1. Thermodynamic-based cross-scale model for structural soil with emphasis on bond dissolution
- Author
-
Zhang, Wei, Zou, Jia-Qiang, Bian, Kang, and Wu, Yang
- Subjects
Thermodynamics -- Models ,Strength of materials -- Analysis ,Soil structure -- Models ,Earth sciences - Abstract
The immersion weakening effect of natural soil has always been a difficult problem encountered in geotechnical engineering practice. The bond dissolution is a common cause of soil strength deterioration, which is not yet fully understood. In this study, a thermodynamic-based constitutive model of structural soils based on the [alpha] model is first established, considering the bond strength by modifying the yield surface size and gradually reducing the bond strength with the development of plastic strain. Furthermore, by taking the meso-mechanisms of bond dissolution into account, the evolution rule of the free energy during the bond dissolution process is derived based on a homogenization approach, and a thermodynamic-based constitutive model of structural soil with bond dissolution is thereafter developed. By comparing with the results of one-dimensional compression tests and conventional triaxial tests, the model is verified to be capable of reflecting the gradual destructuration process of soil while loading. The comparison with triaxial test results of completely decomposed granite after different immersion durations and parametric studies show that based on the cross-scale energy equivalence, the model can well reflect the strength deterioration characteristics of completely decomposed granite with bond dissolution mechanisms at the mesoscale fully considered. Key words: immersion weakening, bond dissolution, structural soil, thermodynamics, constitutive model. L'effet d'affaiblissement par immersion du sol naturel a toujours ete un probleme difficile rencontre dans la pratique de l'ingenierie geotechnique. La dissolution des liaisons est une cause frequente de la deterioration de la resistance des sols, qui reste encore mal comprise. Dans cette etude, un modele constitutif thermodynamique des sols structurels base sur le modele a est d'abord etabli, en considerant la force de liaison en modifiant la taille de la surface d'elasticite et en reduisant progressivement la force de liaison avec le developpement de la deformation plastique. En outre, en tenant compte des meso-mecanismes de dissolution des liaisons, la regle d'evolution de l'energie libre pendant le processus de dissolution des liaisons est derivee sur la base d'une approche d'homogeneisation, et un modele constitutif du sol structurel avec dissolution des liaisons, base sur la thermodynamique, est ensuite developpe. En comparant avec les resultats des essais de compression unidimensionnelle et des essais triaxiaux conventionnels, on verifie que le modele est capable de refleter le processus de destructuration progressive des sols en charge. La comparaison avec les resultats d'essais triaxiaux du granit completement decompose apres differentes durees d'immersion et les etudes parametriques montrent que, sur la base de l'equivalence energetique a l'echelle croisee, le modele peut bien refleter les caracteristiques de deterioration de la resistance du granit completement decompose avec des mecanismes de dissolution des liaisons a la meso-echelle entierement pris en compte. [Traduit par la Redaction] Mots-cles: affaiblissement par immersion, dissolution des liaisons, sol structurel, thermodynamique, modele constitutif., 1. Introduction The physical and chemical changes of soil after immersion in water are important factors affecting the mechanical properties of soil. The immersion weakening effect of some particular kinds [...]
- Published
- 2022
- Full Text
- View/download PDF