Prediction of the Surrounding Rock Deformation Grade for a High-Speed Railway Tunnel Based on Rough Set Theory and a Cloud Model

With the continuous progress of the Chinese social economy, the construction of high-speed railways has been increasing in China. The deformation grade of surrounding rock plays an essential role in construction safety for high-speed railway tunnels. Therefore, predicting the deformation grade of surrounding rock during tunnel construction is of great significance. This paper takes the Zheng-Wan high-speed railway tunnel as the research object, and the Delphi method and cloud model theory are used to study the deformation of the rock surrounding the tunnel. The grade standard of the surrounding rock deformation for a high-speed railway tunnel is established, and the key factors affecting the deformation grade of the surrounding rock are analyzed. Then, rough set theory is used to obtain the weight of each influencing factor; in the weight calculation results, the occurrence of geological discontinuity and groundwater content account for the greatest weights, which are 0.42857 and 0.28571, respectively, in line with engineering practice. Finally, a model for predicting the deformation grade of surrounding rock is established by using cloud model theory, and the model results are compared with actual observations during tunnel excavation. The results show that this model offers effective operability, a high accuracy and an important value to engineering applications and guarantees tunnel safety during construction.