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Static Analysis of Functionally graded Sandwich Plates Using an Efficient and Simple Refined Theory

Chinese Journal of Aeronautics 2011年第4期24卷 432-433页

作者： Hadj Henni ABdeLAZIZ Hassen Ait ATMANE Ismail MECHAB Lakhdar BOUMIA Abdelouahed TOUNSI Adda Bedia El ABBAS laboratoire des Matériaux et Hydrologie Université de Sidi Bel Abbes Département de génie civil Université Ibn Khaldoun Département de génie civil Faculté de Génie Civil et d'Architecture Univesité de Chlef Département de Physique Université de Sidi Bel Abbes

In this paper, a new displacement based high-order shear deformation theory is introduced for the static response of functionally graded sandwich plate. Unlike any other theory, the number of unknown functions involved is only four, as against five in case of other shear deformation theories. The theory presented is variationally consistent, has strong similarity with classical plate theory in many aspects, does not require shear correction factor, and gives rise to transverse shear stress variation such that the transverse shear stresses vary parabolically across the thickness satisfying shear stress free surface conditions. Two common types of functionally graded sandwich plates, namely, the sandwich with fimctionally graded facesheet and homogeneous core and the sandwich with homogeneous facesheet and functionally graded core, are considered. governing equations are derived from the principle of virtual displacements. The closed-form solution of a simply supported rectangular plate subjected to sinu- soidal loading has been obtained by using the Navier method. The validity of the present theory is investigated by comparing some of the present results with those of the classical, the first-order and the other higher-order theories. It can be concluded that the proposed theory is accurate and simple in solving the static bending behavior of functionally graded sandwich plates.

关键词： functionally graded materials sandwich plates refined plate theory bending Navier solution

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Chemical Availability of Cd, Pb and Zn in Anthropogenically Polluted Soil: Assessing the geochemical Reactivity and Oral Bioaccessibility

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Pedosphere 2017年第3期27卷 616-629页

作者： Christophe WATERLOT Francis DOUAY Aurélie PELFRENE Yncréa Hauts-de-France Laboratoire Génie Civil et géo Environnement (LGCgE)

The most recent in vitro tests used to determine metal bioaccessiblility are generally time-consuming and expensive. This study aimed at determining potential relationships between the concentrations of metals extracted using single-extraction methods and the concentrations of bioaccessible metals assessed by a harmonised in vitro test, the Unified BARgE Method （UBM）. A total number of 27 soil samples were collected from kitchen gardens and lawns with various physicochemical parameters and contamination levels. Significant relationships were obtained between Cd, Pb and Zn extracted in gastric and gastrointestinal phases and using single extractions. The best relationhips were established using acetic and citric acids for Cd, whereas for Pb, citric acid and ethylenedi- aminetetraacetic acid （EDTA） were identified as the best extractants. These relationships were improved by means of a linear multiple regression with a downward stepwise procedure involving agronomic parameters （soil cation exchange capacity and assimilated P）. This method highlighted the fact that the cation exchange capacity and P contents in soils were the two main parameters that controlled the human bioaccessibility of Cd, Pb and Zn in the gastric phase. Besides, the metal concentrations extracted with the acetic and citric acids correlated well with the metal concentrations in the gastric and gastrointestinal phases, suggesting that the bioaceessible metals were mainly in a soluble form, weakly bound to the organic matter and associated with the carbonates and the Fe and Mn oxides/hydroxides in soils.

关键词： gastric phase gastrointestinal phase linear multiple regression single extractant urban soil

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Hydraulic properties of dune sand-bentonite mixtures of insulation barriers for hazardous waste facilities

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Journal of Rock Mechanics and geotechnical Engineering 2016年第4期8卷 541-550页

作者： M.K.gueddouda I.goual B.Benabed S.Taibi N.Aboubekr laboratoire de recherche de génie civil Université Amar Teledji laboratoire Ondes et Milieux Complexes Université du Havre laboratoire Eau et Ouvrages dans Leur Environnement Université Abou Bekr Belakid

The material and elastic properties of rocks are utilized for predicting and evaluating hard rock brittleness using artificial neural networks（ANN）. Herein hard rock brittleness is defined using Yagiz＇method. A predictive model is developed using a comprehensive database compiled from 30 years＇ worth of rock tests at the Earth Mechanics Institute（EMI）, Colorado School of Mines. The model is sensitive to density, elastic properties, and P- and S-wave velocities. The results show that the model is a better predictor of rock brittleness than conventional destructive strength-test based models and multiple regression techniques. While the findings have direct implications on intact rock, the methodology can be extrapolated to rock mass problems in both tunneling and underground mining where rock brittleness is an important control.

