Application of a New Steel Pipe and Anchor Combination System in Tunnel Landslide Reinforcement

China has a vast territory and complex geological conditions. In the process of tunnel construction, the formation of landslide at the entrance of a tunnel is often the result of comprehensive action of many factors. It is necessary to carry out research on new technology and new process according to local conditions while making full use of the existing mature technology for prevention and control. Based on the landslide treatment project of Gaowuji tunnel in Pengan, Sichuan Province, a composite reinforcement system of conventional steel pipe with fully bonded anchor is introduced: by using the wall protection capacity of large-diameter steel pipe, effectively control the hole collapse during the follow-up drilling without casing, and reduce the construction difficulty of super long anchor; the steel pipe, as a load-bearing component, participates in the work together to improve the defect of insufficient strength of single anchor bar; the soil properties of the sliding zone are improved and the deformation of the sliding body is further restrained by the split seepage grouting in the pipe. After reinforcement, the whole slope is stable and the deformation of slope body is controllable, which can provide technical reference for similar projects.