Voids behind linings are a typical problem in the majority of operational tunnels. Previous researches had pointed out a high correlation between the voids and tunnel damages. However, mainly single tunnels have been investigated so far. In fact, few studies focused on the cracking performance of asymmetric double-arch tunnels originating from the relative radial displacements around the void. Herein, by combining numerical simulation and model test, the real three-dimensional response of the asymmetric double-arch tunnel structures caused by the voids is reproduced. Results reveal that crack patterns around the void can be classified into three main types. Transverse cracks are clearly the typical cracks and the spatial distributions are closely associated with void dimensions. Moreover, the localized voids imply uneven earth pressure distribution near the void, producing an asymmetric radial relative displacement and local bidirectional internal forces. It is found that the axial force is much higher in the circumferential direction in comparison with the longitudinal force. Consequently, the longitudinal bending moment plays a decisive role in the cracking performance, and the tensile stress in longitudinal direction becomes higher, changing the usual mechanism of cracking of the linings. For the tunnel opposite to the voids, a slight growth of the earth pressure is observed at the connection between the vault and the middle wall, accelerating the overall cracking of the linings.

衬砌后面的空隙是大多数运营隧道中的典型问题。先前的研究指出了孔隙与隧道破坏之间的高度相关性。但是，到目前为止，主要研究了单条隧道。实际上，很少有研究关注非对称双拱形隧道的开裂性能，该隧道是由于空隙周围的相对径向位移引起的。在此，通过数值模拟和模型测试相结合，再现了由空隙引起的非对称双拱形隧道结构的真实三维响应。结果表明，空隙周围的裂纹类型可分为三种主要类型。横向裂纹显然是典型的裂纹，空间分布与空隙尺寸密切相关。此外，局部空隙意味着靠近空隙的土压力分布不均匀，从而产生不对称的径向相对位移和局部双向内力。可以发现，与纵向力相比，轴向力在圆周方向上要高得多。因此，纵向弯矩在开裂性能中起着决定性的作用，并且在纵向方向上的拉应力变高，从而改变了衬里开裂的通常机理。对于与空洞相对的隧道，在拱顶和中壁之间的连接处观察到土压力略有增长，从而加速了衬砌的整体开裂。已经发现，与纵向力相比，轴向力在圆周方向上要高得多。因此，纵向弯矩在开裂性能中起着决定性的作用，并且在纵向方向上的拉应力变高，从而改变了衬里开裂的通常机理。对于与空洞相对的隧道，在拱顶和中壁之间的连接处观察到土压力略有增长，从而加速了衬砌的整体开裂。已经发现，与纵向力相比，轴向力在圆周方向上要高得多。因此，纵向弯矩在开裂性能中起着决定性的作用，并且在纵向方向上的拉应力变高，从而改变了衬里开裂的通常机理。对于与空洞相对的隧道，在拱顶和中壁之间的连接处观察到土压力略有增长，从而加速了衬砌的整体开裂。