## 1 Introduction  
Cable-supported bridges are classified into cable-stayed and suspension bridges. Suspension bridges are one of the main types of long-span bridges [1, 2] and possess significant benefits in terms of material properties and height-span ratio of the stiffening girders [3]. Suspension bridges are comprised of main beams, tower piers, cables, and anchorages, with the anchorages playing the major role in anchoring the suspension bridge's main cables [4]. Based on the main cable anchoring method, suspension bridges are classified into self-anchored or earth-anchored. In a self-anchored bridge type, the main cable is directly attached to the stiffening girder, whereas in the earth-anchored type, the main cable is directly attached to the bridge via anchorages at the beginning and end locations. Anchorages are vital parts of earth-anchored suspension bridges, and support the tension of the main cables [4, 5].  
Anchorages for earth-anchored suspension bridges can be classified into gravity and tunnel types (Figure 1). The gravity type has a simple bearing mechanism by considering the weight of the concrete body as a factor of support. However, the gravity type has the disadvantage of requiring a huge amount of concrete and excavation. The tunnel type involves a method wherein the cable load is supported by excavating a tunnel in a relatively good rock mass. Subsequently, the tension member and concrete are filled in the excavated spot, making use of the frictional and cohesion resistance produced by the self-weight of the body and the front soil layer. The tunnel type design offers advantages because it is economical and minimizes environmental degradation of the surrounding environment compared to the gravity type [6].  
The majority of the research conducted on suspension bridges is currently focused on bridge design technology [7, 8], the dynamic response of structures under load [9, 10], and bridge monitoring and structural reliability evaluation [11, 12]. In contrast, there have only been a few studies analyzing suspension bridge anchorages [13].  
Tunnel-type anchorages are rarely used in design, and their behavior when subjected to a pull-out load has still not been determined. Tunnel-type anchorages have mechanical characteristics similar to uplift piles and rock anchors [3]. Several model experiments and numerical simulations have been performed to investigate the mechanical behavior of uplift piles [14, 15, 16, 17, 18, 19, 20, 21, 22, 23]. However, because the structures differ in shape, size, and material, it is difficult to relate the failure mode of the uplift pile to the failure mode of anchoring. [PERSON] et al. [24] analyzed the failure mode from the initial stage to the failure stage of the tunnel-type anchorage through a two-dimensional small-scaled model test and image processing, and confirmed that the failure mode of the tunnel-type anchorage exhibited a wedge-shape. Additionally, the presence of discontinuities, such as joints and artificial and naturally occurring faults, influence the failure mode of tunnel-type anchorages [3]. However, there has been little study examining tunnel-type anchorages in relation to rock joint properties and geometry.  
The purpose of this study was to evaluate the pull-out behavior of tunnel-type anchorages based on geometric and rock joint characteristics. A series of finite element (FE) analyses of tunnel-type anchorages were carried out. The enlarged part, anchorage spacing, joint orientation, joint spacing, and the shear strength of the rock joints were investigated and considered as the factors influencing pull-out behavior.