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ENGINEERING (1213 journals)                  1 2 3 4 5 6 7 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 7)
3D Research     Hybrid Journal   (Followers: 19)
AAPG Bulletin     Hybrid Journal   (Followers: 7)
AASRI Procedia     Open Access   (Followers: 15)
Abstract and Applied Analysis     Open Access   (Followers: 3)
Aceh International Journal of Science and Technology     Open Access   (Followers: 2)
ACS Nano     Full-text available via subscription   (Followers: 254)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 2)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access  
Active and Passive Electronic Components     Open Access   (Followers: 7)
Adaptive Behavior     Hybrid Journal   (Followers: 11)
Adıyaman Üniversitesi Mühendislik Bilimleri Dergisi     Open Access  
Adsorption     Hybrid Journal   (Followers: 4)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 6)
Advanced Science     Open Access   (Followers: 5)
Advanced Science Focus     Free   (Followers: 3)
Advanced Science Letters     Full-text available via subscription   (Followers: 9)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 7)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 18)
Advances in Calculus of Variations     Hybrid Journal   (Followers: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 6)
Advances in Complex Systems     Hybrid Journal   (Followers: 7)
Advances in Engineering Software     Hybrid Journal   (Followers: 27)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 11)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 22)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 27)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 10)
Advances in Natural Sciences: Nanoscience and Nanotechnology     Open Access   (Followers: 30)
Advances in Operations Research     Open Access   (Followers: 12)
Advances in OptoElectronics     Open Access   (Followers: 5)
Advances in Physics Theories and Applications     Open Access   (Followers: 12)
Advances in Polymer Science     Hybrid Journal   (Followers: 41)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Remote Sensing     Open Access   (Followers: 40)
Advances in Science and Research (ASR)     Open Access   (Followers: 6)
Aerobiologia     Hybrid Journal   (Followers: 2)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 6)
AIChE Journal     Hybrid Journal   (Followers: 32)
Ain Shams Engineering Journal     Open Access   (Followers: 5)
Akademik Platform Mühendislik ve Fen Bilimleri Dergisi     Open Access   (Followers: 1)
Alexandria Engineering Journal     Open Access   (Followers: 1)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 28)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 11)
American Journal of Engineering Education     Open Access   (Followers: 9)
American Journal of Environmental Engineering     Open Access   (Followers: 17)
American Journal of Industrial and Business Management     Open Access   (Followers: 23)
Analele Universitatii Ovidius Constanta - Seria Chimie     Open Access  
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 2)
Annals of Regional Science     Hybrid Journal   (Followers: 8)
Annals of Science     Hybrid Journal   (Followers: 7)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 6)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 18)
Applied Clay Science     Hybrid Journal   (Followers: 5)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 12)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4)
Applied Nanoscience     Open Access   (Followers: 8)
Applied Network Science     Open Access   (Followers: 1)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 5)
Applied Physics Research     Open Access   (Followers: 3)
Applied Sciences     Open Access   (Followers: 2)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 5)
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4)
Archives of Foundry Engineering     Open Access  
Archives of Thermodynamics     Open Access   (Followers: 8)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ASEE Prism     Full-text available via subscription   (Followers: 3)
Asia-Pacific Journal of Science and Technology     Open Access  
Asian Engineering Review     Open Access  
Asian Journal of Applied Science and Engineering     Open Access   (Followers: 1)
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 8)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Current Engineering & Maths     Open Access  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 8)
Assembly Automation     Hybrid Journal   (Followers: 2)
at - Automatisierungstechnik     Hybrid Journal   (Followers: 1)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Full-text available via subscription   (Followers: 2)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 9)
Avances en Ciencias e Ingeniería     Open Access  
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 1)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 5)
Batteries     Open Access   (Followers: 6)
Bautechnik     Hybrid Journal   (Followers: 1)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 24)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 4)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Motor Trade Survey     Full-text available via subscription   (Followers: 1)
BER : Retail Sector Survey     Full-text available via subscription   (Followers: 2)
BER : Retail Survey : Full Survey     Full-text available via subscription   (Followers: 2)
BER : Survey of Business Conditions in Manufacturing : An Executive Summary     Full-text available via subscription   (Followers: 3)
BER : Survey of Business Conditions in Retail : An Executive Summary     Full-text available via subscription   (Followers: 4)
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Biofuels Engineering     Open Access   (Followers: 1)
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 10)
Biomedical Engineering     Hybrid Journal   (Followers: 15)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 14)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 18)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 34)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 9)
Biomedical Science and Engineering     Open Access   (Followers: 4)
Biomedizinische Technik - Biomedical Engineering     Hybrid Journal  
Biomicrofluidics     Open Access   (Followers: 4)
BioNanoMaterials     Hybrid Journal   (Followers: 2)
Biotechnology Progress     Hybrid Journal   (Followers: 39)
Boletin Cientifico Tecnico INIMET     Open Access  
Botswana Journal of Technology     Full-text available via subscription   (Followers: 1)
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 14)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 14)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers, Droit, Sciences et Technologies     Open Access  
Calphad     Hybrid Journal  
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 30)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 44)
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 8)
Case Studies in Thermal Engineering     Open Access   (Followers: 4)
Catalysis Communications     Hybrid Journal   (Followers: 6)
Catalysis Letters     Hybrid Journal   (Followers: 2)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 8)
Catalysis Science and Technology     Free   (Followers: 8)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 3)
Catalysis Today     Hybrid Journal   (Followers: 7)
CEAS Space Journal     Hybrid Journal   (Followers: 2)
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 3)
Central European Journal of Engineering     Hybrid Journal   (Followers: 1)
CFD Letters     Open Access   (Followers: 6)
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 2)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 2)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencias Holguin     Open Access   (Followers: 1)
CienciaUAT     Open Access  
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Full-text available via subscription   (Followers: 11)
CIRP Journal of Manufacturing Science and Technology     Full-text available via subscription   (Followers: 14)
City, Culture and Society     Hybrid Journal   (Followers: 24)
Clay Minerals     Full-text available via subscription   (Followers: 10)
Clean Air Journal     Full-text available via subscription   (Followers: 2)
Coal Science and Technology     Full-text available via subscription   (Followers: 3)
Coastal Engineering     Hybrid Journal   (Followers: 11)
Coastal Engineering Journal     Hybrid Journal   (Followers: 5)
Coatings     Open Access   (Followers: 4)
Cogent Engineering     Open Access   (Followers: 2)
Cognitive Computation     Hybrid Journal   (Followers: 4)
Color Research & Application     Hybrid Journal   (Followers: 2)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 14)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 13)
Communications Engineer     Hybrid Journal   (Followers: 1)
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 27)
Composite Interfaces     Hybrid Journal   (Followers: 6)
Composite Structures     Hybrid Journal   (Followers: 271)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 199)
Composites Part B : Engineering     Hybrid Journal   (Followers: 256)
Composites Science and Technology     Hybrid Journal   (Followers: 194)
Comptes Rendus Mécanique     Full-text available via subscription   (Followers: 2)
Computation     Open Access  
Computational Geosciences     Hybrid Journal   (Followers: 15)
Computational Optimization and Applications     Hybrid Journal   (Followers: 7)
Computational Science and Discovery     Full-text available via subscription   (Followers: 2)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 8)
Computer Science and Engineering     Open Access   (Followers: 19)
Computers & Geosciences     Hybrid Journal   (Followers: 30)
Computers & Mathematics with Applications     Full-text available via subscription   (Followers: 7)
Computers and Electronics in Agriculture     Hybrid Journal   (Followers: 5)
Computers and Geotechnics     Hybrid Journal   (Followers: 11)
Computing and Visualization in Science     Hybrid Journal   (Followers: 6)
Computing in Science & Engineering     Full-text available via subscription   (Followers: 33)
Conciencia Tecnologica     Open Access  
Concurrent Engineering     Hybrid Journal   (Followers: 3)
Continuum Mechanics and Thermodynamics     Hybrid Journal   (Followers: 8)
Control and Dynamic Systems     Full-text available via subscription   (Followers: 9)
Control Engineering Practice     Hybrid Journal   (Followers: 43)
Control Theory and Informatics     Open Access   (Followers: 8)
Corrosion Science     Hybrid Journal   (Followers: 25)
Corrosion Series     Full-text available via subscription   (Followers: 6)
CT&F Ciencia, Tecnologia y Futuro     Open Access   (Followers: 1)

