ارزیابی تأثیر شکل مصالح دانه‌ای بر رفتار تراکم‌پذیری تک‌ محوری به روش تحلیلی و آزمایشگاهی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه ژئوتکنیک، دانشکده مهندسی عمران و مرکز تحقیقات زلزله دانشگاه صنعتی سهند، تبریز، ایران

2 دانشکده مهندسی عمران و مرکز تحقیقات زلزله دانشگاه صنعتی سهند، تبریز، ایران

چکیده

مصالح دانه‌ای که امروزه در بسیاری از پروژه‌های مهندسی همچون سدهای سنگریزه‌ای و خطوط راه‌آهن مورد استفاده قرار می‌گیرند، دارای تنوع بسیاری در شکل می‌باشند. این تنوع شکلی در محدوده بسیار تیزگوشه تا کاملاً گردگوشه قرار می‌گیرد. شکل مصالح دانه‌ای بر روی خواص مکانیکی دانه از جمله مقاومت شکست و زاویه اصطکاک داخلی تأثیر می‌گذارد. در نتیجه رفتار مکانیکی توده مصالح دانه‌ای وابسته به شکل دانه‌ها می‌باشد. به منظور بررسی تأثیر این خصوصیت، انواع مختلفی از دانه‌ها در شکل‌های کره، استوانه، مکعب و هرم که در برگیرنده طیف وسیعی از شکل مصالح دانه‌ای طبیعی می‌‌باشند، به صورت مصنوعی، در محدوده اندازه 1 الی 2/5 سانتی‌متر ساخته شدند. آزمایش‌های تراکم‌پذیری تک‌ محوری کوچک-مقیاس بر روی هر یک از شکل‌های مصالح دانه‌ای در شرایط یکسان شامل نسبت تخلخل اولیه و تنش حداکثر انجام گرفت و بعد از هر آزمایش، رفتار تنش-کرنش و مقدار شکست مصالح با استفاده از فاکتور شکست هاردین به دست آمدند. سپس نتایج حاصله، با استفاده از مدل تحلیلی مک‌داول و همکاران که بر مبنای اصل پایستگی انرژی می‌باشد، ارزیابی گردید. این مدل دارای 7 پارامتر می‌باشد که به نسبت تخلخل اولیه دانه‌ها، جنس، شکل، اندازه و مقاومت دانه‌ها در برابر شکست بستگی دارند. ارزیابی و مقایسه نتایج، حاکی از قابلیت این مدل تحلیلی در پیش‌بینی رفتار تراکم‌پذیری مصالح دانه‌ای هرمی ‌شکل می‌باشد. به طوری که با تیزگوشه‌تر شدن مصالح، تراکم‌پذیری و شکست مصالح افزایش می‌یابند. همچنین با افزایش انرژی سطحی شکست مصالح، تأثیر شکل در تراکم‌پذیری دچار کاهش می‌گردد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Evaluation of the effect of shape of granular materials on uniaxial compressibility behavior by analytical and experimental methods

نویسندگان [English]

  • Vahid Gorbanpoor 1
  • Mehrdad EMAMI Tabrizi 2
  • Hassan Afshin 2
1 Civil Engineering Faculty, Sahand University of Technology
2 Civil Engineering Faculty, Sahand University of Technology, Tabriz
چکیده [English]

Granular materials used today in many engineering projects, such as rockfill dams and railways, have a wide variety of shapes. This shape variation ranges from very sharp to perfectly rounded. The shape of the aggregates affects the mechanical properties of the grain, including fracture strength and internal friction angle. As a result, the mechanical behavior of the mass of granular materials depends on the shape of the grains. In order to investigate the effect of this property, different types of grains in the shapes of spheres, cylinders, cubes and pyramids, which include a wide range of shapes of natural aggregates, were made artificially in size range of 1.5 to 2.0 cm. Small-scale uniaxial compressibility tests were performed on each of the grain shapes under the same conditions including initial porosity ratio and maximum stress and after each experiment, the stress-strain behavior and the amount of breakage were obtained using the Hardin breakage factor. Then, the results were evaluated using an analytical model proposed by McDowell et al. based on the law of conservation of energy. This model has 7 parameters that depend on the initial conditions of the grains, material, shape, size and fracture strength of the grains. Comparison and evaluation of the results indicates the ability of the analytical model to predict the compressibility behavior of pyramidal grains. As the grains become angular, the compressibility and breakage of the materials increase. Also, with increasing the fracture surface energy of the material, the effect of shape on compressibility decreases.

کلیدواژه‌ها [English]

  • Uniaxial compressibility
  • Shape effect
  • Weibull theory
  • Fractal theory
  • Grains
  1. [1] W. Zhou, L. Yang, G. Ma, X. Chang, Z. Lai, K. Xu, DEM analysis of the size effects on the behavior of crushable

    granular materials, Granul. Matter, 18(3) (2016) 64.

    [2] A. Gupta, Triaxial behaviour of rockfill materials, Electronic Journal of Geotechnical Engineering, 14 (2009).

