On mechanical behaviour of clastic soils: numerical simulations and constitutive modelling

Clastic soil is ubiquitous in practice but still poses a challenge for testing and modelling. Conventional laboratory tests with small sizes are not suitable for the large grain size, while large-scale tests and field tests are often too costly and time-consuming. In this paper, the mechanical behaviour of clastic soil is described by a hypoplastic constitutive model based on numerical simulations considering both the soil matrix and breccia. The numerical simulations indicate that the breccia content, gradation and the overconsolidation ratio have a significant influence on the strength, deformation and failure pattern of the clastic soil. The coarse particles are found to change the stress path developed in the soil matrix and consequently influence the critical state of the soil matrix. Moreover, the coarse particle distribution based on computed tomography scanning seems to have a larger impact than the breccia content on the failure pattern of clastic soils.