# Research on the Self-Drilling Anchor Pull-Out Test Model and the Stability of an Anchored Slope
## 1 Introduction  
Slope stability is a key issue in geotechnical engineering. In complex geological conditions or loose and fractured rock masses, traditional support technologies have been widely applied. However, in certain challenging conditions, such as fill soils and soft soils, issues such as borehole collapse, necking, insufficient anchor length, and poor grouting quality may occur [1, 2]. These problems increase construction difficulty and may even compromise the safety of support structures and slope stability. To address these challenges, self-drilling anchor bolts have been increasingly adopted [3, 4, 5, 6]. As an advanced anchoring technique, self-drilling anchor bolts are well-suited for complex geological conditions and challenging construction environments. They integrate drilling, grouting, and anchoring into a single process, offering simple construction and high efficiency. Due to these advantages, they are widely used in slope reinforcement, unstable rock mass stabilization, deep excavation support, and tunnel support [7].  
Currently, there are numerous practical applications of hollow self-drilling anchor bolts in engineering. [PERSON] et al. verified, through the engineering practice at the Xigu Hydropower Station fault fracture zone slope, that the hollow self-drilling anchor bolts,with their simultaneous grouting characteristic through the hollow shaft, significantly improved the anchoring capacity of the surrounding rock and addressed the technical bottleneck of difficult hole formation. [PERSON], based on case studies of hydropower projects, systematically analyzed the hole-formation efficiency and grouting effectiveness of hollow self-drilling anchor bolts in loose rock-soil formations, pointing out that their \"drilling-grouting-anchoring\" integrated process could significantly enhance the overall integrity of support structures. Similarly, [PERSON], in an engineering project at a deep foundation pit in the mountainous area of Southern Anhui, verified that the construction process of self-drilling anchor bolts reduced the difficulty of hole formation, especially demonstrating greater advantages in gravelly soil layers. These achievements highlight that hollow self-drilling anchor bolts, when used to replace traditional soil nails, anchor cables (or bolts) for slope protection in complex geological conditions and can effectively resolve problems such as difficult hole formation, hole collapse, and slow drilling in such strata [8]. Furthermore, due to the elimination of casing for wall protection during construction, the use of hollow self-drilling anchor bolts greatly improves construction efficiency, shortening the project timeline while reducing overall construction costs [9,10]. However, research on the application of hollow self-drilling anchor technology for reinforcing steep loose rock slopes is relatively scarce. Widely used case studies are mostly concentrated in tunnel and foundation pit projects, and there is insufficient accumulation of case analyses in loose fractured slopes. Therefore, this paper primarily focuses on the anchoring performance of self-drilling anchor bolts, conducting numerical simulation analysis of anchorage through experimental and numerical methods. Additionally, the Pile element model is refined to make its simulation results closer to reality, and actual engineering examples are used to validate the supporting performance of self-drilling anchor bolts, providing theoretical guidance and technical support for similar engineering projects.