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Publisher: Springer-Verlag   (Total: 2329 journals)

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Showing 1 - 200 of 2329 Journals sorted alphabetically
3D Research     Hybrid Journal   (Followers: 19, SJR: 0.214, h-index: 10)
4OR: A Quarterly J. of Operations Research     Hybrid Journal   (Followers: 9, SJR: 1.073, h-index: 25)
AAPS J.     Hybrid Journal   (Followers: 18, SJR: 1.192, h-index: 74)
AAPS PharmSciTech     Hybrid Journal   (Followers: 5, SJR: 0.718, h-index: 54)
Abdominal Imaging     Hybrid Journal   (Followers: 14, SJR: 0.723, h-index: 60)
Abhandlungen aus dem Mathematischen Seminar der Universitat Hamburg     Hybrid Journal   (Followers: 2, SJR: 0.447, h-index: 12)
Academic Psychiatry     Full-text available via subscription   (Followers: 22, SJR: 0.492, h-index: 32)
Academic Questions     Hybrid Journal   (Followers: 7, SJR: 0.135, h-index: 6)
Accreditation and Quality Assurance: J. for Quality, Comparability and Reliability in Chemical Measurement     Hybrid Journal   (Followers: 26, SJR: 0.378, h-index: 30)
Acoustical Physics     Hybrid Journal   (Followers: 10, SJR: 0.355, h-index: 20)
Acoustics Australia     Hybrid Journal  
Acta Analytica     Hybrid Journal   (Followers: 7, SJR: 0.387, h-index: 6)
Acta Applicandae Mathematicae     Hybrid Journal   (Followers: 1, SJR: 0.624, h-index: 34)
Acta Biotheoretica     Hybrid Journal   (Followers: 5, SJR: 0.419, h-index: 25)
Acta Diabetologica     Hybrid Journal   (Followers: 14, SJR: 1.318, h-index: 46)
Acta Endoscopica     Hybrid Journal   (Followers: 1, SJR: 0.113, h-index: 8)
acta ethologica     Hybrid Journal   (Followers: 4, SJR: 0.465, h-index: 23)
Acta Geochimica     Hybrid Journal   (Followers: 3)
Acta Geodaetica et Geophysica     Hybrid Journal   (Followers: 1, SJR: 0.294, h-index: 13)
Acta Geotechnica     Hybrid Journal   (Followers: 6, SJR: 1.818, h-index: 22)
Acta Informatica     Hybrid Journal   (Followers: 5, SJR: 0.524, h-index: 32)
Acta Mathematica     Hybrid Journal   (Followers: 10, SJR: 8.021, h-index: 47)
Acta Mathematica Hungarica     Hybrid Journal   (Followers: 2, SJR: 0.53, h-index: 29)
Acta Mathematica Sinica, English Series     Hybrid Journal   (Followers: 5, SJR: 0.406, h-index: 30)
Acta Mathematica Vietnamica     Hybrid Journal   (SJR: 0.451, h-index: 5)
Acta Mathematicae Applicatae Sinica, English Series     Hybrid Journal   (SJR: 0.22, h-index: 20)
Acta Mechanica     Hybrid Journal   (Followers: 18, SJR: 0.898, h-index: 52)
Acta Mechanica Sinica     Hybrid Journal   (Followers: 4, SJR: 0.426, h-index: 29)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 5, SJR: 0.525, h-index: 18)
Acta Meteorologica Sinica     Hybrid Journal   (Followers: 3, SJR: 0.524, h-index: 14)
Acta Neurochirurgica     Hybrid Journal   (Followers: 6, SJR: 0.833, h-index: 73)
Acta Neurologica Belgica     Hybrid Journal   (SJR: 0.348, h-index: 27)
Acta Neuropathologica     Hybrid Journal   (Followers: 3, SJR: 6.61, h-index: 117)
Acta Oceanologica Sinica     Hybrid Journal   (Followers: 3, SJR: 0.295, h-index: 17)
Acta Parasitologica     Hybrid Journal   (Followers: 9, SJR: 0.581, h-index: 28)
Acta Physiologiae Plantarum     Hybrid Journal   (Followers: 2, SJR: 0.551, h-index: 39)
Acta Politica     Hybrid Journal   (Followers: 13, SJR: 0.658, h-index: 20)
adhäsion KLEBEN & DICHTEN     Hybrid Journal   (Followers: 5, SJR: 0.103, h-index: 4)
ADHD Attention Deficit and Hyperactivity Disorders     Hybrid Journal   (Followers: 20, SJR: 0.871, h-index: 15)
Adhesion Adhesives & Sealants     Hybrid Journal   (Followers: 7)
Administration and Policy in Mental Health and Mental Health Services Research     Partially Free   (Followers: 14, SJR: 0.795, h-index: 40)
Adsorption     Hybrid Journal   (Followers: 4, SJR: 0.774, h-index: 52)
Advances in Applied Clifford Algebras     Hybrid Journal   (Followers: 3, SJR: 0.319, h-index: 15)
Advances in Atmospheric Sciences     Hybrid Journal   (Followers: 34, SJR: 0.959, h-index: 44)
Advances in Computational Mathematics     Hybrid Journal   (Followers: 15, SJR: 1.255, h-index: 44)
Advances in Contraception     Hybrid Journal   (Followers: 2)
Advances in Data Analysis and Classification     Hybrid Journal   (Followers: 53, SJR: 1.113, h-index: 14)
Advances in Gerontology     Partially Free   (Followers: 8, SJR: 0.141, h-index: 3)
Advances in Health Sciences Education     Hybrid Journal   (Followers: 23, SJR: 1.397, h-index: 42)
Advances in Manufacturing     Hybrid Journal   (Followers: 3, SJR: 0.2, h-index: 4)
Advances in Polymer Science     Hybrid Journal   (Followers: 40, SJR: 0.637, h-index: 89)
Advances in Therapy     Hybrid Journal   (Followers: 5, SJR: 0.79, h-index: 44)
Aegean Review of the Law of the Sea and Maritime Law     Hybrid Journal   (Followers: 7)
Aequationes Mathematicae     Hybrid Journal   (Followers: 2, SJR: 0.882, h-index: 23)
Aerobiologia     Hybrid Journal   (Followers: 1, SJR: 0.511, h-index: 36)
Aesthetic Plastic Surgery     Hybrid Journal   (Followers: 8, SJR: 0.821, h-index: 49)
African Archaeological Review     Hybrid Journal   (Followers: 14, SJR: 0.612, h-index: 24)
Afrika Matematika     Hybrid Journal   (Followers: 1, SJR: 0.248, h-index: 6)
AGE     Hybrid Journal   (Followers: 7, SJR: 1.358, h-index: 33)
Ageing Intl.     Hybrid Journal   (Followers: 7, SJR: 0.337, h-index: 10)
Aggiornamenti CIO     Hybrid Journal   (Followers: 1)
Aging Clinical and Experimental Research     Hybrid Journal   (Followers: 3, SJR: 0.529, h-index: 55)
Agricultural Research     Hybrid Journal   (Followers: 3)
Agriculture and Human Values     Hybrid Journal   (Followers: 12, SJR: 1.197, h-index: 49)
Agroforestry Systems     Hybrid Journal   (Followers: 20, SJR: 0.64, h-index: 56)
Agronomy for Sustainable Development     Hybrid Journal   (Followers: 10, SJR: 1.732, h-index: 59)
AI & Society     Hybrid Journal   (Followers: 7, SJR: 0.171, h-index: 19)
AIDS and Behavior     Hybrid Journal   (Followers: 13, SJR: 2.006, h-index: 71)
Air Quality, Atmosphere & Health     Hybrid Journal   (Followers: 3, SJR: 0.706, h-index: 19)
Akupunktur & Aurikulomedizin     Full-text available via subscription   (Followers: 1)
Algebra and Logic     Hybrid Journal   (Followers: 2, SJR: 0.566, h-index: 18)
Algebra Universalis     Hybrid Journal   (Followers: 2, SJR: 0.388, h-index: 22)
Algebras and Representation Theory     Hybrid Journal   (Followers: 1, SJR: 0.868, h-index: 20)
Algorithmica     Hybrid Journal   (Followers: 7, SJR: 0.898, h-index: 56)
Allergo J.     Full-text available via subscription   (Followers: 1, SJR: 0.183, h-index: 20)
Allergo J. Intl.     Hybrid Journal   (Followers: 2)
Alpine Botany     Hybrid Journal   (Followers: 4, SJR: 0.729, h-index: 20)
ALTEX : Alternatives to Animal Experimentation     Open Access   (Followers: 3, SJR: 1.392, h-index: 32)
AMBIO     Hybrid Journal   (Followers: 14, SJR: 1.094, h-index: 87)
American J. of Cardiovascular Drugs     Hybrid Journal   (Followers: 10, SJR: 0.864, h-index: 39)
American J. of Community Psychology     Hybrid Journal   (Followers: 24, SJR: 1.237, h-index: 83)
American J. of Criminal Justice     Hybrid Journal   (Followers: 7, SJR: 0.634, h-index: 13)
American J. of Cultural Sociology     Hybrid Journal   (Followers: 11, SJR: 0.283, h-index: 3)
American J. of Dance Therapy     Hybrid Journal   (Followers: 4, SJR: 0.175, h-index: 13)
American J. of Potato Research     Hybrid Journal   (Followers: 2, SJR: 0.558, h-index: 35)
American J. of Psychoanalysis     Hybrid Journal   (Followers: 21, SJR: 0.293, h-index: 13)
American Sociologist     Hybrid Journal   (Followers: 11, SJR: 0.18, h-index: 13)
Amino Acids     Hybrid Journal   (Followers: 7, SJR: 1.362, h-index: 83)
AMS Review     Partially Free   (Followers: 4)
Analog Integrated Circuits and Signal Processing     Hybrid Journal   (Followers: 5, SJR: 0.21, h-index: 37)
Analysis and Mathematical Physics     Hybrid Journal   (Followers: 4, SJR: 0.665, h-index: 7)
Analysis in Theory and Applications     Hybrid Journal  
Analysis of Verbal Behavior     Hybrid Journal   (Followers: 4)
Analytical and Bioanalytical Chemistry     Hybrid Journal   (Followers: 28, SJR: 1.096, h-index: 123)
Anatomical Science Intl.     Hybrid Journal   (Followers: 2, SJR: 0.301, h-index: 26)
Angewandte Schmerztherapie und Palliativmedizin     Hybrid Journal  
Angiogenesis     Hybrid Journal   (Followers: 3, SJR: 2.212, h-index: 69)
Animal Cognition     Hybrid Journal   (Followers: 15, SJR: 1.122, h-index: 55)
Annales françaises de médecine d'urgence     Hybrid Journal   (Followers: 1, SJR: 0.156, h-index: 4)
Annales Henri Poincaré     Hybrid Journal   (Followers: 3, SJR: 1.377, h-index: 32)
