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16th european conference on Soil Mechanics and geotechnical engineering, ECSMGE 2015

作者： Frattini, N. Gutjahr, I. Boude, J. SOLETANCHE BACHY Rueil-Malmaison France

ISBN: (纸本)9780727760678

As part of the tramway T6 Project, connecting Chatillon to Viroflay in the Paris region, an underground section was realized in the Viroflay area due to the high urban density. During the design and construction two innovative methods were developed: A self- supporting grout slab for the TBM attack, instead of a diaphragm wall reinforced with GFRP bars supported by temporary struts and combined with grouting, and arched metallic waling beams for the stations realized using the top - down technique which allowed a bigger spacing of the temporary struts and therefore the clearance of the access shafts. © the authors and ICE Publishing: All rights reserved, 2015.

关键词： Grouting

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numerical study of the use of actively-tensioned polymeric strips for reinforced soil walls 16

Numerical study of the use of actively-tensioned polymeric s...

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16th european conference on Soil Mechanics and geotechnical engineering, ECSMGE 2015

作者： Damians, I.P. Bathurst, R.J. Lima, J. Lloret, A. Josa, A. Department of Geotechnical Engineering and Geo-Sciences Universitat Politècnica de Catalunya-BarcelonaTech Barcelona Catalunya Spain Institute of Sustainability Universitat Politècnica de Catalunya-BarcelonaTech Barcelona Catalunya Spain GeoEngineering Centre Queen's University - Royal Military College of Canada KingstonON Canada VSL International Ltd. Barcelona Technical Centre Catalunya Spain

ISBN: (纸本)9780727760678

Polymeric strip reinforced soil walls require a practical method to fix the reinforcement tail-ends in the soil backfill during construction to ensure adequate anchorage and to avoid any slack along the linear reinforcement elements. A number of different techniques are currently used depending on the reinforcement type, arrangement and the contractor. this paper reports the results of a series of numerical simulations that were carried out on an idealized 6 m-high wall with precast partial height facing panels. A different reinforcement pre-tension load was applied to the layers in each simulation case. the results of numerical simulations include the reinforcement axial load distribution, vertical facing load and end-of-construction facing alignment plotted as a function of the reinforcement layer depth location and applied pre-tension load. the results demonstrate that the magnitude of pre-tensioning has a significant effect on wall performance for walls subjected to operational (working stress) conditions at end of construction. © the authors and ICE Publishing: All rights reserved, 2015.

关键词： Reinforcement

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Impact of creep on the behaviour of embankments constructed from chemical gypsum 16

Impact of creep on the behaviour of embankments constructed ...

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16th european conference on Soil Mechanics and geotechnical engineering, ECSMGE 2015

作者： Maček, M. Smolar, J. Petkovšek, A. University of Ljubljana Faculty of Civil and Geodetic Engineering Slovenia

ISBN: (纸本)9780727760678

A major concern that engineers face when assessing by-products as fill material is whether the standard methods of laboratory and field tests, developed for soils, would recognize the specific long term behaviour of different types of by-products. Chemical or synthetic gypsum is a by-product from power utilities and acid neutralization. It is a fine grained, non plastic, uniformly graded silty material. the mechanical properties of chemical gypsum can be measured using standard soil testing methods, which could be modified to measure specific gypsum behaviour. For example, long lasting oedometer tests were performed to study creep behaviour. To further improve the understanding of the behaviour of chemical gypsum, a 12 m high and 125 m long instrumented embankment was constructed, using the red gypsum filter cake as fill material. Instrumentation includes pore pressure meters, vertical and horizontal inclinometers and surface geodetic points. Based on the results of laboratory tests and field experiments, a calibration of numerical models was performed and prediction of structural response of experimental embankment was made. © the authors and ICE Publishing: All rights reserved, 2015.

关键词： Gypsum

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Eurocode 7 and new design challenges using numerical methods with different soil models 16

Eurocode 7 and new design challenges using numerical methods...

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16th european conference on Soil Mechanics and geotechnical engineering, ECSMGE 2015

作者： Katsigiannis, G. Schweiger, H.F. Simpson, B. Ferreira, P. Fuentes, R. Arup London United Kingdom University College of London London United Kingdom Graz University of Technology Graz Austria University of Leeds Leeds United Kingdom

ISBN: (纸本)9780727760678

According to Eurocode 7, soil strength factoring can be achieved by applying the material partial factors to the effective stress parameters c' and φ' or to the undrained shear strength cu. thus, in numerical analyses, material factoring is straightforward for constitutive models with c', φ' or cu as input parameters. While designers often use simple elastic-perfectly plastic soil models for ULS checks, the use of more advanced constitutive models allows real soil behaviour to be simulated more realistically and can have significant advantages. In this paper, the feasible use of different soil models for ULS design, increasing in sophistication, such as the Mohr-Coulomb (MC), the Hardening Soil (HS), the Hardening Small Strain (HSS) and the Soft Soil (SS) models, is highlighted and better understood in the context of the EC7 requirements using deep supported excavation examples in stiff clay. the challenges of factoring undrained shear strength when using effective stress model parameters are also discussed and the effect of the soil model is investigated. © the authors and ICE Publishing: All rights reserved, 2015.

