紧邻基坑同步施工下坑间隧道的变形特性

摘要：
采用非线性平面有限元方法研究紧邻基坑同步施工下坑间土体与隧道的变形特性.将该方法运用到上海某基坑工程中的隧道位移预测，实测数据与有限元结果比较吻合，验证了其可行性.通过参数分析，讨论了基坑之间的距离、开挖宽度对坑间土体竖向位移的影响，并由此推算出了使得坑间地表土体平均竖向位移接近零的最优基坑间距与开挖宽度的关系.同时讨论了盾构隧道、明挖暗埋隧道与基坑的距离对于隧道竖向位移、支护结构侧移的影响.研究表明，开挖完成后，坑间盾构隧道的沉降比周围土体的沉降略小，而有围护结构的明挖暗埋隧道则表现为上抬，距离基坑越远，上抬量越小.

Movement of Tunnel between Two Adjacent Concurrent Excavations

Closely constructed excavations will influence the stress and deformation of adjacent existing underground structures. In this paper, the non linear numerical analysis of plane finite element was applied to predict the movement of a construction of foundation pit in Shanghai to verify its applicability. Parametric studies were performed to investigate the influence of width of pits and the distance of the two pits on deformation of soil between two excavations. The relationship of optimal distance between excavations and the width of excavations was derived. The influence of the distance between the tunnel and the excavation on the deformation of tunnel was also analyzed. The results show that the settlement of shield tunnel is less than that of its neighboring soil. The shallow tunnel heaves during the excavation. The amount of heave is reduced for the tunnel more distant away from the excavation.