| The fast development of city underground construction project inevitably leads to many construction projects of tunnels underpassing the existing buildings. And the process of underpassing tunnels’construction may have some risks, such as ground subsidence and uplift, surface buildings’ damage for dumping, underground pipelines’ deformation and failure, tunnels’collapse and so on. This paper presents a protection program that Shumuling tunnel in CZT Railway Line2underpassing Gaosheng hotel’ pile foundation, adopting the scheme comparison, theoretical analysis, numerical computation and field practice. The protection scheme is mainly as follows:(1)According to the engineering geologic conditions of the Shumuling tunnel underpassing the Gaoshen hotel in CZT intercity railway Line2, a protection scheme of pile-raft foundation underpinning has been presented by scheme comparison.(2) Through the three-dimensional numerical simulation, the safety of the pine-raft foundation underpinning was analyzed;and through making a comparison about the different tunnel construction method’s influence to the construction safety, a specific scheme for excavation and supporting has been presented..(3) A specific scheme and safety measures for the tunnel underpassing the Gaoshen hotel was proposed in this paper, which includes grouting reinforcement before construction of the raft, the fast closing in the process of the tunnel construction and the supplemental grouting between the raft foundation and tunnel vault. It guaranteed the safety of the surface building.(4) Pile foundation underpinning is a systematic project, a good construction management and informational execution is the key to success. Field monitoring and information feedback is an important method to guarantee the safety of the tunnel and surface buildings. Finally, the specific method of monitoring through field exercise has been discussed, which proved the reliability of the technology scheme. |
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