        1 2 3 4 5 6 7 | Last

Journal Cover Computers and Geotechnics
  [SJR: 2.033]   [H-I: 58]   [11 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0266-352X
   Published by Elsevier Homepage  [3123 journals]
  • Buckling of tapered friction piles in inhomogeneous soil
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): Joon Kyu Lee, Sangseom Jeong, Youngho Kim
      In this paper, an analytical model is developed to estimate the buckling behavior of tapered friction piles fully embedded in inhomogeneous soil. The governing differential equation of the problem is derived with associated boundary conditions and is solved by using the Runge-Kutta method in combination with the Regula-Falsi method. Numerical examples for calculated buckling loads and buckled shapes are given to highlight the introduction of dimensionless variables related to the tapering and shaft friction of the pile, soil inhomogeneity and pile-soil stiffness as well as the degrees of freedom at the both ends of the pile.

      PubDate: 2018-02-05T06:12:06Z
  • Uplift Resistance of Buried Pipelines in Partially Saturated Sands
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): D.J. Robert, N.I. Thusyanthan
      High Pressure and High Temperature (HPHT) oil and gas pipelines are commonly buried subsurface and the depth of burial is determined by upheaval buckling mitigation requirement or legislation requirement. The upheaval buckling mitigation design requires evaluation of uplift resistance of soil in which pipeline is buried. Conventional design guidelines and current analytical models for predicting the soil uplift resistance are based on either dry soil or fully saturated soil. However, onshore pipeline are buried in soils which are often partially saturated. Therefore, current analytical models do not capture the effects of soil saturation on the uplift resistance of buried pipeline. In partially saturated soils, the uplift resistance is greater than that under fully saturated conditions. This is because the water meniscus between soil particles creates an additional normal force due to suction, which in turn makes the soil behaviour stiffer and stronger. This paper presents full scale pipe-soil tests results and finite-element parametric studies conducted to investigate the effects of soil moisture content, dimensionless cover heights (soil cover height to diameter ratio) and soil relative density on the peak uplift resistance of pipes. The results demonstrate that the current available analytical models under-predict the soil peak uplift resistance in partially saturated conditions. Further, the analyzed results are presented as dimensionless design charts and non-linear regression models which can be used to quantify the partial saturation effect on uplift resistance of buried pipes.

      PubDate: 2018-02-05T06:12:06Z
  • Impact of fluid compressibility for plane strain hydraulic fractures
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): Di Wang, Mian Chen, Yan Jin, Andrew P. Bunger
      Growing interest in hydraulic fracturing (HF) using super-critical CO2 (SC-CO2) calls into question the typical HF modeling assumption whereby the fluid compressibility is neglected. This paper models a plane strain HF driven by compressible fracturing fluid including the influence of viscous fluid flow, crack propagation through the host rock, and fluid leakoff into the host rock. The results show that, contrary to a reasonable initial hypothesis that compressibility would be important, in expected real world conditions the fluid compressibility has little impact on fracture propagation.

      PubDate: 2018-02-05T06:12:06Z
  • Dependence of ultimate bearing capacity and failure behavior of T-shaped
           deep cement mixing piles on enlarged cap shape and pile strength
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): Chana Phutthananon, Pornkasem Jongpradist, Phatharaphong Yensri, Pitthaya Jamsawang
      A numerical investigation of the ultimate pile capacity ( Q ult ) and failure behavior of T-shape deep cement mixing (TDM) piles is conducted under equivalent volume. Physical model tests are conducted to verify the numerical findings. The results reveal that both the shape of the enlarged pile cap and pile strength play key roles. Sensitivity analyses indicate that the effects of cap shape and pile strength on the complex load carrying behavior of TDM piles are attributable to changes in failure mode, which depend on the mobilized skin friction and bearing of both the cap and pile body.

      PubDate: 2018-02-05T06:12:06Z
  • Reliability-based design of tunnelling problems and insights for Eurocode
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): Huaxin Liu, Bak Kong Low
      The partial factor design approach has been suggested to replace the factor of safety design in geotechnical practice, such as the Eurocode 7 (EC7) for European countries and the load and resistance factor design (LRFD) for the North America. However, these design codes cover little about rock engineering principles and rock engineers struggle with the application of the partial factor design to rock engineering problems. This paper presents how reliability-based design (RBD) can provide insights to and help the evolution of the partial factor design approach for tunnelling problems. Compared with other reliability methods, the first-order reliability method (FORM) is consistent for different but mathematically equivalent limit state functions. The intuitive expanding ellipsoid perspective and the constrained optimization method for FORM help overcome the conceptual and computational barriers for practitioners. Three case studies are presented to show that RBD via FORM can determine the role (resistance or load factor) of input parameters on a case-by-case basis in ways that prescribed partial factors cannot, including a symmetrical roof wedge above a tunnel, a lined circular tunnel under non-hydrostatic in situ stresses and a circular tunnel reinforced by rockbolts considering multiple failure modes.

