Discrete and Continuum Numerical Modeling of Soil Arching between Piles

Abstract

The aim of this study was to investigate the soil-arching phenomenon between piles by adopting two different numerical methods: the discrete-element method and the finite-difference method. The discrete-element method, in which soil is represented by an assembly of particles of various shapes that interact with friction at contact points, allows analysis of the phenomenon at the microscopic level. The discrete-element method naturally captures the mechanical behavior of frictional materials. In contrast, the finite-difference method examines the problem at the macroscopic level. Specifically, soils are considered homogeneous materials from the macroscopic viewpoint. In the continuum approach, an appropriate constitutive model that considers the shear-resistance degradation is used to capture the evolution of frictional materials as obtained by using the discrete approach. The numerical microparameters and macroparameters for the two numerical models were calibrated from triaxial test simulations. A comparison of these two approaches for the case of a soft soil improved by vertical piles was conducted. The study highlights the limitations and advantages of each method with respect to the soil-arching investigation.