Study on Soil Arching in the Cushion of Composite Foundation

Abstract

Laboratory experiments of rigid pile composite foundation were carried out in a tempered glass box. Particle image velocimetry (PIV) was used to investigate the global deformation fields. To explore the soil arching morphological and failure mechanism, the deformation patterns of the soil arching such as the arch thickness and arch rise were measured. Particle flow code (PFC) is used to study the effects of factors including the pile spacing, pile diameter, cushion thickness and soil particle size distribution on the arch thickness, arch rise and failure mode of the soil arching from the viewpoint of micro-scale. Results of the experimental tests and numerical simulation revealed the formation and failure mechanism of the soil arching effect at the level of particle size. It is shown that the pile spacing, pile diameter and cushion thickness play important roles in soil arching effects. The soil arching is easier to from with smaller pile spacing, larger pile diameter, lower porosity, wider soil particle distribution, or worse interface condition. The soil arching may fail or reform due to the rearrangement of soil particle.