Evaluation of construction impacts and optimization of control measures for large-section metro tunnels overpassing existing tunnels

The development of urban rail transit has led to an increase in the number of large section subway tunnels crossing existing tunnels. This study combines the actual engineering of the Yanggongqiao Station Longzhuayan Station section tunnel of Chengdu Metro Line 17 Phase II project crossing the existing Line 7 shield tunnel, and uses on-site investigation, monitoring, and numerical simulation methods to evaluate the construction impact. Based on this, measures such as bench pile reinforcement, pre grouting, and parameter optimization are proposed. In practical applications, the comparison between monitoring and simulation results shows that these measures effectively control the deformation of existing tunnels, providing important references for similar projects.