Failure behavior and reinforcing design of degraded tunnel linings based on the three-dimensional numerical evaluation

•Comprehensively investigate the effect of voids on the three-dimensional distribution of the inner force of tunnel linings.•Focus on plastic failure behavior and stress distribution of degraded tunnel linings.•Quantitatively explore the reinforcing effect of the FRP-PCM method on the tunnel structure with void diseases.•Discuss the potential cracking zone of tunnel linings with void diseases.