## 2 Overview of Contact Experiment  
### Specimen Design  
In order to investigate the connection performance of the novel type of corrugated pipe-restrained grout anchor joint, 17 specimens were designed for pull-out experiments. The cross-sectional dimensions of the design components are 200 \(\times\) 200 \(\times\) 700 mm, and the protective layer's thickness is 25 mm. The main body of each specimen is composed of C30 ordinary concrete, and the corrugated pipe is filled with Wei Lan JW-E1 A, B, and C grouting materials, respectively. The compressive strengths of these three grouting materials are equivalent to those of C40,  
Figure 1: Prefabricated shear wall with the new corrugated pipe grout anchor joint. (**a**) Perspective view; (**b**) schematic diagram. C50, and C60 ordinary concrete. The grouting materials produced by Zhengzhou Jingwei Building Materials Technology Co., Ltd. (Zhengzhou, China). Exhibit characteristics such as self-compacting and non-shrinking hardening, meeting the requirements of the experiment. A centrally located steel plate is embedded within each specimen to mitigate eccentricity to ensure that the clamping end steel bars and the grout anchor steel bars are aligned on the same straight line. The vertical steel bars in the main body of the specimen are 4C12, where 4 indicates the number of bars, C indicates that the steel bar is grade 3, 12 indicates the diameter of the bar, and the stirrups are C8@200, where C indicates that the steel bar is grade 3, 12 indicates the diameter of the bar, @200 indicates the spacing of the stirrups. The explanation below is the same. The metal corrugated pipe has a diameter of 40 mm and a height of 600 mm. The anchorage lengths of the grout anchor steel bars are adjusted according to the experimental design, ensuring alignment with the center of the corrugated pipe before injecting the grouting material. Based on the Chinese code GB 50010-2010 (the Code for Design of Concrete Structures), the basic anchorage length of the steel bar is calculated using the formula \(\mathrm{L_{ab}}=\alpha f_{y}/f_{t}\cdot d\), where the shape coeffic ient \(\alpha\) for ribbed steel bar is \(0.14,f_{y}\) is the tensile design strength of the steel bar, \(f_{t}\) is the design tensile strength of concrete, and \(d\) is the diameter of the steel bar. The anchorage length is determined by \(\mathrm{L_{a}}=k\cdot\mathrm{L_{ab}}\), with \(k\) is the anchorage length coefficient. For this experiment, values of 0.4, 0.6, 0.8, 1.0, and 1.2 were selected for k. In order to assess the impact of U-shaped stirrups on the joint performance of grout anchor structures, 15 specimens were designed without U-shaped stirrups, while the remaining two included U-shaped stirrups for comparative analysis. Figure 2 illustrates the construction and dimensions of the specimen. The clamping and grout anchor steel bars are aligned on the same straight line. Displacement gauges W1 and W2 are positioned adjacent to the clamping steel bar, while W3 and W4 are symmetrically arranged on the concrete surface near the grout anchor steel bar. Gauge W5 is placed on the welded steel bar at the interface between the grout anchor steel bar and the concrete. The structural schematic diagram of the center positioning steel plate is shown in Figure 3. The center-positioning steel plate has a thickness of 2 mm, and the steel bars are symmetrically placed on both sides at a spacing of 100 mm. HRB400 C14 steel is employed for the grout anchor steel bars, clamping steel bars, positioning steel plates, and distributed steel bars. The specific parameters of the specimens in Group A are listed in Table 1. The specimen numbering format in the table employs an \"A-B\" scheme, where \"A\" denotes the concrete strength grade corresponding to the grouting material, and \"B\" signifies the influence coefficient of the basic anchorage length of the grout anchor steel bar.