超深地下立交分期实施措施及影响分析

Analysis on Phased Implementation Measures and Impact of Ultra-deep Underground Interchange

摘要:

采用 MIDAS GTS 建立三维数值分析模型，对已建隧道附近的深大基坑开挖和封堵墙拆除施工工况进行模拟。结果表明：深大基坑开挖会引起已建立交匝道隧道向坑内变形，施作多道混凝土支撑结合地基加固，能较好地控制变形；同时，采取施加钢支托方案拆除既有围护封堵墙，可以有效控制基坑变形，稳定基坑支撑受力。在拆除既有围护封堵墙过程中，新加钢支托的受力变化幅度较大，应采取可靠的实时监测措施。

Abstract:

MIDAS GTS is used to establish a three-dimensional numerical analysis model to simulate the construction conditions of deep foundation pit excavation and blocking wall removal. The results show that the excavation of deep and large foundation pit will cause the deformation of the built interchange ramp tunnel into the pit. The deformation can be well controlled by using multiple concrete supports combined with foundation reinforcement. At the same time, the existing retaining and blocking walls can be removed by adopting the steel support scheme, which can effectively control the deformation of the foundation pit and stabilize the stress of the foundation pit support. During the removal of the existing retaining and blocking walls, the stress of the newly added steel support varies greatly, and the reliable real-time monitoring measures should be taken.