      PubDate: 2018-02-05T06:12:06Z
  • FOSM-based shear reliability analysis of CSGR dams using strength theory
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): Jinsheng Jia, Sha Wang, Cuiying Zheng, Zuping Chen, Yang Wang
      The cemented sand, gravel and rock (CGSR) dam is a new type of dam that combines the characteristics of a rigid dam and an embankment dam. Mechanical tests show that the shear strength of CSGR is much lower than that of concrete and present significant discreteness; shear failure of a CSGR dam is more similar to a failure in material than a failure along the contact between two materials and is quite different from the failure of a rigid dam. The rigid equilibrium method (REM), which adopts the parameters φ and C, could cause great calculation error when applied to the stability evaluation of a CSGR dam. Because of the uncertainty of the shearing parameters, reliability theory should be used to analyze the shearing stability of CSGR dams. In this study, shear criteria based on the theories of Mohr Coulomb and double-shear strength failure and the corresponding limit state equations using uniaxial compressive and tensile strength as random variables are proposed to evaluate the shearing stability of CSGR dams; then, the reliability index of above limit state equations is solved using the reliability method of first-order second moment (FOSM) combined with the finite element method; the failure probability can thus be evaluated on a local scale. The FOSM-based method proposed in this study is applied to the case study of Shou Koubao Dam. The conclusions drawn from the results will contribute to the risk analysis of CSGR dams in the future.

      PubDate: 2018-02-05T06:12:06Z
  • Development of new prediction model for capacity of combined pile-raft
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): Ashutosh Kumar, Deepankar Choudhury
      The complex soil-structure interaction factors to estimate load bearing capacity of a combined pile-raft foundation (CPRF) is scarce. A new prediction method is proposed to estimate both Ultimate Limit State (ULS) and Serviceability Limit State (SLS) bearing capacity of CPRF by evaluating the pile-raft and raft-pile interaction factors. The developed model is validated with available experimental results. The simplified expressions for the evaluation of load-sharing ratio and a mobilized factor of safety of CPRF considering the serviceability requirement of the structure are also proposed. It provides a simple design solution for CPRF subjected to vertical loading condition.

      PubDate: 2018-02-05T06:12:06Z
  • A design scheme for geocell-reinforced foundations based on the lower
           bound limit analysis method
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): Mohammad Reza Arvin, Zahra Beigi
      Results of laboratory tests on geocell-reinforced soils indicate negligible change in the internal friction angle and development of an apparent cohesion. If sufficient apparent cohesion to withstand applied loads on foundations can be determined, then a suitable kind of soil-geocell composite may be selected among pretested ones by laboratory means. In the present study, using numerical methods of lower bound limit analysis, the required apparent cohesion in the geocell layer to bear the applied load on strip foundations has been determined by back analysis. Effects of contributing factors were evaluated on the results for single and double layer reinforcements.

      PubDate: 2018-02-05T06:12:06Z
  • Influence of model type, bias and input parameter variability on
           reliability analysis for simple limit states with two load terms
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): Sina Javankhoshdel, Richard J. Bathurst, Brigid Cami
      A general closed-form solution to compute the reliability index of a simple limit state function with two load terms and one resistance term is derived. The formulation considers contributions to margins of safety expressed in probabilistic terms due to the choice of load and resistance models, bias values, dependencies between nominal values and bias, uncertainty in estimates of nominal values for uncorrelated load and resistance terms at time of design, and average margin of safety expressed as the operational factor of safety. A sensitivity analysis and example application demonstrate the quantitative influence of the contributing random variables on reliability index.

      PubDate: 2018-02-05T06:12:06Z
  • Three-dimensional discrete element analysis of triaxial tests and wetting
           tests on unsaturated compacted silt
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): Tao Li, Mingjing Jiang, Colin Thornton
      Three-dimensional DEM (discrete element method) simulations of triaxial tests and wetting tests on unsaturated silt were carried out in order to analyse the macro and microscopic behaviour under triaxial stress conditions. Interparticle adhesive forces were incorporated into a rolling and twisting resistance model to represent the van der Waals and capillary forces. A loose DEM sample was first produced considering rolling and twisting resistance and van der Waals forces to sustain an open structure. A series of pseudo-constant water content triaxial tests were simulated by controlling adhesive forces at contacts using the matric suction and a group of representative soil-water characteristic curves. The wetting tests were performed by quickly and gradually wetting (QW and GW) the unsaturated sample at different deviator stress levels. By introducing adhesive forces at contacts, the simulation reproduces the main mechanical behaviour. In the triaxial tests, Z m (mechanical coordination number) for the unsaturated sample increases rapidly during shear until becoming approximately constant. The induced structural anisotropy (under deviatoric loading) reduces with decrease in water content due to the higher interparticle adhesive forces. In the gradual wetting tests, the deviatoric fabric increases gradually during wetting. The deviator strains induced by QW and GW (loading-wetting sequence) are much larger than for the saturated sample at the same stress state in triaxial tests (wetting-loading sequence).

      PubDate: 2018-02-05T06:12:06Z
  • Upper-bound stability analysis of dual unlined horseshoe-shaped tunnels
           subjected to gravity
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): Jian Zhang, Tugen Feng, Junsheng Yang, Feng Yang, Yufeng Gao
      This study investigates the stability of dual horseshoe-shaped tunnels in cohesive-frictional soils subjected to gravity using an upper-bound finite element method combined with a plastic-dissipation-based mesh adaptive strategy. The results are presented in the form of dimensionless stability numbers, which decrease with C/D and increase with ϕ. The results indicate that the interaction between dual horseshoe-shaped tunnels disappears when their dimensionless center-to-center distance S/D lies approximately in any of the following ranges for C/D: (i) 3.5–4.5 for C/D = 1, (ii) 3.5–6.5 for C/D = 2, (iii) 3.5–9 for C/D = 3, (iv) 4–11 for C/D = 4, and (v) 4–13.5 for C/D = 5.

      PubDate: 2018-02-05T06:12:06Z
  • A high-order local artificial boundary condition for seepage and heat
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): Shuang Luo, Erxiang Song
      A high-order local artificial boundary condition (ABC) with a new approximation scheme is proposed for numerical analyses of seepage and heat transfer in unbounded domains. The proposed ABCs are first derived for a one-dimensional case and then extended to high-dimensional cases and transversely isotropic media. In the derivation, the irrational function in Laplace space with respect to time is approximated through numerical integration. The calculations show that the proposed ABCs provide more satisfactory results than those obtained by using existing approximation methods, especially for long-duration simulations. Moreover, the relation among the calculation accuracy, approximation order, and diffusivity is also investigated.