关键词： Constitutive models

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Slope stability analysis for fill slopes using finite element limit analysis 16

Slope stability analysis for fill slopes using finite elemen...

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16th european conference on Soil Mechanics and geotechnical engineering, ECSMGE 2015

作者： Lim, K. Li, A. Lyamin, A. Cassidy, M. Deakin University Geelong Australia University of Newcastle Newcastle Australia University of Western Australia Crawley Australia

ISBN: (纸本)9780727760678

this paper investigates the stability of fill slopes often found in embankment cases where frictional fill materials are placed on purely cohesive undrained clay with increasing strength. By using finite element upper and lower bound limit analysis for this investigation, the limit load can be truly bounded. It is known that two-dimensional analysis yields a more conservative result due to plain strain condition when compared to three-dimensional analysis. therefore, this paper will focus on three-dimensional (3D) slope stability analysis and for comparison purposes two-dimensional analysis results will be employed. In fact, the final results are presented in the form of comprehensive chart solutions for the convenience of practicing engineers during preliminary slope design. the failure mechanism will also be discussed in order to further illustrate the situation during failure. It should be highlighted that the failure mechanisms are obtained through the numerical method itself and no prior assumptions are required, therefore, are more realistic and able to provide a better understanding for the slope failure surfaces. © the authors and ICE Publishing: All rights reserved, 2015.

关键词： numerical methods

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Dynamic compaction of collapsible soils - case study from a motorway project in Romania 16

Dynamic compaction of collapsible soils - case study from a ...

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16th european conference on Soil Mechanics and geotechnical engineering, ECSMGE 2015

作者： Tsitsas, G. Dimitriadi, V. Zekkos, D. Dumitru, M. Ciortan, R. Manea, S. GT Ground Engineering Construction Services Bucharest Romania *** Athens Greece United States of Americ University of Michigan Ann Arbor United States Bucharest University of Construction Romania Corresponding Member of the Romanian Academy of Technical Sciences Romania Construction University Bucharest Romania

ISBN: (纸本)9780727760678

Dynamic compaction is a widely used ground improvement method applicable to a variety of soils including collapsible loess. the paper presents site characterization and ground improvement performance results obtained from a 22 kilometer motorway project in Constanta, Romania. High energy dynamic compaction was utilized to treat 240.000 square meters of ground to depths ranging from 6 to 8 meters in order to reduce settlements and mitigate collapse potential. the field results are compared to the results of a finite difference numerical model, developed to simulate the dynamic compaction. © the authors and ICE Publishing: All rights reserved, 2015.

关键词： Soil mechanics

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Comparison of seismic analysis methods applied to a historical church struck by 2009 L'Aquila earthquake

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BULLETIN OF EARthQUAKE engineering 2015年第12期13卷 3749-3778页

作者： Endo, Yohei Pela, Luca Roca, Pere da Porto, Francesca Modena, Claudio Tech Univ Catalonia UPC BarcelonaTech DEC Dept Barcelona 08034 Spain Univ Padua DICEA Dept I-35131 Padua Italy

this paper presents the seismic assessment of a historical church by means of different analysis methods. the church of San Marco, seriously damaged by 2009 L'Aquila earthquake, Italy, is chosen as case-study. the analysis tools adopted and compared are linear and non-linear kinematic analysis, FEM pushover analysis and FEM nonlinear dynamic analysis. the different methods are evaluated regarding their ability to predict the damage and collapse mechanisms actually caused by the earthquake. the accelerograms of the main shock of the 6th April 2009 L'Aquila earthquake are considered for nonlinear dynamic analysis. the influence of relevant construction features, as original disconnection between parts or RC additions, is analysed into detail. Limit analysis is carried out to understand some of the critical collapse mechanisms which are not clearly revealed by FE analysis. the comparison of the analysis methods indicates advantages and limitations of each approach.

