Formulating a constitutive model for anisotropic sand using stress probing analysis

Abstract

Natural sands often possess anisotropic fabric that significantly influences their mechanical behaviour. This study examines the incremental stress–strain relationship of anisotropic sand through stress probing tests conducted via discrete element simulations. The tests apply incremental stress in various directions to identical soil samples, yielding corresponding strain increments. Numerical probing tests under various initial states were conducted to assess the effects of fabric anisotropy on the incremental response of sand. Based on the test results, explicit formulations for the yield surface, plastic flow direction, and plastic modulus were derived, facilitating the development of an anisotropic constitutive model within the framework of anisotropic critical state theory. The proposed model can accurately capture the behaviour of anisotropic sand under varying initial states and loading conditions.