Annales mathématiques du Québec     Hybrid Journal   (Followers: 4)
Annali dell'Universita di Ferrara     Hybrid Journal   (SJR: 0.504, h-index: 14)
Annali di Matematica Pura ed Applicata     Hybrid Journal   (Followers: 1, SJR: 1.167, h-index: 26)
Annals of Behavioral Medicine     Hybrid Journal   (Followers: 12, SJR: 2.112, h-index: 98)
Annals of Biomedical Engineering     Hybrid Journal   (Followers: 18, SJR: 1.182, h-index: 94)
Annals of Combinatorics     Hybrid Journal   (Followers: 3, SJR: 0.849, h-index: 15)
Annals of Data Science     Hybrid Journal   (Followers: 8)
Annals of Dyslexia     Hybrid Journal   (Followers: 9, SJR: 0.857, h-index: 40)
Annals of Finance     Hybrid Journal   (Followers: 28, SJR: 0.686, h-index: 14)
Annals of Forest Science     Hybrid Journal   (Followers: 4, SJR: 0.929, h-index: 57)
Annals of Global Analysis and Geometry     Hybrid Journal   (Followers: 1, SJR: 1.136, h-index: 23)
Annals of Hematology     Hybrid Journal   (Followers: 13, SJR: 1.117, h-index: 62)
Annals of Mathematics and Artificial Intelligence     Hybrid Journal   (Followers: 6, SJR: 0.593, h-index: 42)
Annals of Microbiology     Hybrid Journal   (Followers: 9, SJR: 0.402, h-index: 26)
Annals of Nuclear Medicine     Hybrid Journal   (Followers: 5, SJR: 0.68, h-index: 45)
Annals of Operations Research     Hybrid Journal   (Followers: 8, SJR: 1.186, h-index: 78)
Annals of Regional Science     Hybrid Journal   (Followers: 7, SJR: 0.405, h-index: 42)
Annals of Software Engineering     Hybrid Journal   (Followers: 12)
Annals of Solid and Structural Mechanics     Hybrid Journal   (Followers: 10, SJR: 0.553, h-index: 8)
Annals of Surgical Oncology     Hybrid Journal   (Followers: 11, SJR: 1.902, h-index: 127)
Annals of Telecommunications     Hybrid Journal   (Followers: 7, SJR: 0.315, h-index: 25)
Annals of the Institute of Statistical Mathematics     Hybrid Journal   (Followers: 1, SJR: 0.931, h-index: 31)
Antonie van Leeuwenhoek     Hybrid Journal   (Followers: 5, SJR: 0.992, h-index: 87)
Apidologie     Hybrid Journal   (Followers: 4, SJR: 1.14, h-index: 57)
APOPTOSIS     Hybrid Journal   (Followers: 8, SJR: 1.554, h-index: 87)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 2, SJR: 0.354, h-index: 27)
Applications of Mathematics     Hybrid Journal   (Followers: 1, SJR: 0.274, h-index: 20)
Applied Biochemistry and Biotechnology     Hybrid Journal   (Followers: 44, SJR: 0.575, h-index: 80)
Applied Biochemistry and Microbiology     Hybrid Journal   (Followers: 17, SJR: 0.267, h-index: 26)
Applied Categorical Structures     Hybrid Journal   (Followers: 2, SJR: 0.361, h-index: 21)
Applied Composite Materials     Hybrid Journal   (Followers: 46, SJR: 0.705, h-index: 35)
Applied Entomology and Zoology     Partially Free   (Followers: 2, SJR: 0.554, h-index: 34)
Applied Geomatics     Hybrid Journal   (Followers: 3, SJR: 0.323, h-index: 9)
Applied Geophysics     Hybrid Journal   (Followers: 7, SJR: 0.541, h-index: 13)
Applied Intelligence     Hybrid Journal   (Followers: 14, SJR: 0.777, h-index: 43)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 3, SJR: 0.358, h-index: 34)
Applied Mathematics & Optimization     Hybrid Journal   (Followers: 4, SJR: 0.955, h-index: 33)
Applied Mathematics - A J. of Chinese Universities     Hybrid Journal   (SJR: 0.275, h-index: 8)
Applied Mathematics and Mechanics     Hybrid Journal   (Followers: 4, SJR: 0.37, h-index: 26)
Applied Microbiology and Biotechnology     Hybrid Journal   (Followers: 61, SJR: 1.262, h-index: 161)
Applied Physics A     Hybrid Journal   (Followers: 7, SJR: 0.535, h-index: 121)
Applied Physics B: Lasers and Optics     Hybrid Journal   (Followers: 23, SJR: 0.983, h-index: 104)
Applied Psychophysiology and Biofeedback     Hybrid Journal   (Followers: 7, SJR: 0.677, h-index: 47)
Applied Research in Quality of Life     Hybrid Journal   (Followers: 10, SJR: 0.288, h-index: 15)
Applied Solar Energy     Hybrid Journal   (Followers: 15, SJR: 0.251, h-index: 6)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 4, SJR: 0.351, h-index: 9)
Aquaculture Intl.     Hybrid Journal   (Followers: 22, SJR: 0.613, h-index: 40)
Aquarium Sciences and Conservation     Hybrid Journal   (Followers: 1)
Aquatic Ecology     Hybrid Journal   (Followers: 30, SJR: 0.646, h-index: 44)
Aquatic Geochemistry     Hybrid Journal   (Followers: 3, SJR: 0.764, h-index: 39)
Aquatic Sciences     Hybrid Journal   (Followers: 12, SJR: 1.172, h-index: 53)
Arabian J. for Science and Engineering     Hybrid Journal   (Followers: 5, SJR: 0.345, h-index: 20)
Arabian J. of Geosciences     Hybrid Journal   (Followers: 1, SJR: 0.417, h-index: 16)
Archaeological and Anthropological Sciences     Hybrid Journal   (Followers: 21, SJR: 1.056, h-index: 15)
Archaeologies     Hybrid Journal   (Followers: 12, SJR: 0.397, h-index: 13)
Archiv der Mathematik     Hybrid Journal   (Followers: 1, SJR: 0.597, h-index: 29)
Archival Science     Hybrid Journal   (Followers: 52, SJR: 0.804, h-index: 22)
Archive for History of Exact Sciences     Hybrid Journal   (Followers: 7, SJR: 0.28, h-index: 15)
Archive for Mathematical Logic     Hybrid Journal   (Followers: 1, SJR: 0.946, h-index: 23)
Archive for Rational Mechanics and Analysis     Hybrid Journal   (SJR: 4.091, h-index: 66)
Archive of Applied Mechanics     Hybrid Journal   (Followers: 4, SJR: 0.865, h-index: 40)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 4, SJR: 2.841, h-index: 40)
Archives of Dermatological Research     Hybrid Journal   (Followers: 6, SJR: 0.9, h-index: 65)
Archives of Environmental Contamination and Toxicology     Hybrid Journal   (Followers: 10, SJR: 0.846, h-index: 84)
Archives of Gynecology and Obstetrics     Hybrid Journal   (Followers: 16, SJR: 0.695, h-index: 47)
Archives of Microbiology     Hybrid Journal   (Followers: 8, SJR: 0.702, h-index: 85)
Archives of Orthopaedic and Trauma Surgery     Hybrid Journal   (Followers: 8, SJR: 1.039, h-index: 56)
Archives of Osteoporosis     Hybrid Journal   (Followers: 2, SJR: 1.092, h-index: 13)
Archives of Sexual Behavior     Hybrid Journal   (Followers: 9, SJR: 1.198, h-index: 74)
Archives of Toxicology     Hybrid Journal   (Followers: 16, SJR: 1.595, h-index: 76)
Archives of Virology     Hybrid Journal   (Followers: 5, SJR: 1.086, h-index: 90)
Archives of Women's Mental Health     Hybrid Journal   (Followers: 13, SJR: 1.264, h-index: 50)
Archivio di Ortopedia e Reumatologia     Hybrid Journal  
Archivum Immunologiae et Therapiae Experimentalis     Hybrid Journal   (Followers: 2, SJR: 1.2, h-index: 42)
ArgoSpine News & J.     Hybrid Journal   (SJR: 0.102, h-index: 3)
Argumentation     Hybrid Journal   (Followers: 5, SJR: 0.295, h-index: 18)
Arid Ecosystems     Hybrid Journal   (Followers: 3)
Arkiv för Matematik     Hybrid Journal   (Followers: 1, SJR: 0.948, h-index: 22)
Arnold Mathematical J.     Hybrid Journal   (Followers: 1)
Arthropod-Plant Interactions     Hybrid Journal   (Followers: 1, SJR: 0.797, h-index: 17)
Arthroskopie     Hybrid Journal   (Followers: 1, SJR: 0.145, h-index: 8)
Artificial Intelligence and Law     Hybrid Journal   (Followers: 10, SJR: 0.288, h-index: 25)
Artificial Intelligence Review     Hybrid Journal   (Followers: 15, SJR: 0.948, h-index: 48)
Artificial Life and Robotics     Hybrid Journal   (Followers: 8, SJR: 0.231, h-index: 14)
Asia Europe J.     Hybrid Journal   (Followers: 4, SJR: 0.247, h-index: 9)
Asia Pacific Education Review     Hybrid Journal   (Followers: 9, SJR: 0.371, h-index: 17)
Asia Pacific J. of Management     Hybrid Journal   (Followers: 11, SJR: 1.676, h-index: 50)
Asia-Pacific Education Researcher     Hybrid Journal   (Followers: 11, SJR: 0.353, h-index: 13)
Asia-Pacific Financial Markets     Hybrid Journal   (Followers: 2, SJR: 0.19, h-index: 15)
Asia-Pacific J. of Atmospheric Sciences     Hybrid Journal   (Followers: 20, SJR: 1.006, h-index: 14)
Asian Business & Management     Hybrid Journal   (Followers: 7, SJR: 0.41, h-index: 10)
Asian J. of Business Ethics     Hybrid Journal   (Followers: 7)
Asian J. of Criminology     Hybrid Journal   (Followers: 5, SJR: 0.263, h-index: 8)
AStA Advances in Statistical Analysis     Hybrid Journal   (Followers: 2, SJR: 0.681, h-index: 15)
AStA Wirtschafts- und Sozialstatistisches Archiv     Hybrid Journal   (Followers: 5, SJR: 0.195, h-index: 5)
ästhetische dermatologie & kosmetologie     Full-text available via subscription  
Astronomy and Astrophysics Review     Hybrid Journal   (Followers: 21, SJR: 4.511, h-index: 44)
Astronomy Letters     Hybrid Journal   (Followers: 19, SJR: 0.58, h-index: 30)
Astronomy Reports     Hybrid Journal   (Followers: 12, SJR: 0.473, h-index: 23)
Astrophysical Bulletin     Hybrid Journal   (Followers: 2, SJR: 0.469, h-index: 11)

