Factors affecting the deformation of the surrounding rock of tunnel based on rough set theory

Abstract

The deformation of surrounding rock is a common hazard in tunnel engineering, and it can negatively affect the quality and safety of a project. Therefore, the analysis of factors affecting the deformation of tunnels surrounding rock has essential engineering significance. This work selected two subjective factors affecting the deformation of the surrounding rock of a tunnel, namely, the excavation method and the excavation footage, and four objective factors (i.e., the tunnel burial depth, the degree of weathering, the groundwater conditions, and the uniaxial compressive strength of rocks) as the factors affecting the deformation of tunnel surrounding rock. Data on the factors influencing deformation of 25 typical deformation sections of the Tianqiao Mountain Tunnel under construction were collected to establish the condition attributes in the decision table. The actual deformation level was used as the decision attribute in the decision table. Rough set theory was used to perform a completely objective analysis of these six factors. Results of the analysis show that the groundwater conditions are the most influential factor in surrounding rock deformation with a weight of 0.3333, and the degree of weathering is a redundant factor. This study can be used as a guide for reducing or avoiding the deformation of the surrounding rock of a tunnel.