Constitutive modeling of geotextile-wrapped soil based on insights from DEM analysis
We develop a constitutive model for geotextile-reinforced soil based on insights from DEM analysis of soil–geotextile interface friction, principal stress directions, and stress–dilatancy relationship. From the simulation data, a unique relationship between near-failure stress ratio and near-failure dilation ratio is uniquely defined, independent of the tensile stiffness of the geotextile.
From these new findings, the assumptions on the stress-state evolution and the stress–dilatancy relation are developed accordingly, and the wrapped granular soil can therefore be modeled as a Mohr–Coulomb elastoplastic solid with evolving stress ratio and dilation rate. The development of the proposed constitutive model also demonstrates an innovative approach to take advantage of multiscale insights for the constitutive modeling of complex geomaterials. The constitutive model is validated with the DEM simulation results of geotextile-wrapped soil under uniaxial and triaxial compression, considering a wide range of geotextile tensile stiffness. A good agreement between the DEM data and constitutive model predictions.
From these new findings, the assumptions on the stress-state evolution and the stress–dilatancy relation are developed accordingly, and the wrapped granular soil can therefore be modeled as a Mohr–Coulomb elastoplastic solid with evolving stress ratio and dilation rate. The development of the proposed constitutive model also demonstrates an innovative approach to take advantage of multiscale insights for the constitutive modeling of complex geomaterials. The constitutive model is validated with the DEM simulation results of geotextile-wrapped soil under uniaxial and triaxial compression, considering a wide range of geotextile tensile stiffness. A good agreement between the DEM data and constitutive model predictions.
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A simple multi-scale model for granular soils with geosynthetic Inclusion
The presence of geosynthetics complicates the stress history and fabric evolution of the reinforced soil, posing an obstacle to its constitutive modeling. To circumvent this difficulty, we develop a multiscale model based on a coupled FEM/DEM approach. The displacement in granular soil domain is solved in the hierarchical multiscale framework, while the geosynthetic inclusion that prescribes the boundary conditions are modeled concurrently by discrete bar elements. The responses of both multiscale domains are communicated and updated in an explicit time integration scheme. The predicative capacity of this model is examined in two numerical examples, i.e., pull-in and pull-out tests, which provides a multi-scale understanding of the reinforcement mechanisms.
Deformation at the macro scale during pull-in |
Rigid-body rotation at the macro scale during pull-in |
Deformation at the macro scale during pull-out |
Rigid-body rotation at the macro scale during pull-out |