A novel approach is proposed for the modeling of rigid-wheel and soft-soil interaction to efficiently compute normal and shear stress distributions in the contact area. The authors propose a velocity field in the vicinity of the contact area based on the physical nature of the problem. Thereupon, the incremental changes to the stress field are computed by resorting to elastoplasticity theory an...

This Keynote Paper is concerned with the fundamental mechanics of granular materials with a particular reference to non-coaxial behaviour. The non-coaxial behaviour refers to the non-coincidence of principal stress directions and corresponding principal plastic strain rate directions during plastic deformation. At present, the majority of soil models used in geotechnical practice are those of a...

The use of kinetic equations of NO3- transport systems in oilseed rape (Brassica napus), determined by 15NO3- labeling under controlled conditions, combined with experimental field data from the INRA-Châlons rape database were used to model NO3- uptake during the plant growth cycle. The quantitative effects of different factors such as day/night cycle, ontogenetic stages, root temperature, phot...

During the flood development in an oil field, the creep characteristic of mudstone is one of the important factors causing casing damage. In this study, based on the theory of fractional order differential and taking into account the creep damage evolution rules, a fractional nonlinear creep-damage model is proposed to reflect the instantaneous deformation in loading processes and the accelerat...

In this paper, the direct differentiation method DDM for finite-element FE response sensitivity analysis is extended to linear and nonlinear FE models with multi-point constraints MPCs . The analytical developments are provided for three different constraint handling methods, namely: 1 the transformation equation method; 2 the Lagrange multiplier method; and 3 the penalty function method. Two n...

Free gas in sandy marine sediments is a common occurrence worldwide. A distinct feature of gassy sand that, under undrained shearing, presence occluded bubbles the pore fluid can increase strength at relatively loose state, while reduce dense sand. Previous theoretical analyses have primarily focused on modelling ‘beneficial’ effect free migrating static liquefaction, with few attempts to descr...

The paper describes first the theoretical framework of a “single layer” three phase material. The formulation is general and particular cases are dry and fully saturated soils. The formulation and discretization of the motion and balance equations is presented. Two constitutive equations are used in the applications described: A brittle model for saturated soils and a Mohr-Coulomb elastoplastic...