关键词： Rock brittleness Elastic properties of rocks Mechanical excavation Rock strength

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Free vibration of functionally graded sandwich plates using four-variable refined plate theory

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Applied Mathematics and Mechanics(English Edition) 2011年第7期32卷 925-942页

作者： L.HADJI H.A.ATMANE A.TOUNSI I.MECHAB E.A.ADDA BEDIA laboratoire des Matériaux et Hydrologie Université de Sidi Bel AbbesSidi Bel Abbes 22000Algérie Département de génie civil Université Ibn KhaldounTiaret 14000Algérie Département de génie civil Faculté des Sciences de l'IngénieurUnivesité Hassiba Benbouali de ChlefChlef 02000Algérie

This paper uses the four-variable refined plate theory （RPT） for the free vibration analysis of functionally graded material （FgM） sandwich rectangular plates. Unlike other theories, there are only four unknown functions involved, as compared to five in other shear deformation theories. The theory presented is variationally consistent and strongly similar to the classical plate theory in many aspects. It does not require the shear correction factor, and gives rise to the transverse shear stress variation so that the transverse shear stresses vary parabolically across the thickness to satisfy free surface conditions for the shear stress. Two common types of FgM sandwich plates are considered, namely, the sandwich with the FgM facesheet and the homogeneous core and the sandwich with the homogeneous facesheet and the FgM core. The equation of motion for the FgM sandwich plates is obtained based on Hamilton＇s principle. The closed form solutions are obtained by using the Navier technique. The fundamental frequencies are found by solving the eigenvalue problems. The validity of the theory is shown by comparing the present results with those of the classical, the first-order, and the other higher-order theories. The proposed theory is accurate and simple in solving the free vibration behavior of the FgM sandwich plates.

关键词： functionally graded material (FgM) free vibration sandwich plate refinedplate theory (RPT) Navier solution

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From dredged sediment to supplementary cementitious material:characterization, treatment, and reuse

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International Journal of Sediment Research 2021年第1期36卷 92-109页

作者： Mouhamadou Amar Mahfoud Benzerzour Joelle Kleib Nor-Edine Abriak Univ.Lille IMT Lille Douai Univ.Artois Yncrea Hauts-de-France ULR 4515-LGCg E Laboratoire de Génie Civil et Géo-Environnement

Nowadays,the preservation of natural resources,the reuse,and the recycling of waste and by-products in the cement industry are gaining increasing attention in a sustainable development *** this perspective,many studies focus on finding solutions in order to propose environmentally friendly *** the sediments represent a way to preserve the natural resources by their reuse as a secondary raw material in multiple applications(concrete,roads,landscaped mound,etc).However,they commonly contain contaminants,organic matter(5%-30%),high water content(50%-200%),and relatively small particle size(Dmax ≤300 μm).Therefore to improve the mechanical properties of this material as well as its physiochemical ones,specific methods of characterization and appropriate treatment techniques(calcination,chemical treatment,etc.) are *** article presents a bibliographical review of the efficient use of sediments in cementitious *** details experimental tests that must be performed to ensure the durability of sediment-based structure and assess their environmental impact under prescribed conditions.

关键词： Sediment Characterization Calcination Pozzolanicity Durability

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Effect of initial gravimetric water content and cyclic wetting-drying on soil-water characteristic curves of disintegrated carbonaceous mudstone

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Transportation Safety and Environment 2019年第3期1卷 230-240页

作者： Ling Zeng Fan Li Jie Liu Qianfeng gao Hanbing Bian School of civil Engineering Changsha University of Science&Technology School of Traffic&Transportation Engineering Changsha University of Science&Technology laboratoire de génie civil et géo-Environnement Universitéde Lille

The soil-water characteristic curve(SWCC)is often used to estimate unsaturated soil properties(***,permeability,volume change,solute and thermal diffusivity).The SWCC of soil samples is significantly affected by cyclic *** examine how water content and cyclic wetting-drying affect the SWCC of disintegrated carbonaceous mudstone(DCM),SWCC tests were implemented using a pressure-plate *** addition,SWCC models for DCM considering the initial gravimetric water content and cyclic wetting-drying were *** test results showed that the volumetric water content(θ)of the DCM first decreased rapidly and then became stable as matric suction(s)*** initial water content affected the SWCC by altering the pore structure of the *** a given number of wetting-drying cycles,the higher the initial water content,the higher the stabilizedθ.At a given s value,θdecreased as the number of wetting-drying cycles increased,which suggests that cyclic wetting-drying reduces the water-holding capacity of *** gardner model for DCM was constructed considering initial water content and cyclic wetting-drying,and was effective at describing and predicting the SWCC model for DCM.