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Journal Cover Acta Geotechnica
  [SJR: 1.818]   [H-I: 22]   [6 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 1861-1133 - ISSN (Online) 1861-1125
   Published by Springer-Verlag Homepage  [2329 journals]
  • A geotechnical perspective of raw earth building
    • Authors: Domenico Gallipoli; Agostino Walter Bruno; Céline Perlot; Joao Mendes
      Pages: 463 - 478
      Abstract: Abstract Much research has been devoted over the past 30 years to the development of construction materials that can lower the environmental and economic costs of buildings over their entire life by reducing embodied energy, minimizing air conditioning needs and cutting down demolition waste. In this respect, raw earth is an attractive material because it is natural and largely available. In its simplest form, this material consists of a compacted mixture of soil and water which is put in place with the least possible transformation. Raw earth construction has been practised in ancient times but has only recently been rediscovered thanks to modern technology, which has improved fabrication efficiency. If properly manufactured, raw earth exhibits comparable mechanical characteristics and better hygro-thermal properties than concrete or fired bricks. After a brief historical overview, we discuss the advantages of raw earth construction in terms of environmental impact, energy consumption and indoor air quality together with the main obstacles to its wider dissemination. We also review the hydro-thermo-mechanical behaviour of raw earth in the context of the recent geotechnical literature, by examining the dependency of key parameters such as strength, stiffness and moisture retention on: (a) material variables (e.g. particle size and mineralogy), (b) manufacturing variables (e.g. density and stabilization) and (c) environmental variables (e.g. pore suction, ambient humidity and temperature).
      PubDate: 2017-06-01
      DOI: 10.1007/s11440-016-0521-1
      Issue No: Vol. 12, No. 3 (2017)
       
