Study on the Mechanical Characteristic of Micropiles Supporting Landslide Under Step-Loadings

To study the reinforcement effect and the mechanical characteristic of micropiles in supporting soil landslide under step-loadings, two soil landslide models were built: the reinforced landslide with three rows of micropiles and the unreinforced landslide. The mechanical characteristics and failure mode of micropiles under step-loadings were analyzed by monitoring the displacement of landslides and pile-tops, and the strain of micropiles. The results indicate that the bearing capacity of the reinforced landslide with micropiles is increased by three times compared to the unreinforced landslide. Micropile plays a major role in anti-bending and shear-resistance. The failure pattern of micropiles shows reverse “S”-type. The destruction area of the back pile and the middle pile mainly distributes in the area that 1.7–3.1 times pile diameter above the sliding surface and the area that 1.7–2.9 times pile diameter below the sliding surface. The destruction area of the front pile mainly distributes in the area that 2.6–4.3 times pile diameter above the sliding surface and 1.7–2.9 times pile diameter below the sliding surface, and destructiveness of the front pile is less than that of the other two rows of piles. Before the landslide enters the unstable status, the bending moments of different rows of piles have not much difference. However, when the landslide is at the completely failure state, the back pile and the middle pile play more important role than the front pile.