关键词： embankment engineering disintegrated carbonaceous mudstone soil-water characteristic curve initial gravimetric water content cyclic wetting-drying

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Impact of a Phosphate Amendment on the Environmental Availability and Phytoavailability of Cd and Pb in Moderately and Highly Carbonated Kitchen garden Soils

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Pedosphere 2017年第3期27卷 588-605页

作者： Christophe WATERLOT Christelle PRUVOT Franck MAROT Francis DOUAY Yncréa Hauts-de-France Laboratoire Génie Civil et géo Environnement (LGCgE) Agence de l’Environnement et de la Matrise de l’Energie (AdeME) Direction Villes et Territoires Durables Services Friches Urbaines et Sites Pollués

The behaviour of metals mainly depends on soil p H, carbonate contents and contamination level, which should be considered for the management of contaminated soils. In this study, kitchen garden topsoils(0–25 cm) were sampled from the area around three smelters in France, with different Cd and Pb contamination levels. Effect of a phosphate amendment(a mixture of diammonium phosphate and hydroxyapatite) on the environmental availability and phytoavailability of Cd and Pb was evaluated by different chemical extractions and cultivating lettuce(Lactuca sativa L.), respectively. Changes in the distribution of Cd and Pb were found in most contaminated soils after phosphate amendment. An increase of Cd and Pb in the residual phase was highlighted in almost all carbonated contaminated soils, whereas a decrease of Pb in the exchangeable, water and acid-soluble phase was observed in most contaminated soils with the lowest carbonate contents. The concentrations of extractable Cd and Pb using calcium chloride and acetic and citric acids generally decreased after the soil amendment. Lettuces grown on amended soils were acceptable for human consumption as regard to Pb concentration. In contrast, some lettuces were unacceptable for human consumption, since the concentrations of Cd in the leaves were higher than the European legislation limit. Surprisingly, in carbonated soils with very low concentration of Cd, the Cd concentrations in lettuce reached up to the European legislation limit, making the lettuce unacceptable for human *** study highlighted the fact that the total metal concentration in soils does not always allow to predict the metal accumulation in the edible parts of vegetables in order to make a judgement about their acceptability or unacceptability for human consumption.

关键词： chemical amendment contamination immobilisation lettuce metal urban soil

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Contamination,Fractionation and Availability of Metals in Urban Soils in the Vicinity of Former Lead and Zinc Smelters,France

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Pedosphere 2013年第2期23卷 143-159页

作者： C.WATERLOT g.BIDAR A.PELFRNE H.ROUSSEL H.FOURRIER F.DOUAY Université Lille Nord de France groupe ISA Equipe Sols et Environnement Laboratoire Génie Civil et géoEnvironnement (LGCgE) Lille Nord de France (EA 4515) Département des Sites et Sols Pollués Agence de I'Environment et de la Matrise de I'Energie (ADEME)

Soil contamination by metals from anthropogenic activities （e.g., mining and smelting） is a major concern for the environment and human health. Environmental availability of cadmium （Cd）, lead （Pb）, zinc （Zn）, copper （Cu）, and indium （In） in 27 urban soils located around two former Pb and Zn smelters in Northern France were studied by analysing the chemical forms of these metals and evaluating their phytoavailability. These metals were determined using flame or electrothermal absorption atomic spectrometry （FAAS or ETAAS）, depending on their concentration levels. After optimisation of the ETAAS method, characteristic mass of In in water and aqua regia were 9.9 and 18 pg, respectively, showing the high sensitivity of the analytical procedure. Metal partitioning was conducted using a four-step sequential extraction procedure. The results showed that Cd and Zn were mainly in the acid-extractable and reducible forms in the urban soils studied. In contrast, Pb and In were largely in the reducible fraction. However, in some samples, the amount of In extracted in the residual or exchangeable fraction was higher than that in the reducible fraction. Copper was mainly found in the reducible and residual fractions. A pot experiment was conducted in a glasshouse with seven soils （six contaminated and one uncontaminated） and two plant species, ryegrass and lettuce. The results showed transfer of metals from the contaminated soils to the shoots of ryegrass and the edible part of lettuce. The metal bioconcentration factor was in the order of Cd 〉〉 Cu 〉 In 〉 Zn 〉〉 Pb for lettuce leaves, whereas for ryegrass shoots, three orders were found, Cd 〉 Zn 〉 Cu 〉〉 In 〉 Pb, Cd 〉〉 In 〉 Zn 〉 Cu 〉〉Pb, and Zn 〉 Cd 〉 Cu 〉 In 〉〉 Pb, depending on the physico-chemical properties of the soils, such as pH, cation exchange capacity, carbonates, and organic matter. It was established that the metal toxicity was related to the contamination levels and the physico-chemical properties, including pH, organi

