Risk assessment of shield tunnel in composite strata based on BIM and efficient numerical analysis technology

The risk assessment of shield tunnel linings in composite geological formations presents critical challenges for infrastructure safety and maintenance. This study develops an innovative framework integrating Building Information Modelling (BIM) with numerical analysis to enhance risk evaluation processes. A BIM-based secondary development was proposed to realise the one-click generation of supporting structures. Subsequently, a sophisticated numerical pretreatment method was developed to accurately calculate spring stiffnesses and automate the installation of spring elements. Based on the refined models and efficient numerical analysis method, investigations on the mechanical and deformation responses of the lining segments within the three-layered composite strata were conducted, and then, the risk location and classification were discussed. Results show that: (1) the proposed technologies provide robust tools for risk assessment of the lining segments. (2) The instability of the lining segments appears by tensile concrete cracks, which distribute inward and outward near the segmental joints and within the soft layer, respectively, leading to cracking and leakage risks. (3) The dip angle and the thickness of the soft layer are key factors affecting the instability risk of the lining. These findings provide valuable insights for the design and optimisation of linings in complex geological conditions.