Dongdong Wang, Zhuoya Li, Youcai Wu

The International Conference on Computational & Experimental Engineering and Sciences, Vol.17, No.4, pp. 107-108, 2011, DOI:10.3970/icces.2011.017.107

Abstract Meshfree methods have experienced substantially fundamental development and various applications. One distinguished advantage for meshfree methods is that they can relieve the mesh tangling burden of FEM and are more suitable for finite deformation analysis. In this work a three dimensional updated Lagrangian Galerkin meshfree formulation with improved computational efficiency is presented to analyze the failure of soil slopes. This nonlinear meshfree formulation is featured by the Lagrangian stabilized conforming nodal integration method where the low cost nature of nodal integration approach is kept and at the same time the numerical stability is obtained as is not the case for… More >

Alexander G. TYAPIN

The International Conference on Computational & Experimental Engineering and Sciences, Vol.18, No.2, pp. 51-52, 2011, DOI:10.3970/icces.2011.018.051

Abstract The author extends the previously proposed combined asymptotic method of seismic SSI analysis for the multiply-supported structures. One of the examples of such structures in Nuclear Power Plant is the transportation portal linked to the reactor building by horizontal beams.
The first step still is (like for single-base structure) to develop the dynamic stiffness matrices condensed to the rigid contact surfaces in the frequency domain separately for the soil foundation and for the structure.
For the soil foundation special computer codes like SASSI are used for this purpose. Seismic forces acting to the fixed basements from the soil are… More >

Yuzhou Sun¹, Yuchao Mu²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.1, pp. 115-115, 2019, DOI:10.32604/icces.2019.05304

Abstract Due to its double-structure property, the higher-order continuum theory is adopted to study the constitutive behavior of expansive soil. The higher-order strain and scale factor are considered to describe the effect of the microscale structural property on the macroscale behavior, and a higher-order multiscale constitutive model is developed for expansive soil. The effect of the microscale structural property is investigated through the theoretical and experimental studies based on the developed model. In virtue of a representative elementary volume, the double-structure property is better studied for expansive soil. A variational equation is developed with the contribution of the liquid and gas… More >

X. Liu, A. Scarpas¹

CMES-Computer Modeling in Engineering & Sciences, Vol.9, No.1, pp. 57-74, 2005, DOI:10.3970/cmes.2005.009.057

Abstract Numerical investigations of strain localization have been performed on 3D dense fully saturated sand specimens subjected to triaxial loading and simultaneous inflow or outflow conditions. The role of the water suction field on the formation and evolution of strain localization is addressed computationally. It has been shown that, in a porous medium, the fluid (water) phase plays indeed an important role in strain localization. The formation and evolution of strain localization are influenced both by the material behaviour of the solid component and the interaction between components. In this contribution, after a presentation of the incremental formulation of the coupled… More >

W. J. Ferguson¹, B. Palananthakumar²

CMES-Computer Modeling in Engineering & Sciences, Vol.8, No.3, pp. 201-216, 2005, DOI:10.3970/cmes.2005.008.201

Abstract Environmental and safety issues associated with landfill gas require the control of off-site migration. Mathematical modelling can assist in the understanding of the processes and mechanisms controlling gas migration from municipal waste disposal sites. This paper presents the development and application of a mathematical model that simulates landfill gas migration within a partially saturated soil. This model accounts for two-phase flow and incorporates multi-component (methane, carbon dioxide, dry air and moisture) transport in the gas and liquid phases together with concomitant heat migration. The governing system of fully coupled non-linear partial differential equations of the model have been derived from… More >

Zakia Khelifi^1,2, Mohammed Amine Allal², Nabil Abou-bekr², Saïd Taïbi¹, Benoît Duchemin^1*

Journal of Renewable Materials, Vol.6, No.3, pp. 336-346, 2018, DOI:10.7569/JRM.2018.634102

