Modeling crushable soils incorporating density effects via coordination number

Abstract

A rational constitutive model of crushable soils is proposed based on a novel evolution law for the grading index, which incorporates the effect of packing density on the particle crushing phenomena through the coordination number as an intermediate variable. The evolution law of the grading index reasonably combines the increase in the coordination number due to an increase in packing density; and the increase in the crushing resistance due to the increase in the coordination number. The effect of particle crushing on the stress–strain response is incorporated by lowering the critical state specific volume with the changing grading due to crushing. The validity of the proposed constitutive model was verified with an extensive series of elementary tests and DEM. The proposed model properly predicted two seemingly contradictory experimental evidence for crushable soils that: densely packed soil exhibits lesser crushing than loosely packed one under the same effective stress paths; densely packed soil is more likely to crush than loosely packed one when it is sheared. This approach can predict the stress–strain response of crushable soils under different packing densities and stress paths, offering valuable insights for comprehending the crushing responses.