# Landslide-Tunnel Interactions and Control Countermeasures under an Orthogonal System
## 1 Introduction  
Tunnel-crossing landslides are often encountered during tunnel construction. Excavating tunnels can displace landslides, and landslides can cause damage to the tunnel's lining structures and lead to instability in the surrounding rock [1; 2]. Therefore, it is important to study the influence of interactions between tunnels and landslides and ways to control the stability of the surrounding rock. Tunnel excavation inevitably disturbs the original rock stress field, resulting in stress redistribution. The uneven stress distribution is more obvious when a tunnel passes through unstable areas such as landslides. Owing to the problem of tunnel alignment, many tunnels inevitably cross landslides during construction. Tunnel excavation can trigger or accelerate landslide movement, so landslides can have a great impact on tunnels [3; 4]. Currently, the main methods used to study tunnel and landslide interactions are numerical simulations, theoretical analyses, and laboratory tests. [PERSON] et al. (2022) established three physical model tests in the laboratory to study the influences of different anti-slide pile reinforcement effects on landslides and tunnels. The results showed that after taking the pile-anchor reinforcement measures, the deformation of the landslide, the bending moment of the tunnel, and the contact stress at the interface between the tunnel and the landslide mass are all significantly reduced, further improving the operational safety of the tunnel [5]. [PERSON] et al. (2022) focused on the parallel system of tunnel-landslide interactions and conducted model tests with three tunnel models of different burial depths. The test results indicate that the greater the burial depth of the tunnel, the smaller the impactof stress release after tunnel excavation on the slope surface above the tunnel. With the increase in burial depth, the strain of the tunnel gradually increases [6]. In order to study the influence of landslide and anti-slide piles on tunnel deformation, [PERSON] et al. (2022) established three physical model tests with different anti-slide pile spacings. The results show that with the increase in the anti-slide pile spacings, the deformation of tunnel lining and the pressure and bending moments acting on the tunnel also gradually increase. The stability of the surrounding rock can be effectively controlled by reducing the spacing of anti-slide piles [7]. [PERSON] et al. (2016) developed a mechanical theoretical model for tunnels crossing landslides by researching deformation characteristics and stress mechanisms under various tunnel failure modes. They also analyzed interactions between landslides and summarized the factors that influence tunnel deformation and stress distribution patterns [8]. [PERSON] et al. (2020) investigated variation trends in the shear strength parameters of weak structural planes during large deformations and landslide failure from an experimental perspective. Their model tests indicate that landslide failure can be divided into four distinct stages: the soil compaction stage, the crack generation stage, the crack propagation stage, and the sliding plane transfixion stage [9]. [PERSON] et al. (2020) and [PERSON] et al. (2021) used finite element simulation software to calculate and analyze the interaction mechanisms between tunnels and landslides under various factors and scenarios and validated the simulation results. They employed three-dimensional numerical analysis methods to study the relationship between the TBM tunnel excavation and landslides [10; 11]. With these methods, a better understanding of the interaction effects between tunnel and landslide systems can be achieved. Some scholars have studied tunnels and landslides separately, considering the deformations of each one independently without accounting for interaction effects between the two [12; 13]. However, many other researchers have studied the interaction effects between tunnels and landslides [14; 15].