      PubDate: 2018-02-05T06:12:06Z
  • Undrained stability of strip footing above voids in two-layered clays by
           finite element limit analysis
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): Yao Xiao, Minghua Zhao, Heng Zhao
      Finite element limit analysis (FELA) is used to study the undrained bearing capacity of strip footing above voids in two-layered clays. Based on the FELA results, design charts and equations are provided to calculate the undrained bearing capacity factor Ns . The impact of parameters on Ns also has been investigated, including undrained shear stress ratio of the soil, thickness of the top layer, location, size, width, height and spacing of the voids. The failure mechanisms for a single void maybe classified into three categories: roof failure, combined roof and wall failure, bearing failure without void failure.

      PubDate: 2018-02-05T06:12:06Z
  • A simplified approach to transient flow effects induced by rigid cylinder
           rotation in a porous medium
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): G. Dienstmann, F.S. de Almeida, A. Fayolle, F. Schnaid, S. Maghous
      Drainage conditions associated with loading rate effects during rotation of elements embedded in intermediate permeability soils are fundamental factors in the assessment and analysis of in situ measured properties and foundation design systems. In that context, a simplified model for poromechanical analysis of consolidation induced by rotation of a rigid cylinder embedded within a porous medium is formulated. The approach is closely connected with the concept of deformation plasticity and relies upon the equivalence between the local behavior of a poroplastic material under monotonic loading process and that of an appropriate non-linear fictitious poroelastic behavior. The non-linear poroelastic model is conceived to capture the transient flow effects on the poromechanical response of the soil surrounding the rotating cylinder. Semi-analytical solutions are derived for pore-fluid pressure, displacement and stress distributions, allowing for the evaluation of rate effects in silty soils, with specific application to purely cohesive and frictional materials. The accuracy of the approach is assessed by comparison of model predictions with poroplastic finite element solutions. The results correlating the degree of drainage to normalized rotation velocity derived from proposed model may be a useful support for a wide range of geotechnical applications, such as laterally loaded rigid piles with rotationally pile connections, offshore wind turbines shafts subjected to torque or torsional vibration, rotation of shaft drilling tools and in situ tests subjected to shear.

      PubDate: 2018-02-05T06:12:06Z
  • An Efficient FE model for SSI: Theoretical background and assessment by
           predicting the response of large diameter monopiles supporting OWECs
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): Lalahoum Otsmane, Djillali Amar Bouzid
      An efficient technique called NVSM (Nonlinear Vertical Slices Model) for analyzing soil/structure interaction (SSI) problems is presented. This procedure approximates a full 3D problem into a series of 2D vertical interacting panels which can be solved using a standard 2D FE discretization, while allowing the slices interaction to be accounted for using the finite difference method. Duncan-Chang basic soil model is described first since it is simple to implement in a computer code, then, the extension of the VS Model to deal with nonlinear problems is detailed and supported by a flowchart giving the necessary steps of stress computations. The written Fortran computer code for predicting the response of large diameter monopiles supporting OWTs under combined loading is assessed against three case studies in which the authors used independently powerful commercial packages to study this kind of foundations embedded in offshore subsoils formed mostly of dense sand. An excellent agreement between the present predictions and those of the other numerical codes has been obtained.

      PubDate: 2018-02-05T06:12:06Z
  • On the micro mechanics of yielding and hardening of crushable granular
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): John P. de Bono, Glenn R. McDowell
      Stress path tests are used to investigate the yield surface of a crushable numerical soil. Triaxial samples with isotropic and anisotropic stress histories are examined to determine the nature of the yield surface and to establish what governs yield. Two separate yield surfaces are exposed: a shear yield surface at low p′ and high η which is governed by minor breakage of fine particles, and a compressive yield surface at high p′ and low η, governed by bulk breakage across all particle sizes. The shear yield surface is dependent on stress history, whilst the compressive yield surface is isotropic.

      PubDate: 2018-02-05T06:12:06Z
  • A machine learning approach to energy pile design
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): Nikolas Makasis, Guillermo A. Narsilio, Asal Bidarmaghz
      Incorporating ground heat exchangers (GHEs) into building foundations allows them to also provide thermal energy for space heating and cooling. However, this introduces certain constraints to ground-source heat pump (GSHP) design, such as on the geometry, and thus a different design approach is required. One such approach, introduced in this article, uses machine learning techniques to very quickly and accurately determine the maximum amount of thermal energy that can reasonably be provided. A comprehensive validation of this methodology for energy piles is presented, using different geometries and thermal load distributions, drawing conclusions about how the approach can best be utilised.

      PubDate: 2018-02-05T06:12:06Z
  • Three-dimensional discrete element modeling of direct shear test for
           granular rubber–sand
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): Can Wang, An Deng, Abbas Taheri
      Three-dimensional discrete element modeling of direct shear test conducted on granular rubber–sand is presented. Excellent agreement was attained between the simulation and test results, verifying the model’s capacity of examining mixtures shear behavior. Important particulate-scale observations were attained, including the inter-particle contacts force, particles displacement and rotation, porosity and their variation with rubber particle contents. The observations demonstrate that the rubber particles inclusion amends the mixture stiffness, grading and packing at the particulate level, leading to a corresponding variation in the material shear behavior. Some interesting particulate-level simulations were examined to gain further insight into micro-mechanic characteristics of the mixtures.

      PubDate: 2018-02-05T06:12:06Z
  • Behavior of a multilayered transversely isotropic half space due to
           horizontal transient loadings
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): Zhi Yong Ai, Yang Li, Chun Lin Liu
      Soils and the related structures are deeply influenced by horizontal transient loadings, such as the wind loads and the seismic forces on tall buildings, and the wave forces on offshore structures. So the stresses and displacements caused by horizontal transient loadings are worthy of study. This paper investigates the behavior of a multilayered transversely isotropic half space due to horizontal transient loadings over a circular area by using the analytical layer-element method. Numerical examples are given to make comparisons with ABAQUS and to expound the effect of transient loading characteristic, material anisotropy and loading depth on the behavior of media.

      PubDate: 2018-02-05T06:12:06Z
  • Long-term settlements of a ship lock: Measurements vs. FE-prediction using
           a high cycle accumulation model
    • Abstract: Publication date: May 2018
      Source:Computers and Geotechnics, Volume 97
      Author(s): J. Machaček, T. Wichtmann, H. Zachert, Th. Triantafyllidis
      During their lifetime many geotechnical structures are subject to a high number of repetitive loading cycles with small strain amplitudes, a so-called high-cyclic loading. Well-known examples are foundations for offshore wind turbines exposed to a cyclic loading caused by wind and water waves. In the case of ship locks, being the subject of the present paper, the high-cyclic loading results from the repeated filling and emptying of the lock chamber which leads to a cyclic change of the water pressures acting on the walls and the bottom of the chamber. Generally, a high-cyclic loading may lead to progressive settlements and a tilting of foundations. Up to now, the availability of validated and standardized analysis procedures for the proof of the serviceability limit state for foundations subject to high-cyclic loading is still limited. One procedure which proved good results for that purpose in recent years is a numerical approach based on finite element (FE) calculations using a high-cycle accumulation (HCA) model to predict the long-term behavior of the subsoil. Subject of this contribution is the application of the HCA model in FE simulations of the ship lock Uelzen I, aiming on a further validation of the proposed procedure. This ship is a well documented structure with long-term monitoring, significantly differing from foundations for offshore wind turbines, which were studied for the validation of the HCA-model so far. Simplifications of the subsoil and the determination of the input parameters for the FE simulations are presented. The long-term settlements predicted by the HCA model are compared to field measurements over two decades. Furthermore, a sensitivity study regarding the influence of various parameters on the predicted settlements is shown.

