# Model Test of Micro-Pile Group Reinforcing High Steep Landslide
## 4 Conclusions  
A large-scale model test was performed in order to simulate the effect of micro steel pile groups on high steep landslides. The force and deformation characteristics of micro steel pile groups set at the top of high steep landslide were investigated. The main conclusions can be drawn as follows:  
1. When the high steep landslide was generated, the deformation of the micro steel piles in different rows were consistent, showing good performance of the model test. The earth pressure was largely varied according to the relative position to the slip surface, due to the fact that the portion of the pile above the slip surface acted as an anchor.
2. The landslide thrusts on micro steel piles showed a triangular distribution concentrated in the lower half of the loaded section. The distribution of the slip resistance behind the pile was generally an inverted triangle, which was mainly located in the upper half of the loaded section. The main sliding resistance was observed in the local area behind the pile, below the slip surface.
3. There was a difference in horizontal displacement of the top of the piles in the micro steel pile group, due to the group's gradually increasing resistance. The horizontal displacement at the top of the first row of piles on the sliding side was the largest, and the horizontal displacement of each row of piles along the sliding direction decreased in turn.
4. The bending moment of the micro steel pile in the loaded section was mostly negative. The larger bending moment values were mainly in the range of eight times the pile diameter above the slip surface, with a maximum value of two times the pile diameter on the slip surface. The bending moment of the micro steel pile in the embedded section was mostly positive, indicating that the micro-pile was in a state of tension. The tension portion was concentrated in the area of six times the pile diameter under the slip surface, with a maximum value of four times the pile diameter under the slip surface.
5. The failure mode of the micro steel pile was mainly due to the bending damage occurring near the slip surface, and the failure mode of each row of piles was essentially the same. Hence, the reinforcement of the pile near the shear surface, in the vicinity of eight times the micro steel pile diameter around the slide surface, is recommended in order to increase the resistance of pile groups in the real-life project.  
Conceptualization, J.Y. and X.L. (Xueling Liu); methodology, J.Y.; model test, X.L. ([PERSON]); formal analysis, Z.Z.; data curation, K.J.; writing--original draft preparation, J.Y.; writing--review and editing, [PERSON] ([PERSON]); visualization, K.J.; supervision, Z.Z.; project administration, X.L. ([PERSON]). All authors have read and agreed to the published version of the manuscript.  
The authors would like to give sincere thanks to the funding agencies that supported this research. This work was supported by the Independent subject of Key Laboratory of Geohazard Prevention of Hilly Mountains, Ministry of Land and Resources of China (Grant nos. KLGHZ202102), China Geological Survey Project (Grant nos. DD20211314).  
Not applicable.  
The authors declare no conflict of interest.