## 2 Experimental Outline
### Analysis of Contact Force between Surrounding Rock and lining Structure  
Eight measurement points were placed on the surrounding rock and lining contact surface to track the surrounding rock-lining contact force. The contact force between the surrounding rock and lining structure is pressure, and it varies, as Figure 9 illustrates. This change's trend is comparable to the surrounding rock's radial stress in the horizontal direction at the arch waist in Section 3.1. As time goes on, the surrounding rock-lining contact force primarily goes through the deformation stage and the stabilization stage. It also demonstrates how the surrounding rock's creep effect causes the rock-lining contact force to change over time, exhibiting a time-dependent characteristic. The lining structures were subjected to the pressure of the surrounding rock in the following order: left and right arch waist > left and right spandrel > left and right arch foot > arch crown > arch bottom. However, when the pressure increment was calculated as a percentage of the instantaneous pressure at the time of loading, the right arch waist had the smallest incremental proportion and the left and right arch top the largest. Figure 8: Radial displacement of lining structure (Ac for arch crown, Ab for arch bottom, Aw\({}_{1}\) for left arch waist, Aw\({}_{r}\) for right arch waist, S\({}_{l}\) for left spandrel, Af\({}_{l}\) for left arch foot). Figure 9: Contact force between surrounding rock and lining structure. Analysis of Factors Influencing the Time-Dependent Characteristics of Stress and Deformation in Surrounding Rock and Lining Structure  
Influence of Burial Depth on Time-Dependent Characteristics of Stress and Deformation in Surrounding Rock and Lining Structure  
The stress and deformation of the surrounding rock and lining are significantly influenced by the burial depth (\(\mathrm{d_{b}}\)), and the time-dependent characteristics of the stress and deformation of the surrounding rock and lining may differ depending on the burial depth. At burial depths of 15, 30, and 45 m, the time-dependent characteristics of stress and deformation in the surrounding rock and lining structure are examined when the lateral pressure coefficient is 0.3. The surrounding rock stress, the internal force and displacement of the lining structure, and the surrounding rock-lining contact force are all monitored during the model test. Figures 10 and 11 illustrate how the surrounding rock stress varies under different burial depth conditions. The surrounding rock stress fluctuates sharply in response to changes in burial depth before gradually stabilizing over time. The surrounding rock stress increases as tunnel depth increases, and the time-dependent characteristics of these changes become more evident. As an illustration, consider the monitoring point A1 in Figure 10. The load retention process caused the radial pressure to increase by 0.41 kPa at a tunnel depth of 15 m, and at a tunnel depth of 45 m, it increased by 2.07 kPa. The time-dependent characteristics of stress and deformation in surrounding rock and lining are significantly influenced by the tunnel burial depth. The three types of burial depth conditions of surrounding rock stress, as well as the 3.1 section of surrounding rock stress, are consistent in terms of size and distribution. As the radial distance grows, the surrounding rock stress increases vertically, climbs, and then falls horizontally, and on both sides, the stress size and distribution change symmetrically in both vertical and horizontal directions. Figure 12 illustrates how the surrounding rock-lining contact force varies under various burial depth circumstances. Similar to the surrounding rock-lining contact force in Section 3.3, the surrounding rock pressure on each portion of the lining under varying burial depths follows the same order, which is likewise left and right arch waist > left and right spandrel > left and right arch foot > arch top > arch bottom.