      PubDate: 2018-02-05T06:12:06Z
  • Response to the discussion on “A simple critical state interface model
           and its application in prediction of shaft resistance of non-displacement
           piles in sand” by R.-F. Feng, Q.-Q. Zhang, S.-W. Liu, X.-M. Li
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): Ali Lashkari

      PubDate: 2017-12-27T01:12:25Z
  • Discussion on “A simple critical state interface model and its
           application in prediction of shaft resistance of non-displacement piles in
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): Ruo-feng Feng, Qian-qing Zhang, Shan-wei Liu, Xiao-mi Li
      In a recent paper (Lashkari, 2017), the author proposed a simple constitutive model for predicting the behaviour of a sand-structure interface under the framework of critical state soil mechanics. However, there are some issues, such as the parameters for the proposed interface model and the algorithm used for the pile segment analysis, that should be discussed in detail.

      PubDate: 2017-12-27T01:12:25Z
  • A constitutive model for soil-rockfill mixtures
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): Andrea Brito, João Ribas Maranha, Laura Maria Mello Saraiva Caldeira
      Soil-rockfill mixtures (SRMs) are economical and environmentally friendly materials. Due to the absence in the literature of constitutive models specifically developed and tested for SRMs, a new constitutive model, the Subloading Surface Rockfill Model, is presented. This model allows the occurrence of plastic strains inside the yield surface, inducing a smooth elastic/plastic transition. The results of experimental tests for different coarse fractions (CF) of several SRMs performed on samples from Odelouca Dam are compared with those obtained with this model. The model was able to reproduce reasonably well the response of SRMs considering the intrinsic variability of the tested specimens.

      PubDate: 2017-12-27T01:12:25Z
  • Strength reduction method in Barodesy
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): Barbara Schneider-Muntau, Gertraud Medicus, Wolfgang Fellin
      Strength reduction analysis are very common in geotechnical engineering to define a factor of safety of structures, e.g. slopes. Usually, the Mohr-Coulomb strength parameters friction angle φ ′ and cohesion c ′ are reduced until limit equilibrium is reached. This method is only applicable to material models which utilize a Mohr-Coulomb or similar (e.g. Drucker-Prager) failure criterion. In this article a strength reduction method for the barodetic material model is introduced and the results of slope stability calculations compared with the results with an elasto-plastic material model (Mohr-Coulomb) and with the results of an analytical analysis according to Bishop are presented. The strength reduction method for barodesy has been implemented in the Finite Element code Abaqus.

      PubDate: 2017-12-27T01:12:25Z
  • Underground excavation behaviour in Bangkok using three-dimensional finite
           element method
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): Chhunla Chheng, Suched Likitlersuang
      This study provides evidence that three-dimensional finite element modelling can be effectively applied for deep excavation analysis in Bangkok. The Bangkok subsoils were modelled using the hardening soil model and their parameters were calibrated against the results of laboratory and field tests. A study of a MRT station excavation was initially used to validate the model. The predicted wall movements and surface settlements were compared with the instrument data and two-dimensional analysis from a previous study. Another deep excavation project was selected asan independent study. The result shows that the model can be confidently used for deep excavation analysis.

      PubDate: 2017-12-27T01:12:25Z
  • Including degree of capillary saturation into constitutive modelling of
           unsaturated soils
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): Annan Zhou, Shengshen Wu, Jie Li, Daichao Sheng
      The degree of saturation ( S ) of soil can be separated into two components: the degree of capillary saturation ( S ′ ) that is based on the capillary water and the degree of adsorptive saturation ( S ″ ) that is based on the adsorbed water. This paper discusses the role of the degree of capillary saturation ( S ′ ) in modelling the coupled hydro-mechanical behaviour of unsaturated soils and proposes a new constitutive model for unsaturated soils by using the degree of capillary saturation ( S ′ ) and the effective inter-particle stress ( σ ij ′ ). An enhanced hydraulic model is introduced to describe the hydraulic hysteresis and hydro-mechanical interaction in terms of the degree of capillary saturation ( S ′ ). In the proposed constitutive model, the shear strength, yield stress and deformation behaviour of unsaturated soils are governed directly by the above two constitutive variables, namely σ ij ′ and S ′ . To be in line with the existing finite element frameworks for unsaturated soils, the proposed model is eventually generalised to constitutive functions consisting of only primary variables such as the net stress ( σ ij ), suction ( s ) and degree of saturation ( S ). The typical performance of the model for simulating the characteristic trends of unsaturated soil behaviour is discussed in several different scenarios. The model is then validated against a variety of experimental data in the literature, and the results show that a reasonable agreement can be obtained using this new constitutive model.

      PubDate: 2017-12-27T01:12:25Z
  • Modelling hydro-mechanical reinforcements of plants to slope stability
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): J.J. Ni, A.K. Leung, C.W.W. Ng, W. Shao
      The study investigates plant reinforcement to the stability of coarse-grained soil slopes, exploring the relative contribution of mechanical root reinforcement and hydrological effects of plant-induced matric suction. A numerical model is used to capture both mechanical root reinforcement and hydrological effects, including evapotranspiration with different root architectures and root-induced changes in soil water retention curve and hydraulic conductivity. Mechanical reinforcement is effective only in shallow depths, where the most root biomass exists. Hydrological reinforcement is much more significant in deeper depths (>1m), but this effect could vanish due to root-induced increase in hydraulic conductivity.

      PubDate: 2017-12-27T01:12:25Z
  • Bayesian model comparison and characterization of bivariate distribution
           for shear strength parameters of soil
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): Lei Zhang, Dian-Qing Li, Xiao-Song Tang, Zi-Jun Cao, Kok-Kwang Phoon
      This paper develops a Bayesian approach for model comparison and characterization of the bivariate distribution of c′ and ϕ′ using limited site-specific data. The copula approach is presented to model the bivariate distribution of c′ and ϕ′. The Bayesian model comparison method is developed to select the most probable bivariate distribution model of c′ and ϕ′. The most probable model is used to characterize the joint probability density function (PDF) of c′ and ϕ′ under the Bayesian framework. The developed approach is illustrated and validated using real data of c′ and ϕ′ for clays from the core wall of Xiaolangdi rockfill dam in China.

