体结构性部分破坏和化学成分分离与混合四类；3) 本工程隧道下穿越建筑物时，随着离隧道中线距离增加，沉降减小，而隆起逐渐增加，在整个开挖过程中，地表变形呈现隆起–沉降–稳定的三阶段变化。
With the rapid development of urbanization, the number of subway tunnels in the city is increasing. When the shield tunnel across the building, it is easy to lead to the excessive settlement of the ground, which will affect the uneven settlement of the surrounding buildings and cause the building cracking or even collapse. This paper analyzes the influence mode and disturbance control index of tunnel construction on buildings. Taking Changzhou Metro Line 2 which crosses the buildings as the engineering background, and uses MIDAS/GTS NX for numerical simulation to analyze the settlement of different types of buildings during the tunnel excavation, the following main conclusions can be drawn: 1) The influence of tunnel construction on buildings mainly includes surface uneven settlement, surface curvature change and surface horizontal deformation; 2) During tunnel construction, the main controlling factors of soil disturbed by construction include the change of stress state, the change of water content and pore ratio, the failure of soil structure and the separation and mixing of chemical components; 3) In this project, when the tunnel across the building, the settlement decreases with the distance from the middle line of the tunnel increasing, while the uplift increases gradually. During the whole excavation process, the surface settlement shows three stages of uplift, subsidence and stability.