Abstract The in-soil biodegradation of Stipa tenacissima (alfa) leaves was examined. Non-linear mechanical testing was performed at various biodegradation stages. Tensile strength, loading and unloading Young's moduli and dissipation energy decreased with the burial time, whereas plasticity increased. Field-emission scanning electron microscopy (FE-SEM) showed that the fracture cracks propagated in the longitudinal direction in the raw material, resulting in a fracture mode consisting of a mixture of middle lamella delamination and fiber pull-out. In contrast, the cracks were perpendicular to the stem axis in the biodegraded material, demonstrating an important strength loss of the load-bearing fibers. This strength loss was correlated… More >

Sudhakar Muniyasamy^1,2, Osei Ofosu^1,2, Maya Jacob John^1,2, Rajesh D. Anandjiwala^1,2*

Journal of Renewable Materials, Vol.4, No.2, pp. 133-145, 2016, DOI:10.7569/JRM.2016.634104

Abstract The present study investigates the mineralization of poly(lactic acid) (PLA) and poly(3-hydroxybutyrate-covalerate) (PHBV), and PLA/PHBV blend in compost and soil burial environments. The mineralization was assayed on the basis of carbon dioxide (CO2) release from the test materials incubated in compost and soil for a period of 200 days. The degradation was followed by means of fragmentation, thermogravimetric (TGA), FTIR spectroscopy and scanning electron microscopy (SEM) analyses. The results showed that PLA, PHBV and blend of PLA/PHBV achieved almost 90% biodegradation under composting conditions, while PHBV, PLA/PHBV blend and PLA respectively achieved only 35%, 32% and 4% biodegradation under soil… More >

Zhijian Qiu¹, Jinchi Lu¹, Ahmed Elgamal^1,*, Lei Su², Ning Wang³, Abdullah Almutairi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.3, pp. 629-656, 2019, DOI:10.32604/cmes.2019.05759

Abstract The OpenSees computational platform has allowed unprecedented opportunities for conducting seismic nonlinear soil-structure interaction simulations. On the geotechnical side, capabilities such as coupled solid-fluid formulations and nonlinear incremental-plasticity approaches allow for representation of the involved dynamic/seismic responses. This paper presents recent research that facilitated such endeavors in terms of response of ground-foundation-structure systems using advanced material modeling techniques and high-performance computing resources. Representative numerical results are shown for large-scale soil-structure systems, and ground modification liquefaction countermeasures. In addition, graphical user interface enabling tools for routine usage of such 3D simulation environments are presented, as an important element in support of… More >

Tingjin Liu^1,2, Siyuan Zheng³, Xinwei Tang^1,2,3,*, Yichao Gao⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.3, pp. 545-560, 2019, DOI:10.32604/cmes.2019.05043

Abstract Based on the modified scale boundary finite element method and continued fraction solution, a high-order doubly asymptotic transmitting boundary (DATB) is derived and extended to the simulation of vector wave propagation in complex layered soils. The high-order DATB converges rapidly to the exact solution throughout the entire frequency range and its formulation is local in the time domain, possessing high accuracy and good efficiency. Combining with finite element method, a coupled model is constructed for time-domain analysis of underground station-layered soil interaction. The coupled model is divided into the near and far field by the truncated boundary, of which the… More >

Sunil Kr. Jha¹, Zulfiqar Ahmad²

CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.4, pp. 443-459, 2017, DOI:10.3970/cmes.2017.113.443

Abstract Microbial population and enzyme activities are the significant indicators of soil strength. Soil microbial dynamics characterize microbial population and enzyme activities. The present study explores the development of efficient predictive modeling systems for the estimation of specific soil microbial dynamics, like rock phosphate solubilization, bacterial population, and ACC-deaminase activity. More specifically, optimized subtractive clustering (SC) and Wang and Mendel's (WM) fuzzy inference systems (FIS) have been implemented with the objective to achieve the best estimation accuracy of microbial dynamics. Experimental measurements were performed using controlled pot experiment using minimal salt media with rock phosphate as sole carbon source inoculated with… More >