  • Granular contact dynamics with elastic bond model
    • Authors: J. Meng; J. Huang; D. Sheng; S. W. Sloan
      Pages: 479 - 493
      Abstract: Abstract This paper proposes an elastic bond model in the framework of contact dynamics based on mathematic programming. The bond model developed in this paper can be used to model cemented materials. The formulation can be reduced to model pure static problems without introducing any artificial damping. In addition, omitting the elastic terms in the objective function turns the formulation into rigid bond model, which can be used for the modeling of rigid or stiffly bonded materials. The developed bond model has the advantage over the explicit DEM that large time step or displacement increment can be used. The tensile and shear strength criteria of the bond model are formulated based on the modified Mohr–Coulomb failure criterion. The torque transmission of bonds is introduced based on rolling resistance model. The loss of shear or tensile strength, or torque transmission will lead to the breakage of bonds, and turn the bond into purely frictional contact. Three simple examples are first used to validate the bond model. Numerical examples of uniaxial and biaxial compression tests are used to show its potential in modeling cemented geomaterials. Numerical results show that elastic bonds are indeed necessary for the modeling of cemented granular material under static conditions.
      PubDate: 2017-06-01
      DOI: 10.1007/s11440-016-0481-5
      Issue No: Vol. 12, No. 3 (2017)
       
  • DEM simulations of sandstone under true triaxial compressive tests
    • Authors: K. Duan; C. Y. Kwok; X. Ma
      Pages: 495 - 510
      Abstract: Abstract Numerically simulated true triaxial compression tests (σ 1 ≥ σ 2 ≥ σ 3) are conducted in this study to elucidate the failure mechanism of sandstone using 3D discrete element method (DEM), in particular the effect of the intermediate principal stress (σ 2). Eight series of tests (σ 3 = 0, 10, 20, 30, 40, 50, 70, and 100 MPa) are conducted. Within each series, σ 2 is varied from σ 2 = σ 3 to σ 2 = σ 1 from test to test. For each test, σ 1 is raised monotonically to failure while keeping σ 2 and σ 3 constant. The DEM simulations reveal the effect of σ 2 on the variations of peak stress, Young’s modulus, failure plane angles, the brittle–ductile transition, and the evolution of failure modes, the effect beyond the well-understood effect of σ 3. The simulation is in qualitative agreement with the results obtained experimentally. Detailed analyses performed on the particle-scale responses further the understanding of the microscopic mechanisms. The distribution of contact force becomes more homogeneous with the increase of σ 3, which leads to the resulting damage being more localized rather than diffused. The interaction between contact force distribution and coalescence of cracks determines the processes and patterns of fracturing in the sample scale. σ 2 is found to affect the microscopic stress distribution as well as structure evolution, and this effect weakens with the increase of σ 3.
      PubDate: 2017-06-01
      DOI: 10.1007/s11440-016-0480-6
      Issue No: Vol. 12, No. 3 (2017)
       
