A 3D Finite Element Analysis and Field Monitoring of the Residual Displacement of the Existing TBM Tunnel After Underground Culvert Construction: A Case Study in Ho Chi Minh City

The continuous development of underground space has been creating complex intersections between projects, special with existing subway tunnels. In addition to managing risks during construction, ensuring safety for existing underground tunnel projects is also an important issue in the engineering field. This article is based on a real situation in Ho Chi Minh City, where the construction of an underground culvert is above the existing TBM subway tunnel of Metro Line 1, from Ben Thanh to Suoi Tien. The residual displacement of the tunnel after the construction of the underground culvert is evaluated using results from a 3D finite element model in conjunction with field monitoring. The analysis results indicate that the residual displacement falls within permissible limits, with the values obtained from the model being approximately 30% higher than the field monitoring. The results from the model ensure the safety of the initial assessment of the structure's displacement, and when combined with field monitoring, they help establish a correlation between them. This correlation will ultimately optimize the quantity of measurements taken.