A New Combined Support Technology to Prevent the Failure of the Existing Metro Station Induced by Unilateral Excavation

This study establishes a 3-D simulation model based on a real project, which reveals the problem that the metro structure deformation induced by unilateral excavation without any support exceeds the safety threshold. According to the metro structure deformation warning area, this study proposes a support technology that combines cover plate braces and diagonal steel braces. The research shows that the lateral deformation reduction ratio of the metro station under the diagonal steel brace is about 10% – 20%. The deformation reduction ratio under the cover plate brace is about 35% – 40%. To ensure construction safety, this study adopts the optimal support combination of 3 cover plates and 6+9+11 steel pipes. Monitoring feedback and simulation prediction shows that the comprehensive support system can reduce structural deformation by 56.1%, and effectively control the deformation within a safe range.