Studies show that lining cracks are one of the most common anomalies that occur in the operational tunnels. Therefore, investigating the performance of the cracked linings is of significant importance during the tunnel maintenance. In the present study, model tests and numerical simulations are performed to investigate the influence of the longitudinal cracks at the invert on the mechanical behavior of the tunnel linings. Obtained results show that (1) the pre-existing cracks at the invert aggravate the crushing failure at the back of the fracture zone, leading to the brittle instability of the tunnel; (2) the deformation process of the cracked tunnels initially develops linearly up to a drastic increase. Moreover, the magnitude and the growth of the deformation at the damaged area of cracked linings before the abrupt failure are larger than those of the intact linings; (3) the cracks result in a distinct decrease in the bending moment at the damaged area, whereas the thrust force is less sensitive to the number of cracks; (4) the pre-existing cracks in the invert weaken the lining's ability to resist the pressure of surrounding rock and increase the share of the arch foot in the contact pressure; (5) the pre-existing cracks at the invert reduce the bearing area of linings, thereby weakening the flexural stiffness and favoring the crushing failure at the invert, which is the main reason for the decrease in the bearing capacity of the cracked tunnels.

研究表明，衬砌裂缝是运营隧道中最常见的异常之一。因此，在隧道维护过程中，调查破裂衬砌的性能非常重要。在本研究中，进行模型测试和数值模拟以研究反面纵向裂缝对隧道衬砌力学性能的影响。研究结果表明：（1）反面已存在的裂缝加剧了断裂带后方的破碎破坏，导致隧道的脆性失稳。（2）开裂隧道的变形过程最初线性发展直至急剧增加。此外，在突然破坏之前，破裂衬砌损坏区域的变形幅度和增长幅度大于完整衬砌。（3）裂纹导致损坏区域的弯矩明显减小，而推力对裂纹的数量不那么敏感；（4）倒转中预先存在的裂缝削弱了衬砌抵抗围岩压力的能力，并增加了拱脚在接触压力中的份额；（5）转弯处预先存在的裂缝减小了衬砌的承载面积，从而削弱了弯曲刚度，有利于转弯处的破碎破坏，这是开裂隧道承载力下降的主要原因。（3）裂纹导致损坏区域的弯矩明显减小，而推力对裂纹的数量不那么敏感；（4）倒转中预先存在的裂缝削弱了衬砌抵抗围岩压力的能力，并增加了拱脚在接触压力中的份额；（5）转弯处预先存在的裂缝减小了衬砌的承载面积，从而削弱了弯曲刚度，有利于转弯处的破碎破坏，这是开裂隧道承载力下降的主要原因。（3）裂纹导致损坏区域的弯矩明显减小，而推力对裂纹的数量不那么敏感；（4）倒转中预先存在的裂缝削弱了衬砌抵抗围岩压力的能力，并增加了拱脚在接触压力中的份额；（5）转弯处预先存在的裂缝减小了衬砌的承载面积，从而削弱了弯曲刚度，有利于转弯处的破碎破坏，这是开裂隧道承载力下降的主要原因。