Model Test Study of High Embankment in High Soil Slope Reinforced by Chair-shaped Pile Retaining Wall

Due to the undulating terrain of mountainous area in western China, the high embankment works in high soil slope area need to be reinforced with a new type of retaining structure named chair-shaped pile retaining wall. In order to study the characteristics of stress and deformation of chair-shaped pile retaining wall at the high-filled subgrade in high soil slope, a scale model test was performed. The model of chair-shaped pile retaining wall and soil was made according to the similarity principle. The landslide thrust was simulated by the graded loading to measure and analyze structural displacement, structural internal force and earth pressure respectively. The results show that the horizontal displacement of chair-shaped pile retaining wall increases with the increase of the loading thrust. When the loading thrust is more than 40 kPa, the converted horizontal displacement value exceeds specification limit. The bending moment of the main pile is distributed in the shape of M that rotates 90 degrees in clockwise along the pile depth. The bending moment of the auxiliary pile is distributed in the shape of triangle above the interface between rock and soil, and in the shape of inverted trapezoid below the interface between rock and soil. The earth pressure of retaining plank decreases slightly at first before increasing along the depth direction. When the loading thrust is more than 40 kPa, a significant soil arching effect occurs between the retaining plank and the main pile. Since the earth pressure and bending moment of the main pile are greater than the value of the auxiliary pile, the main pile of chair-shaped pile retaining wall becomes the main bearing structure. This test can provide some reference for the application of chair-shaped pile retaining wall in high embankment in high soil slope. © 2021, Department of Journal of the China Railway Society. All right reserved.