Lining cracking mechanism of old highway tunnels caused by drainage system deterioration: A case study of Liwaiao Tunnel, Ningbo, China

•Crack patterns and water leakage mechanism of field tunnels are characterized.•Identified impact mechanism of deterioration of drainage system on tunnel lining.•Identified tunnel lining cracking mechanism using fracture-based numerical model.•A novel seepage water control measure using siphon drainage pipes is proposed.