## 1 Introduction  
For rock masses containing structural surfaces, shear slip or misalignment often occurs along the structural surface, resulting in a reduction in the stability and integrity of the structural surface rock mass. Anchor support, as an important support method, can limit the interlayer misalignment or slip of rock containing a structural surface, thus improving the stability of the rock mass. However, the mechanism of the anchor bolt reinforcement of jointed rock mass is very complex, especially for a full-length bonded bolt. When the structural surface is dislocated, the bolt near the structural surface has significant local characteristics. It is this local characteristic of the anchor bolt that improves the shear strength of the structural surface. Therefore, domestic and foreign scholars have carried out a lot of research and exploration. Since [PERSON] [1] studied the shear strength of rock with anchored granite structural surfaces in 1974, many experts and scholars have carried out in-depth research on the shear failure law and anchoring mechanism of the structural surface, achieving fruitful results in theory and experimental simulations. [PERSON] [2] proposed an estimation formula for the effect of a bolt on the shear strength of a structural surface, and the view has been generally recognized. However, it is necessary to know the axial stress and the shear stress of the bolt to calculate the shear strength of the structural surface. For this reason, [PERSON] [3], [PERSON] [4], [PERSON] [5], [PERSON] [6], [PERSON] [7], [PERSON] [8], [PERSON] [9], [PERSON] [10] have studied the geometric dimensions, anchoring methods, and failure forms of bolts. In addition, [PERSON] [11] conducted tests on large-size specimens to analyze the effects of the bolt contact area and installation density on the shear strength of the structural surface; [PERSON] [12; 13] conducted direct shear tests under cyclic loading conditions, and [PERSON] [14; 15] and [PERSON] [16; 17] investigated the shear characteristics of rock at the anchored structural surface using the boundary conditions of constant normal stiffness. In terms of simulation, [PERSON] [18], [PERSON] [19], and [PERSON] [20] have used the FISH language to modify the mechanical behavior of the PILE structural element based on FLAC\({}^{\text{3D}}\) software to realize the simulation and application of bolt shear breakage in the anchorage structural surface. [PERSON] [21] used the PILE element, and the shear effects under different anchorage methods of structural surface rock were simulated. [PERSON] [22], [PERSON] [23], and [PERSON] [24] have used solid elements in FLAC\({}^{\text{3D}}\) software to simulate a bolt and have studied the stress characteristics of a bolt under the shear displacement of a structural surface. Furthermore, the stress state of the surrounding rock is different under different burial depths [25], so the selection of a suitable anchor support method is key to controlling the stability of the surrounding rock [26]. To address the issue of the local deformation range of an anchor bolt, one study [1] considered that the length range of the shear deformation section of an anchor bolt is about 3-4 times its diameter. Another study [11] considered that the length range of the shear deformation section of the anchor bolt is about 2-4 times its diameter. The authors of [27] considered that the length range of the shear deformation section of an anchor bolt is about 3-5 times its diameter. However, the extent of the local deformation of an anchor bolt increases with the increase in the shear displacement of the structural surface. Most of the previous studies on the shear strength of an anchored structural surface have been conducted from the perspective of the local deformation of an anchor bolt after the misalignment of the structural surface, and few studies have been conducted on the local deformation of an anchor bolt during the misalignment of the structural surface.