ABSTRACT
Nowadays, with the rapid development of the economy, the constructions of the tunnels in congested urban area are increasing. Therefore, many new tunnels will be excavated near the existing underground structures. Based on a project in Shanghai, this study conducted the 3D numerical analysis to investigate the soil displacement induced by the construction of the tunnel in limited space which was formed by the existing underground infrastructures. To enhance the understanding of close-proximity tunneling, the integrated numerical models of the construction of shield tunnel in limited space and the construction of shield tunnel in half-infinite space were established, respectively. The results revealed that the soil in the limited space was disturbed significantly. The maximum ground subsidence and the range of ground settlement induced by the construction of tunnel in limited space were 60% and 50%, respectively, smaller than those induced by construction of tunnel in half-infinite space. The ground settlement patterns under these two circumstances were almost the same. Moreover, a soil settlement trough appeared below the bottom slab of the underground structure. The findings can provide a better understanding of the soil displacement induced by tunnel excavation in limited space in soft clay stratum and can offer the guidance for the similar projects.
