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在多层多种地下结构相互作用的复杂环境中,新建隧道施工侵入到地下街群桩基础的内部,具有较高的工程风险。通过数值模拟与现场实测,重点研究新建隧道侵入过程对地下街桩位移与内力的影响。结果表明:开挖正洞下部会使与导洞初衬底板相交处的桩段弯矩急剧增大;截桩后,置于正洞上拱部衬砌中的残留桩段轴力明显减小,而衬砌的最小主应力明显增大;与不存在地铁隧道时相比,附近存在地铁隧道时的新建隧道施工引起的地下街桩基沉降会减小,应考虑第三方地下结构的作用。该研究结论可为新建隧道穿越复杂地下结构体系的灾害预防提供参考。
In the complex environment with multi-storey and multi-underground structures interacting, the construction of new tunnels intrudes into the foundation of pile foundation in underground shopping streets, which has high engineering risk. Through numerical simulation and field measurement, the impact of new tunnel invasion process on the displacement and internal force of underground stakes is studied emphatically. The results show that the bending moment of the pile segment intersecting with the original lining of the guide tunnel increases sharply when excavating the lower part of the normal hole. After cutting the pile, the axial force of the residual pile placed in the lining of the upper arch of the normal tunnel decreases obviously, While the minimum principal stress of lining increases obviously. Compared with the case without metro tunnel, the settlement of underground pile foundation caused by the construction of new tunnel in the presence of subway tunnel will be reduced, and the effect of the third-party underground structure should be considered. The conclusions of this study can provide reference for disaster prevention of new tunnels crossing complex underground structures.