Application of a combined arching model in the load transfer platform of rigid inclusion system with raft through FEM evaluation

Abstract

This study introduces a novel combined arching model for the load transfer platform (LTP) layer beneath a rigid raft within a rigid inclusion (RI) system. RI systems with different pile configurations and different LTP layer thicknesses (HLTP) were simulated via a 3-dimensional finite element method. Within the central unit cell of each case, vertical stress, horizontal stress, and lateral earth pressure coefficients were compared. The inflection points of horizontal stress were determined as the upper boundary of soil arch. Additionally, nonuniform stress distribution on the LTP layer is analyzed, revealing concentration above inclusion heads. The study identifies the relative spacing (HLTP / (S – D), where S = inclusion spacing and D = inclusion diameter) as a significant parameter capturing stress variation. This study concludes by proposing a “combined arching” approach for soil arching under a rigid raft, which considers a multi-arch mechanism for uniformly distributed stress and vertical slip surface for concentrated stress.