Multiscale hydro-mechanical analysis of unsaturated granular materials using bridging scale method. Issue 4 (15th June 2015)

• Record Type: Journal Article
• Authors: Wan, Ke; Li, Xikui
• Editors: Y.T. Feng, Professor Xikui Li, Professor Yuanqiang Tan and Professor Shunying Ji, Professor
• Is Part Of: Engineering computations. Volume 32:Issue 4(2015)
• Page Start: 935
• Page End: 955
• Publication Date: 2015-06-15
• Subjects: Finite element method -- Discrete element method -- Bridging scale method -- Discrete particle assembly -- Unsaturated porous Cosserat continuum; Computer-aided engineering -- Periodicals; Computer graphics -- Periodicals; 620.00285
• DOI: 10.1108/EC-04-2014-0083
• Languages: English
• ISSNs: 0264-4401

Abstract

Abstract : Purpose: – The purpose of this paper is to extend the bridge scale method (BSM) developed for granular materials with only the solid phase to that taking into account the effects of wetting process in porous continuum. The granular material is modeled as partially saturated porous Cosserat continuum and discrete particle assembly in the coarse and fine scales, respectively. Design/methodology/approach: – Based on the mass and momentum conservation laws for the three phases, i.e. the solid skeleton, the pore water and the pore air, the governing equations for the unsaturated porous Biot-Cosserat continuum model in the coarse scale are derived. In light of the passive air pressure assumption, a reduced finite element model for the model is proposed. According to the decoupling of the fine and coarse scale calculations in the BSM, the unsaturated porous Cosserat continuum model using the finite element method and the discrete element model using the discrete element method for granular media are combined. Findings: – The numerical results for a 2D example problem of slope stability subjected to increasing rainfall along with mechanical loading demonstrate the applicability and performance of the present BSM. The microscopic mechanisms of macroscopic shear band developed in the slope are demonstrated. Research limitations/implications: – Do not account for yet the effects of unsaturated pore water in the fine scale. Originality/value: – The novel BSM that couples the Biot-Cosserat porous continuum modeling and the discrete particle assembly modeling in both coarse and fine scales, respectively, is proposed to provide a micro-macro discrete-continuum two-scale modeling approach for numerical simulations of the hydro-mechanical coupling problems in unsaturated granular materials.