      PubDate: 2017-12-27T01:12:25Z
  • A simplified prediction method for evaluating tunnel displacement induced
           by laterally adjacent excavations
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): Gang Zheng, Xinyu Yang, Haizuo Zhou, Yiming Du, Jiayu Sun, Xiaoxuan Yu
      This investigation aimed to develop a simplified semi-empirical method of assessing the deformation of tunnels laterally adjacent to excavations. A finite element analysis using the hardening soil model with small-strain stiffness (HSS model) was performed to study the influence of the excavation depth, the horizontal displacements of retaining structures, and the relative tunnel locations on the responses of existing tunnels. A simplified model was developed based on the numerical results, and a database comprising 14 case histories was collected. Comparisons were made with the generated artificial data and the collected case histories to demonstrate the accuracy of the proposed model.

      PubDate: 2017-12-27T01:12:25Z
  • Modification of capillary pressure by considering pore throat geometry
           with the effects of particle shape and packing features on water retention
           curves for uniformly graded sands
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): Hyoung Suk Suh, Tae Sup Yun
      Accurate estimation of capillary pressures at pore throats during pore network simulation is made by acquiring the effective distribution of non-wetting fluid and its effective shape factor. The suggested method is applied to authentic pore structures of synthetically assembled sphere packings and natural sands. Results highlight that the irregularity of pore throat tends to increase as particle shape becomes irregular while the effective shape factor of 0.8 can be consistently applicable regardless of particle shape. The modified water retention curve well captures experimental results. Packing density and gradation effects are less predominant compared with the effect of capillary pressure correction.

      PubDate: 2017-12-27T01:12:25Z
  • Robust estimation of the fracture diameter distribution from the true
           trace length distribution in the Poisson-disc discrete fracture network
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): Amin Hekmatnejad, Xavier Emery, Javier A. Vallejos
      A distribution-free approach is proposed to estimate the fracture size distribution from a given trace length distribution, assuming that the fracture network can be represented by a Poisson-disc model. This approach directly works on the experimental distribution of the observed trace lengths (corrected from sampling biases) and does not need to choose a parametric model for the trace length or fracture diameter distributions. It is more robust than existing models and provides an unbiased estimate of the cumulative distribution function of the fracture diameters. Its simplicity of use, accuracy and versatility are illustrated through synthetic examples.

      PubDate: 2017-12-27T01:12:25Z
  • Sequential reduction of slope stability uncertainty based on temporal
           hydraulic measurements via the ensemble Kalman filter
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): K. Liu, P.J. Vardon, M.A. Hicks
      A data assimilation framework, utilising measurements of pore water pressure to sequentially improve the estimation of soil hydraulic parameters and, in turn, the prediction of slope stability, is proposed. Its effectiveness is demonstrated for an idealised numerical example involving the spatial variability of saturated hydraulic conductivity, k sat . It is shown that the estimation of k sat generally improves with more measurement points. The degree of spatial correlation of k sat influences the improvement in the predicted performance, as does the selection of initial input statistics. However, the results are robust with respect to moderate uncertainty in the spatial and point statistics.

      PubDate: 2017-12-27T01:12:25Z
  • Investigating the scale-dependency of the geometrical and mechanical
           properties of a moderately jointed rock using a synthetic rock mass (SRM)
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): K. Farahmand, I. Vazaios, M.S. Diederichs, N. Vlachopoulos
      A synthetic rock mass (SRM) model coupling discrete fracture networks (DFNs) and a discrete element grain-based model (DEM) is used to characterize the mechanical properties of moderately jointed rockmasses under confined and unconfined conditions. The scale dependency of the rockmass properties is investigated using the concept of representative element volume (REV). The numerical results are compared with the estimated values from empirical methods. It is determined that the empirical Hoek-Brown criterion correctly estimates the unconfined strength of the rockmass with non-persistent joints, while it overestimates the strength under confined conditions. An S-shaped strength envelope is obtained from the numerical results.

      PubDate: 2017-12-27T01:12:25Z
  • Evaluation of interface shear behavior of GFRP soil nails with a
           strain-transfer model and distributed fiber-optic sensors
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): D.S. Xu, H.B. Liu, W.L. Luo
      A glass fiber reinforced polymer (GFRP) material is a newly developed material for slope reinforcement. In this study, distributed optical fiber sensors are developed to characterize the interface shear stress–strain behavior in GFRP soil nails with a strain-transfer model. The GFRP bar with a diameter of 40 mm was used as a reinforcing element in a soil slope subjected to excavations. A newly distributed fiber optic sensors are developed to measure the axial strains of the GFRP reinforcement which was then inserted into a drilled hole together with pressure grouting. The calibration of distributed fiber optic sensors indicated that the strains along the GFRP bar can be accurately measured by the distributed sensors. An analytical strain-transfer model is developed and then verified with a finite element model. The comparisons indicate that the strain-transfer model could be able to obtain the shear strain and stress at the cement grout–soil interface from arbitrary strain of the GFRP bar. Finally, a field project study is conducted for the condition assessment of a GFRP soil nail with the interface shear stress at different excavation depths. The potential failure surface is identified at the position where the maximum shear stress occurs, that is, at the point around 4.5 m away from the soil nail head. Results in terms of the shear stress are able to detect the active and passive zones of the soil nail. A further analysis indicates that the health condition of the GFRP soil nail can be determined with the distributed fiber sensors and strain-transfer model.

      PubDate: 2017-12-27T01:12:25Z
  • Three-dimensional discontinuous deformation analysis based on
           strain-rotation decomposition
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): Huo Fan, Hong Zheng, Jidong Zhao
      The strain and local rotation at any material point in a deformable body can be descripted by the strain-rotation (S-R) decomposition theorem. This paper presents a three-dimensional dynamic deformation formulation based on the S-R decomposition. The three-dimensional dynamic analysis formulation is generic and can be easily implemented into numerical methods. By combining the new formulation with the discontinuous deformation analysis (DDA), a new method named SR-3D-DDA is developed. We further use several examples to demonstrate that the S-R based DDA can help effectively eliminate the nonphysical volume change exhibited by existing DDAs and improve the accuracy of the predictions.