  • Use of discrete element modeling to study the stress and strain
           distribution in cyclic torsional shear tests
    • Authors: José Francisco Wilson; Esteban Sáez
      Pages: 511 - 526
      Abstract: Abstract In this research, a torsional cyclic shear test was modeled using the 3D discrete element method (DEM). The results are compared against experimental data and micro-mechanical aspects of the soil during the loading are discussed. The aim of the work is to study the homogeneity of strains during this laboratory test and to compare the micro-mechanical behavior of the soil sample for different strain levels. The experimental investigation was performed using a synthetic soil material made of glass beads, which simplifies the modeling and calibration since normal interaction forces do not induce rotation of the particles. Both the model and experimental tests used the same grading distribution and particle size. We showed that the hysteresis cycles can be properly reproduced in terms of shape and magnitude. Thus, we obtained a robust estimation for the secant shear modulus and damping ratio at different strain levels. With this, it was possible to build stiffness degradation and damping increase curve to compare it with experimental data obtained from torsional shear tests. Based on this validation of the DEM model, we discuss the micro-mechanical behavior of the soil and its relation with the macroscopic parameters obtained. It is shown that shear strain distribution on the sample is not uniform and that large values of strains concentrate close to the top of the sample as top rotation increases, which differs from the standard assumption of a constant value across the height of the sample. Additionally, it is observed that at 0.8 times radius, the cumulative torque reaches approximately 90% of the total torque applied to sample.
      PubDate: 2017-06-01
      DOI: 10.1007/s11440-017-0526-4
      Issue No: Vol. 12, No. 3 (2017)
       
  • Three-dimensional DEM investigation of critical state and dilatancy
           behaviors of granular materials
    • Authors: Wei Zhou; Jiaying Liu; Gang Ma; Xiaolin Chang
      Pages: 527 - 540
      Abstract: Abstract The critical state is significant to the mechanical behaviors of granular materials and the foundation of the constitutive relations. Using the discrete element method (DEM), the mechanical behaviors of granular materials can be investigated on both the macroscopic and microscopic levels. A series of DEM simulations under true triaxial conditions have been performed to explore the critical state and dilatancy behavior of granular materials, which show the qualitatively similar macroscopic responses as the experimental results. The critical void ratio and stress ratio under different stress paths are presented. A unique critical state line (CSL) is shown to indicate that the intermediate principal stress ratio does not influence the CSL. Within the framework of the unique critical state, the stress–dilatancy relation of DEM simulations is found to fulfill the state-dependent dilatancy equations. As a microscopic parameter to evaluate the static determinacy of the granular system, the redundancy ratio is defined and investigated. The results show that the critical state is very close to the statically determinate state. Other particle-level indexes, including the distribution of the contact forces and the anisotropies, are carefully investigated to analyze the microstructural evolution and the underlying mechanism. The microscopic analysis shows that both the contact orientations and contact forces influence the mechanical behaviors of granular materials.
      PubDate: 2017-06-01
      DOI: 10.1007/s11440-017-0530-8
      Issue No: Vol. 12, No. 3 (2017)
       
  • Validation of discrete element method by simulating a 2D assembly of
           randomly packed elliptical rods
    • Authors: Zhaofeng Li; Yu-Hsing Wang; Xia Li; Quan Yuan
      Pages: 541 - 557
      Abstract: Abstract This paper aims at establishing the predictive capability of the discrete element method (DEM) by validating the simulated responses of granular systems against experimental observations at both the macroscale and the microscale. A previously published biaxial shearing test on a 2D assembly of randomly packed elliptical rods was chosen as the benchmark test. In carrying out the corresponding DEM simulations herein, the contact model was derived and then validated using finite element analysis; the associated parameters were calibrated experimentally. The flexible (membrane) boundary was modeled by a bonded-particle string with experimentally calibrated parameters. An iteration procedure was implemented to replicate the initial packing and also to satisfy the boundary conditions in the experiment. Overall, the DEM simulation is found effective in reproducing the stress–strain–volumetric response, the statistical observation on the fabric anisotropy and the strain localization. Furthermore, the closer the numerical packing is to the experimental one, the closer the response is reproduced, demonstrating the significance of the initial packing reconstruction. Still, there are some minor differences between the experiment and simulation, reflecting the limitations associated with the particle number and the measurement resolution used in the experiment when reproducing the initial packing.
      PubDate: 2017-06-01
      DOI: 10.1007/s11440-017-0542-4
      Issue No: Vol. 12, No. 3 (2017)
       
  • Quantitative analysis of piping erosion micro-mechanisms with coupled CFD
           and DEM method
    • Authors: Hui Tao; Junliang Tao
      Pages: 573 - 592
      Abstract: Abstract Piping, as one of the critical patterns of internal erosion, has been reported as a major cause for failures of embankment dams and levees. The fundamental mechanism of piping was traditionally investigated through experimental trials and simplified theoretical methods in macroscale. Nevertheless, the initiation and progressive evolution of piping is a microscale phenomenon in its essence. The current understanding of the micro-mechanism of piping erosion is limited due to a lack of quantitative analysis and visualized evidence. And in fact, seepage flows can affect the soil fabrics and the development of contact forces between particles. But how these fabrics and contact forces evolve under a critical hydraulic gradient is still not fully understood. In this paper, the detailed process of piping erosion is investigated by using a coupled computational fluid dynamics and discrete element method (CFD–DEM) approach. The treatment of soil–flow interactions in CFD–DEM is explained by exchanging the momentum between the two phases. During the simulation, the piping erosion process is initiated by incrementally ascending differential water head across the soil samples. The three main stages of piping erosion (initial movement, continuation of erosion and total heave) can be identified from monitoring the particle velocity and positions. In addition, the evolution of contact force, hydraulic force, coordination number and void fraction is inspected to provide insight into the micro-mechanism of piping erosion. Two cases are simulated, one with a uniform particle size and a relatively uniform porosity distribution and the other with specific particle size and porosity distributions. An interesting finding from this study is that piping does not always initiate from the free surface and the evolution of piping depends heavily on the particle size and porosity distribution.
      PubDate: 2017-06-01
      DOI: 10.1007/s11440-016-0516-y
      Issue No: Vol. 12, No. 3 (2017)
       
