Method for calculating lateral earth pressure on rigid anti-slip piles with EPS inclusions

Expanded polystyrene (EPS) inclusions are placed between rigid anti-slip pile-free sections and slopes, causing soil displacement and transforming the lateral earth pressure from a static to an active state. This study proposes a calculation method for estimating the lateral pressure on rigid anti-slip piles with EPS inclusions based on the deformation coordination of the rigid pile–EPS geofoam–soil composite system and soil-arching effect behind the pile using the polar coordinate translation and oblique differential-unit methods. A Flac 3D numerical model, designed to verify the theoretical results and analyse the effect of load reduction due to EPS inclusions, confirmed the validity of the proposed calculation method. The load-reduction effects of EPS inclusions were positively and negatively correlated with the thickness and elastic modulus of the EPS specimen, respectively. Finally, three EPS-inclusion design methods are proposed: specimens manufactured by the first two methods facilitate both the load-reduction effect and poor economic efficiency, whereas those manufactured by the third method show excellent load reduction with economic efficiency. The results of this study contribute significantly towards research on EPS inclusions that could facilitate high-performance engineering and construction applications.