      PubDate: 2017-12-27T01:12:25Z
  • Dynamic assessment of saturated reinforced-soil retaining wall
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): Feifan Ren, Feng Zhang, Guan Wang, Qihua Zhao, Chao Xu
      The dynamic assessment of a saturated reinforced-soil retaining wall (SRS-RW) has drawn considerable interest as several partial or full collapses of retaining walls due to earthquakes occurring during or immediately after heavy rains have been reported. In this study, a centrifuge shaking table test of the dynamic performance of a SRS-RW, in which five shaking waves were sequentially applied in the horizontal direction, was simulated using a dynamic finite element program. In the analysis, a cyclic mobility model was employed to simulate backfilled soil. This model can account for the complicated mechanical behavior of the saturated backfilled soil and described the influences of the stress-induced anisotropy, the density and the structure of the soil in a unified way. The plastic joint elements that transfer only shearing and compressive forces were inserted between the backfilled soil and the reinforcements. By comparing the calculated results with those of the centrifuge shaking table test, the dynamic behavior of the SRS-RW was thoroughly studied and the accuracy of the numerical analysis was proven to be quite satisfactory. Based on these results, numerical tests were also conducted to investigate the dynamic performance of a SRS-RW under realistic ground conditions. Parametric analyses with three different reinforcement patterns were carried out to develop an effective measure for improving the stability and controlling the deformation of SRS-RWs. The main purpose of this study is to establish an effective assessment method for the dynamic behavior of SRS-RWs.

      PubDate: 2017-12-27T01:12:25Z
  • Grain breakage criteria for discrete element models of sand crushing under
           one-dimensional compression
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): Wenbo Zheng, Dwayne D. Tannant
      Frac sand consisting of quartz grains is widely used in hydraulic fracturing of tight shales to prop fractures open. However, the sand can be crushed by high compressive stress acting on the fractures and this reduces the fracture conductivity. In practice, a one-dimensional compression test is widely used to evaluate the crushing resistance of frac sand. This paper presents the results of discrete element modelling of sand crushing calibrated with laboratory data from one-dimensional compression tests. Three criteria for grain breakage that incorporate grain-size dependent particle strength and failure under shearing/tensile conditions were implemented and evaluated in PFC2D. An innovative aspect is linking the breakage of a clustered particle under multiple contacts in PFC2D to grain breakage criteria to examine the applicability of these breakage criteria in grain crushing. A macro-scale calibration demonstrates how incorporation of particle breakage algorithms can allow the PFC2D model to capture the change in particle size distribution as well as the non-linear stress-strain response of sand under high compressive stresses. The calibrated grain breakage criterion was used to study the crushing behaviour and permeability evolution of a mesh 20/40 Jordan frac sand.

      PubDate: 2017-12-27T01:12:25Z
  • Finite element limit analysis of ultimate lateral pressure of XCC pile in
           undrained clay
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): Hang Zhou, Hanlong Liu, Lehua Wang, Gangqiang Kong
      X-section Cast in place Concrete (XCC) pile is a non-cylindrical pile that the cross section not obeying plane rotationally symmetric. In this case, the geometry of cross section as well as the lateral load direction may have influence on the ultimate lateral pressure of XCC pile. This paper presents rigorous upper and lower bound solutions for the ultimate lateral pressure of X-section Cast in place Concrete (XCC) pile in clay through two dimensional plane strain finite element limit analysis (FELA). The geometric effect, lateral load direction and the adhesion factor at the pile-soil interface are selected for parametric study. Subsequently, an empirical closed-form equation of the ultimate lateral pressure factor is proposed for predicting the lateral force acting on a XCC pile in undrained clay. It is found that the XCC pile with relatively small ratio of b/a has larger ultimate lateral pressure than the conventional circular pile under the condition of the same area of cross section.

      PubDate: 2017-12-27T01:12:25Z
  • THM modeling of ground subsidence induced by excavation of subway tunnel
    • Abstract: Publication date: February 2018
      Source:Computers and Geotechnics, Volume 94
      Author(s): Di Wu, Tengfei Deng, Runkang Zhao, Yinghe Wang
      In order to solve the problem of ground traffic congestion, many cities in China (such as Beijing) have constructed or are being building up underground subway transportation networks. The ground settlement or even collapse induced by the excavation of subway tunnels is a crucial issue that directly relates to the safety of the citizens and buildings. The ground subsidence is dependent on the stability of the geotechnical media around the subway tunnels, which is controlled by the thermal (T), hydraulic (H) and mechanical (M) factors and the THM couplings. Therefore, it is essential to analyze the coupled THM effects on the ground subsidence induced by tunneling. A THM coupled model is developed to investigate the ground subsidence induced by the tunnel excavation, and then the outcomes simulated by this model are compared with that obtained from physical simulation experiments. A good agreement is found between the modeling results and measured data, indicating that the developed model is provided with well predicting capability to describe the tunneling induced ground subsidence under the coupled THM effects.

      PubDate: 2017-12-27T01:12:25Z
  • The bearing capacity and failure mechanism of a vertically loaded strip
           footing placed on the top of slopes
    • Abstract: Publication date: February 2018
      Source:Computers and Geotechnics, Volume 94
      Author(s): Haizuo Zhou, Gang Zheng, Xin Yin, Rui Jia, Xinyu Yang
      This study evaluates the bearing capacity and failure mechanism of strip footings placed on the top of slopes. A set of design charts containing the detailed critical failure mechanism information is presented for engineering practice. The results show that six distinct failure modes can be attributed to the bearing capacity of footings or to the slope stability issues based on the contribution of the soil self-weight. The occurrence of toe failure (S) is the threshold between the two geotechnical issues. The analytical solution based on the face failure mode is aconservative solution for bearing capacity issue.

      PubDate: 2017-12-27T01:12:25Z
  • An alternative coupled thermo-hydro-mechanical finite element formulation
           for fully saturated soils
    • Abstract: Publication date: February 2018
      Source:Computers and Geotechnics, Volume 94
      Author(s): Wenjie Cui, David M. Potts, Lidija Zdravković, Klementyna A. Gawecka, David M.G. Taborda
      Accounting for interaction of the soil’s constituents due to temperature change in the design of geo-thermal infrastructure requires numerical algorithms capable of reproducing the coupled thermo-hydro-mechanical (THM) behaviour of soils. This paper proposes a fully coupled and robust THM formulation for fully saturated soils, developed and implemented into a bespoke finite element code. The flexibility of the proposed formulation allows the effect of some coupling components, which are often ignored in existing formulations, to be examined. It is further demonstrated that the proposed formulation recovers accurately thermally induced excess pore water pressures observed in undrained heating tests.

