为提高强震区含病害铁路隧道的安全性，通过隧道检查车对29座高速铁路隧道衬砌背后空洞测试，借助有限差分方法研究空洞对隧道结构安全性的影响。结果表明：高铁隧道衬砌背后空洞极易出现在拱顶，占比80.00%；空洞纵向长度出现频率最高区间为2 ~ 4 m，占比46.49%；与衬砌表面最小距离为0.3 ~ 0.55 m的空洞占比78.93%，空洞常伴随衬砌厚度不足病害；衬砌背后空洞改变围岩-支护的接触状态，进而结构的惯性力和强制位移改变，震时位移和应力状态也随之变化；空洞导致所在部位的结构内力改变，结构安全系数降低19.51% ~ 95.27%；随着空洞的环向角度、径向深度、纵向长度的增加，结构安全系数降低。衬砌背后空洞将导致高铁隧道衬砌的震时安全性显著降低。研究成果可为含病害高铁隧道抗震设防提供借鉴。

To enhance the safety of railway tunnels with diseases in high seismic areas, a tunnel inspection vehicle was used to test 29 high-speed railway tunnel linings for voids behind them. The influence of voids on the safety of tunnel structures was studied using the finite difference method. The results indicate that voids behind the lining of high-speed railway tunnels are prone to occur at the arch crown, accounting for 80.00% of occurrences. The most frequent range of longitudinal length for voids is from 2 m to 4 m, representing 46.49% of occurrences. The minimum distance between voids and the lining surface is mainly distributed in the range of 0.3 m to 0.55 m, accounting for 78.93%. Voids are often associated with defects in the thickness of the lining. Voids behind the lining alter the contact state between the surrounding rock and support, leading to changes in the inertial force and forced displacement of the structure. Displacement and stress states subsequently change. Voids result in changes in the internal forces of the structure in their respective locations, reducing the safety factor of the structure by 19.51% to 95.27%. As the void's circumferential angle, radial depth, and longitudinal length increase, the safety factor of the structure decreases. The cavity behind the lining will significantly reduce the seismic safety of high-speed railway tunnel lining. The research findings can provide a reference for seismic defense measures for high-speed railway tunnels with defects.