Liquefaction and Dynamic Properties of Assemblies with Particles of Spherical and Ellipsoidal Shapes: A Discrete Element Approach

Methodology Used For The Study

Soils are discontinuous in nature and hence it is appropriate to model the assembly of grains considering their discrete behaviour. The state of knowledge related to liquefaction and its associated phenomena has been studied in detail during the last few decades by analytical and laboratory experiments (Seed & Lee, 1966; Ishihara, Tatsuoka, & Yasuda, 1975, 1975; Vaid & Thomas, 1995). Generally the cyclic behaviour obtained from analytical methods is based on continuum approach. Since the continuum approach does not take into account the particulate nature of the soil mass, the deformation and failure modes may be affected. Hence it is important to consider the particulate nature of the soil assembly considered and hence discrete element method (DEM) is adopted in this study. DEM pioneered by Cundall (1971) was developed to study the rock slope which was later extended to the study of application in granular media. DEM is based on the principle that each particle is modeled as an element obeying Newton’s second law of motion. The movement of each particle is monitored by solving the equations of motion. The relative displacement at the contacts gives rise to a contact force which is evaluated by force-displacement law. DEM has been successfully used by several researchers (Ng & Dobry, 1994; Sitharam, 2003; Dinesh, Sitharam, & Vinod, 2004) to understand liquefaction.