Stress relaxation coefficient and formulation for soft soils

Zhen-Yu Yin (1) , Q. Zhu (2) , J. Yin (3) , Q. Ni (4)

1 MEO - Matériaux Environnement Ouvrages
2 Shanghai Jiao Tong University [Shanghai]
3 POLYU - The Hong Kong Polytechnic University [Hong Kong]
4 University of Warwick [Coventry]

Current studies rarely investigate the stress relaxation behaviour of soft soils. This paper proposes a practically useful coefficient with a formulation based on the behaviour of stress relaxation under one-dimensional conditions. Firstly, the stress relaxation coefficient is proposed after summarising stress relaxation test results according to the linear relationship between the vertical stress and time in a double logarithmic plot. Secondly, from the newly developed rate-dependency based elasto-viscoplastic formulations, an analytical solution for stress relaxation is derived. A unique relationship connecting the stress relaxation coefficient, the secondary compression coefficient and the rate-dependency coefficient is then obtained. The applicability of the stress relaxation formulation with its key coefficient to determine time-dependent parameters is finally validated with published experimental results on reconstituted illite and Berthierville clay.

Mots clés: clays; laboratory tests; time dependence

Domaines: Mécanique [physics.med-ph]; Matériaux

Zhen-Yu Yin, Q. Zhu, J. Yin, Q. Ni. Stress relaxation coefficient and formulation for soft soils. Géotechnique Letters, 2014, 4 (1), pp.45-51. ⟨10.1680/geolett.13.00070⟩. ⟨hal-01007329⟩