  • Combined spheropolyhedral discrete element (DE)–finite element (FE)
           computational modeling of vertical plate loading on cohesionless soil
    • Authors: Christopher T. Senseney; Zheng Duan; Boning Zhang; Richard A. Regueiro
      Pages: 593 - 603
      Abstract: Abstract This paper presents a combined spheropolyhedral discrete element (DE)–finite element (FE) computational approach to simulating vertical plate loading on cohesionless soils such as gravels. The gravel particles are modeled as discrete elements, and the plate is modeled as a deformable FE continuum. The simulations provide a meaningful step toward better understanding how deformable bodies transmit loads to granular materials. The DE–FE contact algorithm is verified through comparison with an analytical solution for impact between two symmetric bars. A parametric study is conducted to ensure boundary effects are not significantly influencing the simulations. Numerical simulations are compared to experimental test results of lightweight deflectometer loading on a gravel base course with satisfactory agreement. Future developments of the approach intend to simulate wheel loading of military aircraft on unsurfaced airfields.
      PubDate: 2017-06-01
      DOI: 10.1007/s11440-016-0519-8
      Issue No: Vol. 12, No. 3 (2017)
       
  • Particle shape effect on thermal conductivity and shear wave velocity in
           sands
    • Authors: Changho Lee; Hyoung Suk Suh; Boyeong Yoon; Tae Sup Yun
      Pages: 615 - 625
      Abstract: Abstract This study presents the correlations between quantified shape parameters and geotechnical properties for nine sand specimens. Four shape parameters, sphericity, convexity, elongation and slenderness, were quantified with two-dimensional microscopic images with the aid of image processing techniques. An instrumented oedometer cell is used to measure compressibility, thermal conductivity and shear wave velocity during loading, unloading and reloading stages. As the particle shape inherently determines the initial loose packing condition, initial void ratio and shape parameters are well correlated with compressibility. The applied stress in soils increases the interparticle contact area and contact quality; round particles tend to achieve higher thermal conductivity and shear wave velocity during stress-induced volume change. Multiple linear regression is implemented to capture the relative contributions of involved variables, revealing that the thermal evolution is governed by the initial packing density and particle shape. The experimental observations underscore the predominant effect that particle shape has on the geomechanical and physical properties upon stress-induced soil behavior.
      PubDate: 2017-06-01
      DOI: 10.1007/s11440-017-0524-6
      Issue No: Vol. 12, No. 3 (2017)
       
  • Centroid sliding pyramid method for removability and stability analysis of
           fractured hard rock
    • Authors: Wei Wu; Xiaoying Zhuang; Hehua Zhu; Xingen Liu; Guowei Ma
      Pages: 627 - 644
      Abstract: Abstract This paper proposes a new method using centroid sliding pyramid (CSP) to identify the removability and stability of fractured hard rock in tunnel and slope engineering. The new method features two geometrical and topological improvements over the original key block method (KBM). Firstly, all the concave corners are considered as starting points of cutting process when a concave block is divided into a set of convex blocks in the original KBM. Only the concave corners formed by two joint planes are used for partitioning a concave block in the presented method and concave corners with free planes are excluded. Secondly, joint pyramid for removability computation in the original KBM is generated using all of the joint planes, while CSP is calculated only from the joint planes adjoining the free planes. The cone angle θ of CSP is the vectorial angle formed by the two candidate sliding surfaces of this CSP. Removability analysis of a block is transformed into calculating the cone angle of CSP. The geometrical relationship is simplified, and data size for removability computation is reduced compared with the original KBM. The provided method is implemented in a computer program and validated by examples of fractured rock slopes and tunnels.
      PubDate: 2017-06-01
      DOI: 10.1007/s11440-016-0510-4
      Issue No: Vol. 12, No. 3 (2017)
       
  • Fast shear behavior of granular materials in ring-shear tests and
           implications for rapid landslides
    • Authors: Yao Jiang; Gonghui Wang; Toshitaka Kamai
      Pages: 645 - 655
      Abstract: Abstract The high mobility of rapid landslides is one of the most important subjects of both theoretical and practical interest to engineers and scientists. The idea that ultralow resistance could explain the high mobility inspires researchers to examine the shear behavior of granular materials under a wide range of conditions, but the response of granular materials to fast loading rates is largely unknown. The motivation for this study was to examine several fundamental issues of particle properties and mechanical conditions on the fast shear behavior of granular materials. Two granular materials were studied in the oven-dried state and were sheared by employing a ring-shear apparatus. Results indicated that angular particles (silica sand) had higher shear strength parameters than spherical particles (glass beads). In addition, the dilative process was observed during shearing, which depended on normal stress and particle shape. A slightly negative shear-rate effect on shear strength was observed for both granular materials under a certain range of shear rates. Furthermore, cumulative shear displacement had a significant effect on the degree of particle crushing. Fast ring-shear tests also revealed that shear rate had a slightly negative effect on particle crushing. Based on these experimental results, the possible applications of dynamic grain fragmentation theory to assess the high mobility of rapid landsliding phenomena were discussed. It was indicated that the magnitude and release rate of elastic strain energy generated by grain fragmentation played important roles on the dynamic process of landslide mobility.
      PubDate: 2017-06-01
      DOI: 10.1007/s11440-016-0508-y
      Issue No: Vol. 12, No. 3 (2017)
       
  • Dynamic instabilities under isotropic drained compression of idealized
           granular materials
    • Authors: T. Doanh; N. Abdelmoula; L. Gribaa; T. T. T. Nguyên; S. Hans; C. Boutin; A. Le Bot
      Pages: 657 - 676
      Abstract: Abstract The compressibility behaviour of loose and contracting granular assemblies, normally consolidated and overconsolidated, under isotropic drained compression is investigated in this paper. Short cylindrical samples of water-saturated monodisperse glass beads, initially assembled in loose state by moist-tamping technique, are isotropically compressed in a classical axisymmetric triaxial machine. Very loose glass bead samples experience numerous unexpected events, sometimes cascading, under undetermined triggered effective isotropic stress in loading and in unloading, while the classical compressibility behaviour of granular material is recovered once these events ignored. Each event, resembling the stick–slip instability during shear in triaxial compression, is characterized by a transient dynamic phase I with very fast drop of effective isotropic stress \(\sigma ^{'}\) due to an excess pore pressure development at nearly constant volume and constant axial strain, followed by a quasi-static phase II with gradual increase in axial \(\varepsilon _\mathrm{a}\) (contraction) and volumetric \(\varepsilon _\mathrm{v}\) (compaction) strain, and a full progressive recovery of \(\sigma ^{'}\) to the previous level before event. A short-lived liquefaction with null \(\sigma ^{'}\) measured in the first phase I results in a local collapse state. Collapse events also happen on unsaturated moist and dry states. Rare events even occur during the unloading of subsequent isotropic compression cycles. The effects of triggered isotropic stress are discussed, the instability characteristics measured, the comparison with stick–slip instability made and the hypothesis of micro-structural instability with local collapse of contact networks and rapid micro-structural rearrangement argued.
      PubDate: 2017-06-01
      DOI: 10.1007/s11440-016-0514-0
      Issue No: Vol. 12, No. 3 (2017)
       
