A dynamic assessment method on collapse risk of small spacing tunnels based on attribute interval recognition model

Due to the small thickness of the middle rock wall, the complex surrounding rock stress, and the great influence of construction, the large deformation and even the collapse of the vault are easy to occur in the small spacing tunnel. In order to more accurately assess the risk caused by tunnel collapse, combining with the case of a small spacing tunnel in the Puyan Highway in Fujian province, the evaluation index system and classification standard of tunnel collapse risk assessment were established based on the engineering topographic and geological conditions of highway tunnels. Moreover, the combined weights were used to calculate the weights of each evaluation index, and then the attribute interval recognition model was used to construct the dynamic risk assessment method of small spacing tunnel. Finally, the dynamic risk assessment method was used to evaluate the two dangerous tunnel sections in the tunnel section of the case. According to the evaluation results, the tunnel section X1 and X2 all have a high risk of tunnel collapse, which is consistent with the construction situation on site. It was verified that the evaluation results were reliable, which could be used for reference for similar projects.