      PubDate: 2017-12-27T01:12:25Z
  • Smoothed Particle Hydrodynamics for investigating hydraulic and mechanical
           behaviour of an embankment under action of flooding and overburden loads
    • Abstract: Publication date: February 2018
      Source:Computers and Geotechnics, Volume 94
      Author(s): M. Gholami Korzani, S.A. Galindo-Torres, A. Scheuermann, D.J. Williams
      Extreme weather events, such as floods, are becoming more frequent in future with all consequences concerning the safety especially of water retaining structures, in particular, levees used as technical flood protection. The knowledge and correct consideration of coupled hydro-mechanical processes influencing the failure and post-failure behaviour of water saturated soils are of paramount significance for the assessment of hydraulically loaded geotechnical structures. This study focuses on the modelling of the processes governing the behaviour of water saturated soils using Smoothed Particle Hydrodynamics (SPH) on the example of a homogeneous embankment under different loading conditions. This paper aims to improve available SPH framework in order to enhance soil-water interaction in this method for geotechnical engineering investigations. To achieve this goal, the suggested approach is validated intensively by various well-known problems. Finally, the verified tool is used to investigate the hydro-mechanical behaviour of homogeneous embankments under simultaneous hydraulic and mechanical loading. The simulation results prove that the suggested approach is capable of simulating relevant hydraulic and mechanical processes governing the deformation behaviour of hydraulically loaded structures beyond the failure point allowing the detailed analysis of the post-failure behaviour characterised by large deformations.

      PubDate: 2017-12-27T01:12:25Z
  • A comparative study of three onshore wind turbine foundation solutions
    • Abstract: Publication date: February 2018
      Source:Computers and Geotechnics, Volume 94
      Author(s): Wael Mohamed, Per-Erik Austrell
      This work focuses on the geotechnical behaviour of three foundation solutions for windmills. The first design is a traditional flat raft, the second is a deep flat raft, and the third is a conical raft. A comparative study between the traditional and the new solutions is performed. A conical raft is used to improve the resistance of the soil–structure interface. It is shown that a conical raft gives a significant decrease of tilting compared to a flat circular raft. The use of a conical raft can thus decrease the dimensions of the foundation which may lead to potential cost reductions.

      PubDate: 2017-12-27T01:12:25Z
  • Micro-mechanical analysis of geomembrane-sand interactions using DEM
    • Abstract: Publication date: February 2018
      Source:Computers and Geotechnics, Volume 94
      Author(s): Shi-Jin Feng, Xin Liu, Hong-Xin Chen, T. Zhao
      Three-dimensional simulations of interface direct shear test between geomembrane and sand are conducted using DEM in this study. An overlapping technique is established to reasonably simulate the roughness of geomembrane surface. The simulation results agree reasonably well with the published experimental results, such as stress-strain relationship, interface shear strength, thickness of shear band. The method is a practical tool to investigate the micro-mechanical interactions between geomembrane and sand, including particle displacement, void ratio and stress state, number of interparticle contacts, and distribution, magnitude and orientation of contact force during the shearing process.

      PubDate: 2017-12-27T01:12:25Z
  • A long term evaluation of circular mat foundations on clay deposits using
           fractional derivatives
    • Abstract: Publication date: February 2018
      Source:Computers and Geotechnics, Volume 94
      Author(s): Cheng-Cheng Zhang, Hong-Hu Zhu, Bin Shi, Behzad Fatahi
      This study proposes to use fractional derivatives to evaluate the long term performance of circular mat foundations overlying clays and also predict the associated ground settlement. Closed form solutions for the deflection and bending moment of foundations and the subsequent reaction of subgrade are obtained with the Mittag–Leffler function. Numerical examples are used to determine how the fractional order affects the time dependent properties of the foundation and ground settlement, and to simulate the case history of a large standpipe constructed over Tertiary sediments. New insights into design and prediction of shallow foundations and ground settlement are also discussed.
      Graphical abstract image

      PubDate: 2017-12-27T01:12:25Z
  • Hydraulic fracturing simulation for heterogeneous granite by discrete
           element method
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): Wei Chen, Heinz Konietzky, Chao Liu, Xin Tan
      In this study, a heterogeneous discrete element model of granite was built considering different mineral contacts, different mineral grains, and the percentages of minerals which were obtained from analysis of the gray-scale values of the rock picture. First, the contacts and grains parameters were fixed by simulating triaxial compression and fracture toughness tests. Then, the permeability of the numerical model was calibrated on constant head tests. Finally, a coupled hydro-mechanical code was used to investigate the hydraulic fracturing under different conditions, considering the influences of permeability, fluid viscosity, fluid injection rate, boundary stress, pre-existing cracks, heterogeneity and weak layer.

      PubDate: 2017-12-12T14:33:04Z
  • Effects of vertical spatial variability on supported excavations in sands
           considering multiple geotechnical and structural failure modes
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): Zhe Luo, Yixiang Li, Shunhua Zhou, Honggui Di
      In this paper, a probabilistic assessment of supported excavations in spatially varied sands is presented. Random finite element modelling (RFEM) is performed to simulate excavation-induced responses. A procedure for automating the Monte Carlo simulation is developed to facilitate the RFEM. The effects of soil vertical spatial variability on several major geotechnical and structural failure modes, including geotechnical ultimate failure, geotechnical serviceability failure, wall bending failure, wall shear failure, and strut buckling failure, are explicitly investigated. This study demonstrates the importance of addressing the spatial variation of soil properties by considering multiple failure modes for complicated soil-structural interaction problems.

      PubDate: 2017-12-12T14:33:04Z
  • A discrete numerical model involving partial fluid-solid coupling to
           describe suffusion effects in soils
    • Abstract: Publication date: March 2018
      Source:Computers and Geotechnics, Volume 95
      Author(s): R. Aboul Hosn, L. Sibille, N. Benahmed, B. Chareyre
      Suffusion is a particular case of internal erosion in soils. It is a particle-scale mechanism involving the selective erosion of fine particles within the matrix of coarse particles under the effect of water seepage. Modifications in the microstructure as a consequence of the loss of a fine fraction may affect both the hydraulic and the mechanical properties of the soil. Thus leading, in some cases, to drastic consequences. In this study, a methodology based on a discrete numerical model is introduced to investigate the initiation and development of suffusion as well as to analyze its effects on the soil mechanical properties. For that purpose, an original numerical extraction procedure was developed allowing us to mimic the suffusion process by taking into account both the microstructure of the granular packing and the hydraulic loading in the suffusion development. Such a procedure is based on a one-way fluid-solid coupling where the interstitial flow is solved with a finite volume approach defined at the pore scale. Numerical soil samples subjected to different hydraulic gradients show that depending on the amount and the role of eroded particles in the granular assembly two distinct responses can be expected. The eroded medium either shows negligible deformations during erosion but then collapses suddenly once sheared or it deforms significantly during erosion and shows more reduced strength once subjected to shear forces. A non-linear relation between the eroded mass and the mechanical properties of the soil was found.

      PubDate: 2017-12-12T14:33:04Z
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Heriot-Watt University
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