  • Modeling of unsaturated granular flows by a two-layer approach
    • Authors: Xiannan Meng; Yongqi Wang; Chun Wang; Jan-Thomas Fischer
      Pages: 677 - 701
      Abstract: Abstract Flows of partially saturated grain-fluid mixtures over complex curved topography are commonly observed in nature. However, comprehensive understanding of the physics behind them is to date out of reach. To investigate their dynamic process, a two-layer approach is proposed, in which the fluid-saturated granular layer is overlaid by the pure granular material. More specifically, the lower layer is described by a two-phase mixture theory of density preserving solid and fluid constituents. For the upper layer, the single-phase granular mass is treated as a frictional Coulomb-like continuum, and the dilation effect and the influence of the interstitial air are ignored. The capillarity effects and grains-size segregation are not considered in both the layers. The lower and upper layers interact at an interface which is a material surface for the fluid phase, but across which the mass exchange for the granular phase may take place. The granular mass exchange across the layer interface is parameterized by an entrainment type postulate. In addition, the classical jump conditions are employed to connect both layers at the interface dynamically. Furthermore, we perform the depth-averaged technique for the saturated grain-fluid mixture lower layer and the pure granular upper layer, respectively, to simplify the governing equations established. It is demonstrated that the resulting model equations can be reduced to most of the existing single-layer pure granular flow models and saturated two-phase single-layer debris flow models. Numerical solutions demonstrate that the present two-layer model can describe flows of partially saturated grain-fluid mixtures and the transition process of a saturated grain-fluid mixture into an under-saturated state.
      PubDate: 2017-06-01
      DOI: 10.1007/s11440-016-0509-x
      Issue No: Vol. 12, No. 3 (2017)
       
  • A numerical exercise for the definition under undrained conditions of the
           deep tunnel front characteristic curve
    • Authors: Claudio di Prisco; Luca Flessati; Gabriele Frigerio; Pietro Lunardi
      Abstract: In spite of the increasing diffusion of tunnel boring machines, conventional tunnelling is still largely employed in the excavation of both deep and shallow tunnels characterized by a particularly irregular tracing. Under difficult ground conditions, in conventional tunnelling, the front is frequently reinforced by using fibreglass tubes partially removed during the excavation. This technique is expensive, time-consuming and its design is based on either empirical or very simplified theoretical formulas. Thus, the ultimate objective of the research developed by the authors is to introduce a more sophisticated design approach for this front reinforcement technique. A first step in this direction is this numerical study, in which the mechanical response of deep tunnel faces under undrained conditions is analysed by employing the front characteristic curve: a useful tool largely employed in the literature in analogy with what done for the cavity. The main result of this paper is the “Front Mother Characteristic” curve, obtained by introducing appropriate non-dimensional variables, allowing the designer, once both the system geometry and the soil mechanical properties are assigned, to assess the displacements of tunnel fronts without performing any numerical analysis.
      PubDate: 2017-05-24
      DOI: 10.1007/s11440-017-0564-y
       
  • Multiscale modeling and analysis of compaction bands in high-porosity
           sandstones
    • Authors: Huanran Wu; Ning Guo; Jidong Zhao
      Abstract: We present a multiscale investigation on the initiation and development of compaction bands in high-porosity sandstones based on an innovative hierarchical multiscale approach. This approach couples the finite element method and the discrete element method (DEM) to offer direct, rigorous linking of the microscopic origins and mechanisms with complex macroscopic phenomena observed in granular rocks such as strain localization and failure. To simulate compaction band in granular cementitious sandstone, we adopt a bonded contact model with normal and tangential interparticle cohesions in the DEM and propose a dual-porosity structure consisting of macro-pores and interstitial voids for the representative volume element to mimic the typical meso-structure of high-porosity sandstones. In the absence of particle crushing, our multiscale analyses identify debonding and pore collapses as two major contributors to the formation of compaction bands. The critical pressures predicted by our simulations, corresponding to surges of debonding and pore collapse events, agree well with the estimations from field data. The occurrence patterns of compaction band are found closely related to specimen heterogeneity, porosity and confining pressure. Other deformation band patterns, including shear-enhanced compaction bands and compactive shear bands, were also observed under relatively low confining pressure conditions with a rough threshold at \(0.55P^{*}\) ( \(P^{*}\) is the critical pressure) on the failure envelop. Key microscopic characteristics attributable to the occurrence of these various deformation patterns, including fabric anisotropy, particle rotation, debonding and pore collapse, are examined. Shear-enhanced compaction bands and pure compaction bands bear many similarities in terms of these microscopic characteristics, whereas both differ substantially from compactive shear bands.
      PubDate: 2017-05-24
      DOI: 10.1007/s11440-017-0560-2
       
  • Deformation mechanism of strain localization in 2D numerical interface
           tests
    • Authors: Huaxiang Zhu; Wan-Huan Zhou; Zhen-Yu Yin
      Abstract: Abstract Heterogeneity arises in soil subjected to interface shearing, with the strain gradually localizing into a band area. How the strain localization accumulates and develops to form the structure is crucial in explaining some significant constitutive behaviors of the soil–structural interface during shearing, for example, stress hardening, softening, and shear-dilatancy. Using DEM simulation, interface shear tests with a periodic boundary condition are performed to investigate the strain localization process in densely and loosely packed granular soils. Based on the velocity field given by grains’ translational and rotational velocities, several kinematic quantities are analyzed during the loading history to demonstrate the evolution of strain localization. Results suggest that tiny concentrations in the shear deformation have already been observed in the very early stage of the shear test. The degree of the strain localization, quantified by a proposed new indicator, α, steadily ascends during the stress-hardening regime, dramatically jumps prior to the stress peak, and stabilizes at the stress steady state. Loose specimen does not develop a steady pattern at the large strain, as the deformation pattern transforms between localized and diffused failure modes. During the stress steady state of both specimens, remarkable correlations are observed between α and the shear stress, as well as between α and the volumetric strain rate.
      PubDate: 2017-05-19
      DOI: 10.1007/s11440-017-0561-1
       
