基于FLAC3D,建立了复杂断面隧道和建筑物的三维数值模型,以沉降量和结构应力最小为优化目标,对5种工法方案进行了优化,以确定最优工法.用最优工法开挖隧道,预测开挖引起的塑性破坏区,并提出有针对性的预加固措施.在对塑性破坏区进行预加固的条件下,预测各开挖段地表和建筑物基础的沉降特征及最大沉降量,对比分析地表沉降曲面与建筑物基础沉降曲面的差异,评价整个开挖过程中建筑物和隧道关键结构的安全性.数值模拟结果与实测数据规律一致,为复杂断面地铁隧道开挖的环境控制提供了重要的技术支持.%A 3D numerical model for complex cross-section tunnel and building was set up based on the FLAC3D, and five construction methods were optimized by numerical simulations to determine the optimal construction method by taking subsidences of ground surface and the building and stress in the structure as the optimal object. The optimal construction method was adopted to excavate the tunnel, plastic areas induced by excavation using the optimal construction method were predicted, and corresponding pre-reinforcement measures were given. The subsidence characteristics and maximum subsidences of ground surface and building foundation in different excavation periods under the condition of pre-reinforcement plastic areas were forecasted. The differences between the subsidence curved surfaces of ground surface and building foundation were comparatively analyzed. The safety of the building and key structures of the tunnel in the whole excavation process was evaluated. The simulations results and in-site measured data have the same regularities to provide an important technical support for environment control of metro tunnel excavation with complex cross-sections.
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