关键词： Masonry Pushover analysis Nonlinear dynamic analysis Limit analysis Damage assessment Collapse mechanism

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numerical development of p-y curves for soft clays 16

Numerical development of p-y curves for soft clays

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16th european conference on Soil Mechanics and geotechnical engineering, ECSMGE 2015

作者： Tzivakos, K.P. Kavvadas, M.J. National Technical University Athens Greece

ISBN: (纸本)9780727760678

the paper presents a 3D numerical study (using the finite element code ABAQUS) of the undrained lateral response of a single, free-head pile under monotonic loading. Soil conditions simulating saturated normally consolidated clays are examined (linearly increasing shear strength with depth). the study first compares the results of several p-y curve methods from the literature (e.g. diagrams of lateral load versus horizontal displacement of the pile head and distributions of the horizontal displacement and bending moment along the pile) and shows that the differences are very significant. Due to these differences, the present study revisits the subject by performing parametric 3D finite element analyses with the objective to develop a new set of p-y curves for saturated normally consolidated clays under undrained lateral loading. Soil behavior is modeled by the Modified Cam-Clay (MCC) constitutive model to investigate the effects of normal compression line slope (X) and critical state line slope (M) on the initial stiffness and the ultimate resistance of the p-y curves. Although the numerical model uses effective stresses, the loading was applied sufficiently rapidly to ensure practically undrained conditions. Interface elements are used along the periphery of the pile in order to simulate separation and slipping effects on the response. Based on the results of the finite element analyses, a new set of p-y curves for soft clays is proposed and the key parameters of the curves are determined. © the authors and ICE Publishing: All rights reserved, 2015.

关键词： Piles

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numerical and analytical modelling of pile-raft interaction in sands 16

Numerical and analytical modelling of pile-raft interaction ...

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16th european conference on Soil Mechanics and geotechnical engineering, ECSMGE 2015

作者： Mascarucci, Y. Mandolini, A. Italy

ISBN: (纸本)9780727760678

For many foundations in sands, a shallow raft alone is often able to provide an adequate bearing capacity;piles are then introduced in order to limit settlements to an acceptable level or to reduce the state of stress into the raft. It clearly follows the need to develop new methods that allow simplified piled raft designs. With this aim, the paper presents a numerical and analytical study of capped bored piles (rafts over a single pile) in sandy soils. Focus is given to the raft effect on pile capacity mobilization. Indeed, to better understand and quantify this effect, parametric analyses have been performed dealing with many capped piles embedded in different soil condition (loose/dense, fine/coarse sands). the results show that mechanical and physical soil properties influence this interaction, which becomes crucial in loose and fine sands. An analytical method, called 3M, is then presented to evaluate shaft capacity of piles underneath the rafts. Such a method is based on the fundamental mechanic behaviour of sands and keeps track of the major mechanisms occurring in the soil close to the pile during loading. It is very simple to be used and requires few, physically based parameters. In the paper, the 3M method is employed to modify the Burland's method (1995), already available for the preliminary design of settlement reducing piles in clays, making it suitable for piled rafts in sands. © the authors and ICE Publishing: All rights reserved, 2015.

关键词： Piles

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New concept of highly integrated MSR-HT PEMFC system for small portable power units 6

New concept of highly integrated MSR-HT PEMFC system for sma...

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6th european Fuel Cell Technology and Applications conference - Piero Lunghi conference, EFC 2015

作者： Lotrič, Andrej Sekavčnik, Mihael Pohar, Andrej Hočevar, Stanko Mebius D.o.o. Na jami 3 LjubljanaSI-1000 Slovenia Faculty of Mechanical Engineering University of Ljubljana Aškerčeva 6 LjubljanaSI-1000 Slovenia Laboratory of Catalysis and Chemical Reaction Engineering National Institute of Chemistry Hajdrihova 19 LjubljanaSI-1000 Slovenia

ISBN: (纸本)9788882863241

In a combined methanol steam reformer (MSR) and a proton exchange membrane fuel cell (PEMFC) stack system the processes are both endothermic and exothermic. Hence, proper thermal integration can help raising the system efficiency. First task was to identify possible configurations and prove the concept of such system with a numerical model. three systems were designed based on different PEMFC stacks. Low-temperature (LT) and conventional high-temperature (cHT) PEMFC stack characteristics were based on available data from commercial suppliers. Also, a novel high-temperature (nHT) PEMFC stack was proposed because its operating temperature coincides with that of MSR. In the systems with HT PEMFC stacks the heat is produced at higher temperature levels and thus it is used more efficiently which is shown in better system efficiencies. Second task is to construct a prototype of such integrated system and experimentally define its characteristics. Also, methods of construction and suitability of materials are to be identified in relation to the operating conditions.

关键词： Steam reforming

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