Monitoring Method of Large Section Bifurcated Small Clear Distance Tunnel During Information Construction Control

Constructing a large section bifurcated small clear distance tunnel poses significant challenges due to its large section and small clear distance, complex and overlapping construction steps, unsynchronized excavation and support processes, and disturbance of surrounding rock caused by blasting. Timely and effective construction monitoring is crucial to ensure construction safety and quality. However, traditional monitoring methods are unable to fully satisfy requirements and realize real-time monitoring. Therefore, this study proposes an automatic monitoring and control method for a large section bifurcated small clear distance tunnel to leverage the positive role of information construction. Using the Xiamen Haicang Evacuate Channel project as a case study, this paper introduces the tunnel monitoring and layout scheme of monitoring points. The monitoring data were analyzed from different perspectives, including cumulative deformation, deformation rate, cumulative deformation control value, and deformation rate control value. The follow-up excavation and support measures were optimized based on the measurement results. Additionally, an automatic monitoring and control method of the middle rock pillar combined with the criterion of stability of the middle rock pillar was proposed, constructing a working idea and framework for timely feedback and three-dimensional and dynamic monitoring. Site monitoring predicted the danger before construction and provided feedback on construction information to improve the specific construction method of subsequent excavation and support. The proposed automatic monitoring and control method can solve the problem of accidental errors in traditional monitoring methods and enable real-time automatic monitoring. The research results provide valuable experience for constructing a bifurcated small clear distance tunnel.