Micro-mechanical analysis of caisson foundation in sand using DEM : particle shape effect

Abstract

The caisson foundation has been extensively studied with experimental, analytical and numerical methods. However, the effect of particle shape on the caisson foundation is somehow ignored. In this paper, the caisson foundation is analyzed with DEM and the effect of particle shape is discussed in detail by introducing spherical and tetrahedral particles without rolling resistance, and spherical particle with rolling resistance. Firstly, a series of biaxial tests are simulated on samples with different particle shapes to obtain the soil properties, and typical shear behaviors are observed in all simulations. Then the effect of particle shape on the macro- and microscopic behaviors of caisson foundation is then investigated with different loading conditions. The results show that when subjected to external loading, compared with spherical particles, caisson foundation with angular particles or spherical particles with rolling resistance (1) has increased horizontal and rotational bearing capacities; (2) has much smaller particle rotation due to the strong interlocking capacity between particles; (3) exhibits higher stress concentration and magnitude of force chains; and (4) experiences significant increase on the magnitude of the anisotropy.