关键词： bioconcentration factor environmental availability metal toxicity sequential extraction soil physico-chemical property

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Mechanical Properties of Soil-Rock Mixture Filling in Fault Zone Based on Mesostructure

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Computer Modeling in Engineering & Sciences 2022年第8期132卷 681-705页

作者： Mei Tao Qingwen Ren Hanbing Bian Maosen Cao Yun Jia department of Engineering Mechanics Hohai UniversityNanjing210098China laboratoire de genie civil et g´eo-Environnement Universite de LilleLille59000France laboratoire de Mecanique MultiphysiqueMulti-´echelleUniversite de LilleLille59000France

Soil-rock mixture(SRM)filling in fault zone is an inhomogeneous geomaterial,which is composed of soil and rock *** controls the deformation and stability of the abutment and dam foundation,and threatens the long-term safety of high arch *** study the macroscopic and mesoscopic mechanical properties of SRM,the development of a viable mesoscopic numerical simulation method with a mesoscopic model generation technology,and a reasonable parametric model is crucially desired to overcome the limitations of experimental conditions,specimen dimensions,and experiment *** this end,this study presents a mesoscopic numerical method for simulating the mechanical behavior of SRM by proposing mesoscopic model generation technology based on its mesostructure features,and a rock parameter model considering size *** validity and rationality of the presented mesoscopic numerical method is experimentally verified by the triaxial compression tests with different rock block contents(RBC).The results indicate that the rock block can increase the strength of SRM,and it is proved that the random generation technique and the rock parameter model considering size effect are ***,there are multiple failure surfaces for inhomogeneous geomaterial of SRM,and the angle of the failure zone is no longer 45◦.The yielding zones of the specimen are more likely to occur in thin sections of soil matrix isolated by blocks with the failure path avoiding the rock *** proposed numerical method is effective to investigate the meso-damage mechanism of SRM.

关键词： Soil-rock mixture(SRM) triaxial compression tests random generation technique mesostructure rock parameter model size effect finite element method

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Pseudo-static stability analysis of rock slopes reinforced by passive bolts using the generalized Hoek-Brown criterion

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Journal of Rock Mechanics and geotechnical Engineering 2017年第4期9卷 659-670页

作者： Mounir Belghali Zied Saada denis garnier Samir Maghous laboratoire de génie civil ENIT Université de Tunis El Manar Tunis Tunisia Université Paris-Est Laboratoire Navier (UMR8205) ENPC-IFSTTAR-CNRS Marne-la-Vallée France department of civil Engineering Federal University of Rio Grande do Sul Av. Osvaldo Aranha 99 Porto Alegre RS 90350-190 Brazil

The stability analysis of passive bolt-reinforced rock slopes under seismic loads is investigated within the framework of the kinematic approach of limit analysis theory.A pseudo-static method is adopted to account for the inertial forces induced in the rock mass by seismic *** strength properties of the rock material are described by a modified Hoek-Brown strength criterion,whereas the passive bolts are modeled as bar-like inclusions that exhibit only resistance to tensile-compressive *** advantage of the ability to compute closed-form expressions for the support functions associated with the modified Hoek-Brown strength criterion,a rotational failure mechanism is implemented to derive rigorous lower bound estimates for the amount of reinforcement strength to prevent slope *** approach is then applied to investigating the effects of relevant geometry,strength and loading parameters in light of a preliminary parametric *** accuracy of the approach is assessed by comparison of the lower bound estimates with finite element limit analysis solutions,thus emphasizing the ability of the approach to properly predict the stability conditions and to capture the essential features of deformation localization ***,the extension of the approach to account for slipping at the interface between reinforcements and surrounding rock mass is outlined.

关键词： Reinforced rock slope Modified Hoek-Brown criterion Seismic loading Limit analysis Rotational failure mechanism

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