  • Pressuremeter test parameters of a compacted illitic soil under thermal
           cycling
    • Authors: H. Eslami; S. Rosin-Paumier; A. Abdallah; F. Masrouri
      Abstract: Abstract The incorporation of heat exchangers in geostructures changes the temperature of the adjacent soil, raising important issues concerning the effect of temperature variations on hydro-mechanical soil behaviour. The objective of this paper is to improve the understanding and quantification of the impact of temperature variation on the bearing capacity of thermo-active piles. Currently, the design of deep foundations is based on the results of in situ penetrometer or pressuremeter tests. However, there are no published data on the effect of temperature on in situ soil parameters, preventing the specific assessment of the behaviour of thermo-active piles. In this study, an experimental device is developed to perform mini-pressuremeter tests under controlled laboratory conditions. Mini-pressuremeter tests are performed on an illitic soil in a thermo-regulated metre-scale container subjected to temperatures from 1 to 40 °C. The results reveal a slight decrease in the pressuremeter modulus (E p) and a significant decrease in the creep pressure (p f) and limit pressure (p l) with increasing temperature. The results also reveal the reversibility of this effect during a heating–cooling cycle throughout the investigated temperature range, whereas the effect of a cooling–heating cycle was only partially reversible. In the case of several thermal cycles, the effect of the first cycle on the soil parameters is decisive.
      PubDate: 2017-05-19
      DOI: 10.1007/s11440-017-0552-2
       
  • Investigation of the change in soil fabric during cone penetration in silt
           using 2D measurements
    • Authors: Priscilla Paniagua; Joana Fonseca; Anders Gylland; Steinar Nordal
      Abstract: Abstract Interpretation of CPTU testing in silt is non-trivial because of the partially drained conditions that are likely to occur during penetration. A better understanding of the pore pressure generation/dissipation is needed in order to obtain reliable design parameters. Following a previous study using X-ray computed tomography (micro-CT) with volumetric digital image correlation (3D-DIC) that clearly showed the formation of distinct dilation and compression areas around the cone; the present work takes a closer look at those areas in order to link volumetric behavior to changes in soil fabric. High-resolution 2D backscattered electron images of polished thin sections prepared from frozen samples at the end of penetration are used. The images have a spatial resolution of 0.4 µm/pixel that allow a clear identification of grains and pore spaces. Image processing techniques are developed to quantify local porosity and obtain the statistical distribution of the particle orientation for the zones around the cone tip and shaft. It is shown that the formation of compaction regions is related to the ability of the grains to rearrange and align along a well-defined preferred orientation forming a more closed-fabric characterized by high anisotropy values, while zones of dilation are associated with a more open packing with grains randomly oriented and with large voids within. These observations suggested that for a saturated soil, water will move from a compressive zone to a neighboring dilative zone, creating a short drainage path. By shedding light on the link between soil fabric and drainage patterns, this study contributes toward a better understanding of the measured macro-response during CPTU tests on silt.
      PubDate: 2017-05-19
      DOI: 10.1007/s11440-017-0559-8
       
  • Influence of gravel segregation on gluing solution solidification in a
           railway ballast
    • Authors: Chung Fang; Yusin Lee; Yung-Jung Lin; Li-Sin Lu; Po-Chen Chen
      Abstract: Abstract Influence of gravel segregation on gluing solution distribution in a realistic railway ballasts is investigated numerically. The rheological characteristics of the gluing solution are accounted for by using a coupled elasto-visco-plastic stress model with an asymptotic time increasing viscosity. The realistic railway ballast is accomplished by using the vertex identification technique, in which the regulations of the gravel composition in ballast practice are followed. Specifically, a uniformly distributed one and a segregated one induced by the difference in gravel size and gravel shape are generated. The rheological model of the gluing solution and twofold ballasts are incorporated into the finite element code of ANSYS \(^{\copyright }\) to study the flow characteristics and time-dependent solidification of the gluing solution. Relatively concrete vertical and lateral gravel–gravel adhesion in twofold ballasts can be generated by using denser network arrangement of the gluing solution; the vertical penetration in the uniform ballast is slightly deeper than that in the segregated ballast, while a slightly reverse tendency in the lateral extension near the upper and central parts appears. However, the difference in the solidified gluing solution distributions in both ballasts is essentially insignificant, indicating that the influence of the gravel segregation needs not necessary to be taken into account in gluing practice when percolation is not taken into account.
      PubDate: 2017-04-05
      DOI: 10.1007/s11440-017-0544-2
       
  • Three-dimensional DEM analysis of single geogrid-encased stone columns
           under unconfined compression: a parametric study
    • Authors: Meixiang Gu; Jie Han; Minghua Zhao
      Abstract: Abstract Three-dimensional discrete element method (DEM) was employed in this study to analyze the behavior of single geogrid-encased stone columns under unconfined compression. Four important parameters were investigated to understand and evaluate their effects on the behavior of the encased columns by seven DEM models. The biaxial geogrid used as an encasement material for stone columns was simulated using parallel-bonded particles, and the aggregate in the stone column was simulated using graded particles. Both the macroscopic responses (e.g., vertical pressure–strain curves) and the microscopic interactions (e.g., contact force, coordination number, and sliding fraction) of the columns under unconfined compression were analyzed and are presented in this paper. The numerical results show that the geogrid encasement with high tensile stiffness could provide high confining stresses and then effectively increased the bearing capacity of the column. The short column yielded quickly even though its column modulus at a small deformation was relatively high. The modulus of the column slightly decreased with an increase in the column diameter due to high circumferential strains mobilized in the geogrid encasement. The column with large aggregate was stiffer and deformed less than the column with small aggregate. Selecting aggregate with a size larger than the geogrid aperture size was an effective way to achieve better interlocking between the aggregate and the geogrid and to minimize mass loss for the geogrid-encased stone column under loading. Due to limited deformation allowed by the geogrid encasement, a coefficient of radial stress equal to half of the coefficient of passive earth pressure was suggested to estimate the ultimate bearing capacity of the geosynthetic-encased stone column.
      PubDate: 2017-04-04
      DOI: 10.1007/s11440-017-0547-z
       
 
 
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