# Model Test of Stress and Displacement of Recyclable Anchor Rod Support Structure
## 1 Introduction  
The rapid development of the social economy and science and technology contributes to the gradual expansion of urban space, and the development of underground space has become the main development trend at present. The deep foundation pit develops in a deeper and larger direction, inducing higher requirements for the safety and applicability of deep foundation pit support [1; 2; 3]. Among them, the pile and anchor support is particularly suitable for complex construction environments, can shorten the construction period, and is widely applied in foundation pits. [PERSON] et al. [4] adopted the pile-anchor rod support in a complex environment, realized the support, and obtained the internal force distribution law of the supporting structure. [PERSON] et al. [5] effectively controlled the overall deformation of surrounding buildings and supporting structures using the pile and anchor rod support in the construction environment of adjacent buildings. [PERSON] et al. [6] analyzed the pile-anchor rod support structure and obtained the change rule of the surface settlement around the foundation pit with excavation. An anchor bolt, as a temporary supporting structure for underground engineering construction, is left underground after it plays its role. Since it is considered concealed engineering, its length is difficult to trace after the completion of construction, and sometimes it will exceed the red line, affecting future underground construction and causinga waste of resources that cannot be recovered. As a result, the subsequent underground engineering construction is impeded [7; 8; 9; 10]. Driven by the sustainable development strategy of \"green building materials, green buildings\", recoverable bolt technology will become the mainstream development trend. Many researchers have proposed the concept of new recyclable support and applied it in practical engineering projects [11; 12; 13; 14]. [PERSON] et al. [15] elaborated on the commonly used recycling mechanism of recyclable anchor rods based on the application status of recyclable anchor rod technology and provided suggestions on its research and development direction. [PERSON] et al. [16] conducted a pull-out test on the new recyclable anchor rod and revealed the distribution law of the surrounding soil's tensile stress in the pulling-out process of the recyclable anchor rod. [PERSON] et al. [17] investigated the bearing deformation characteristics of the recyclable anchor rod, suggesting that the bearing characteristics of the recyclable anchor rod were better when the horizontal dip angle of the recyclable anchor rod was between 15\({}^{\circ}\) and 35\({}^{\circ}\). [PERSON] et al. [18] performed model tests of the pile-anchor rod support and prefabricated support under the same conditions, concluding that a prefabricated support structure could better limit displacement. [PERSON] et al. [19] discussed the working mechanism of recyclable anchor rods and verified that recyclable anchor rods had a good bearing performance. [PERSON] et al. [20] applied recyclable anchor rod anchor rods in deep foundation pit engineering. The engineering example demonstrated that the recyclable anchor rod did not affect the surrounding site on the premise of ensuring safe recovery. To sum up, the use of recyclable anchor rods can assure good bearing characteristics and be recycled to curtail resource waste. At present, the analysis of the stress and deformation characteristics of pile-anchor rod support structures focuses on numerical simulation [21; 22; 23]; however, it is worth noting that field testing for this research entails a lengthy cycle and high costs. While the research on pile-anchor-supporting structures mainly focuses on common anchors, little attention has been given to recoverable anchors and the subsequent displacement changes in the foundation pit upon anchor recovery. Evaluating the displacement changes in the supporting structure after bolt recovery remains a crucial indicator for measuring the stability of the foundation pit.