    [3] X. Zhang, B.A. Baudet, T. Yao, The influence of particle shape and mineralogy on the particle strength, breakage and

    compressibility, International Journal of Geo-Engineering, 11(1) (2020) 1-10.

    [4] P.V. Lade, J.A. Yamamuro, P.A. Bopp, Significance of particle crushing in granular materials, Journal of Geotechnical

    Engineering, 122(4) (1996) 309-316.

    [5] Y. Wang, S. Shao, Z. Wang, Effect of particle breakage and shape on the mechanical behaviors of granular materials,

    Adv. Civil Eng., 2019 (2019) 7248427.

    [6] Y. Li, Effects of particle shape and size distribution on the shear strength behavior of composite soils, B. Eng. Geol.

    Environ., 72(3) (2013) 371-381.

    [7] K. Miura, K. Maeda, M. Furukawa, S. Toki, Mechanical characteristics of sands with different primary properties,

    Soils Found., 38(4) (1998) 159-172.

    [8] G.-C. Cho, J. Dodds, J.C. Santamarina, Particle shape effects on packing density, stiffness, and strength: natural and

    crushed sands, J. Geotech. Geoenviron., 132(5) (2006) 591-602.

    [9] N. Altuhafi Fatin, R. Coop Matthew, N. Georgiannou Vasiliki, Effect of particle shape on the mechanical behavior of

    natural sands, J. Geotech. Geoenviron., 142(12) (2016) 04016071.

    [10] X. Wu, Y. Cai, S. Xu, Y. Zhuang, Q. Wang, Z. Wang, Effects of size and shape on the crushing strength of coral

    sand particles under diametral compression test, B. Eng. Geol. Environ., 80(2) (2021) 1829-1839.

    [11] T. Zhang, C. Zhang, J. Zou, B. Wang, F. Song, W. Yang, DEM exploration of the effect of particle shape on particle

    breakage in granular assemblies, Comput. Geotech., 122 (2020) 103542.

    [12] M.B. Cil, C. Sohn, G. Buscarnera, DEM Modeling of Grain Size Effect in Brittle Granular Soils, Journal of

    Engineering Mechanics, 146(3) (2020) 04019138.

    [13] A.A. Mirghasemi, L. Rothenburg, E.L. Matyas, Influence of particle shape on engineering properties of assemblies

    of two-dimensional polygon-shaped particles, Géotechnique, 52(3) (2002) 209-217.

    [14] M. Lu, G.R. McDowell, The importance of modelling ballast particle shape in the discrete element method, Granul.

    Matter, 9(1) (2007) 69.

    [15] S. Abedi, A.A. Mirghasemi, Particle shape consideration in numerical simulation of assemblies of irregularly shaped

    particles, Particuology, 9(4) (2011) 387-397.

    [16] G.R. McDowell, M.D. Bolton, D. Robertson, The fractal crushing of granular materials, J. Mech. Phys. Solids, 44(12)

    (1996) 2079-2101.

    [17] Y. Xiao, Y. Sun, H. Liu, F. Yin, Critical state behaviors of a coarse granular soil under generalized stress conditions,

    Granul. Matter, 18(2) (2016) 17.

    [18] Y. Xiao, Y. Sun, K.F. Hanif, A particle-breakage critical state model for rockfill material, Sci. China Tech. Sci.,

    58(7) (2015) 1125-1136.

    [19] M. Liu, Y. Gao, H. Liu, An elastoplastic constitutive model for rockfills incorporating energy dissipation of nonlinear

    friction and particle breakage, International Journal for Numerical and Analytical Methods in Geomechanics, 38(9)

    (2014) 935-960.

    [20] A. Daouadji, P.-Y. Hicher, An enhanced constitutive model for crushable granular materials, International Journal

    for Numerical and Analytical Methods in Geomechanics, 34(6) (2010) 555-580.

    [21] D. Muir Wood, K. Maeda, Changing grading of soil: Effect on critical states, Acta Geotech., 3 (2008) 3-14.

    [22] C.S. Chang, P.Y. Hicher, An elasto-plastic model for granular materials with microstructural consideration, Int. J.

    Solids Struct., 42(14) (2005) 4258-4277.

    [23] W. Salim, B. Indraratna, A new elastoplastic constitutive model for coarse granular aggregates incorporating particle

    breakage, Can. Geotech. J., 41(4) (2004) 657-671.

    [24] M.-P. Luong, M. Emami, Characterization of mechanical damage in granite, Fracture and Strucrural Integrity, 8(27)

    (2014) 38-42.

    [25] J. Atkinson, The Mechanics of Soils and Foundations (2nd ed.), CRC Press, 2007.

    [26] J. Jaky, Pressure in silos, in:  2nd International Conference on Soil Mechanics and Foundation Engineering, 1948,

    1. 103–107.

    [27] J. Zhang, B. Zhang, Fractal pattern of particle crushing of granular geomaterials during one-dimensional

    compression, Adv. Civil Eng.,  (2018) 2153971.

    [28] D.L. Turcotte, Fractals and fragmentation, Journal of Geophysical Research: Solid Earth, 91(B2) (1986) 1921-1926.

    [29] G.R. McDowell, M.D. