## 1 Introduction
analyzed the load-bearing performance of tunnel anchors in soft rock with weak interlayers, and divided the deformation stages of the surrounding rock, and determined that the final failure mode of tunnel anchors under special geological conditions was similar to that of inverted wedges [3; 20]. At the same time, relevant scholars analyzed and determined the bearing capacity of tunnel anchors under different rock mass conditions based on the field model test monitoring data, which provided references for the actual construction of suspension bridges. [PERSON] et al. conducted a design load test, an overload test, a failure test, and a rheological test on the field scale model of 1:12, and the results showed that when the test load exceeded the overload stability coefficient, there would be an obvious inflection point; when the test load was less than the overload stability coefficient, the anchorage deformation and rheological characteristics were not obvious [21]. Based on the characteristics of rock mass at the test site and the performance of the test instrument, the relevant scholars improved the in situ scaling model test. Since the field scale model test is easily affected by the field loading conditions, and it is generally difficult to reach the surrounding rock failure conditions, it is difficult to fully grasp the failure form and uplift process of the surrounding rock in the anchoring area and determine the ultimate bearing capacity of the tunnel anchor [22]. Therefore, by simulating the failure conditions of surrounding rock through a similar indoor model test, it can further deepen the failure form of surrounding rock and the working mechanism of the \"tunnel anchor-surrounding rock\" co-bearing system. At present, relevant scholars have studied the relevant mechanism and optimal design of tunnel anchors and surrounding rock based on the tunnel anchor indoor model test. Some scholars have conducted relevant studies on the stress and deformation of the tunnel anchor body and surrounding rock, the stress mechanism and bearing capacity of anchor structure, and the deformation mechanism of surrounding rock by changing the variables such as anchor depth and surrounding rock conditions in laboratory model tests [23]. The collaborative analysis of numerical simulation results and tunnel anchor indoor model test data also provide a theoretical basis and reference for the analysis of failure deformation modes and bearing characteristics of tunnel anchors and the surrounding rock. [PERSON] et al. (2021) and [PERSON] et al. (2021) conducted tunnel anchor pullout tests based on indoor model tests [24; 25; 26; 27]. Based on the test data and tunnel anchor failure phenomenon, the bearing capacity and failure mode of tunnel anchors were further analyzed on the basis of clarifying the influencing factors of tunnel anchor failure. The above field and laboratory model experiments have played a key guiding role in the subsequent analysis of tunnel anchor-bearing capacity and tunnel anchor system stability, but both of them will be affected by in situ test site conditions, similar test materials, and safety assurance. Therefore, the relevant test results are insufficient to fully understand the load-bearing characteristics of tunnel anchors under different engineering geological conditions and the failure modes affected by the mechanics and structural characteristics of surrounding rock mass. Therefore, it is very important to study the load-bearing mechanism of tunnel anchors and the deformation of surrounding rock mass. The main disadvantage of tunnel anchorage is that the geological conditions of the surrounding rock in the anchoring area are relatively high, which involves the interaction between the anchorage and the surrounding rock and the deformation of rock mass under load, and its bearing mechanism is relatively complex. Wujiagang Yangtze River Bridge is the first tunnel anchorage with conglomerate strata in China.