Numerical simulation of deformation influence of foundation pit excavation on shield tunnel under support structures

Abstract

With the rapid development of the times, urban underground space engineering is more widely used, and the construction of deep foundation pit excavation will inevitably affect the shield tunnel under the support structure. Based on a large deep foundation pit support project in Zhuhai, this paper uses Midas GTS three-dimensional numerical simulation calculation software to analyze different width and thickness arrangements of foundation pit reinforcement area and the regularity changes of influence of foundation pit excavation on the deformation of the support structure and shield tunnel. The main conclusions are as follows: the thickness of the foundation pit reinforcement area increases compared with the width, which has a more obvious protection effect on the foundation pit support structure and shield tunnel. And when the width of the reinforcement area is increased to a certain value, the protection effect for the shield tunnel will decrease after 39m of this project. The comparison between the corresponding simulation data and actual monitoring data shows that the research results of this paper can provide a reference for other similar projects in deep soft soil areas.