Abstract: The decompression effect of expanded polystyrene (EPS) buffer layer in cantilever retaining wall was examined when the expansive soil expands due to rainfall infiltration. The expansion characteristics of Nanyang expansive soil were tested to determine its expansion coefficient under lateral and vertical loads. On this basis, the expansive soil-EPS buffer layer-cantilever retaining wall system was numerically simulated using ABAQUS to explore the influences of EPS buffer layer (thickness, elastic modulus, and interface friction) on the stress and deformation of the system. Numerical results indicate that EPS buffer layer effectively reduces the lateral pressure on the cantilever retaining wall and changes the distribution of soil pressure on the wall back. The EPS buffer layer with larger thickness and lower elastic modulus has better effect. The friction between EPS buffer layer, wall and expansive soil affects the distribution of lateral pressure on the wall, but does not affect the resultant force of the lateral pressure. In addition, the compression stiffness of EPS buffer layer is inversely proportional to its load reduction performance.

Key words: expansive soil, Expanded Polystyrene (EPS), flexible cantilever retaining wall, numerical simulation, earth pressure