Comparative Analysis of Influence of Foundation on Reinforced Soil Retaining Walls

Two centrifuge model tests were carried out to study the influence of foundation on reinforced soil retaining wall. Firstly, the similarity scale was obtained using the similarity theory. Then, materials used in model tests were determined according to the scaling law and models with sand and clay foundations were designed. Finally, values of displacement, horizontal earth pressure on the wall, vertical earth pressure, and reinforcement strain during the construction stage and the loading stage were collected and analyzed. Results show that the maximum horizontal displacement was located at the top of the structure for the wall constructed on compacted sand foundation; the horizontal displacement of the model wall constructed on clay foundation at the end of the construction was about 3 times that constructed on sand foundation and its bottom displacement could increase to 30 cm in the loading stage; the horizontal earth pressure coefficient was nonlinear along the wall height and was smaller in the clay foundation case. Besides, the value in the loading stage was smaller than that in the construction stage in both cases. Compared with the wall constructed on sand soil foundation, the deformation of the clay could reduce the concentration of the vertical stress at the bottom of the wall facing, resulting in the ratio of the vertical stress to the self-weight stress being close to 1.0. As the displacement of the wall constructed on clay foundation increased, the strain was about 3 times that with compacted sand foundation, and the position of the maximum reinforcement strain was far away from the wall facing.