Cyclic mechanical behaviour of granular soils: experimental results and constitutive modelling

The paper presents cyclic torsional shear test results obtained on dense Toyoura sand specimens. The dependency of the mechanical response on loading amplitude is discussed. Equivalent/tangent elastic shear stiffness and damping ratio are taken into consideration. Their evolution with the number of cycles performed at different loading amplitudes is analysed: the irreversibility of the material mechanical response is discussed. Experimental data are then reproduced by means of a non associated multiple mechanism elasto-viscoplastic constitutive model characterised by two generalized plastic mechanisms: one viscoplastic and one inner kinematic plastic which is capable of capturing the material mechanical response even when small cyclic tests are performed.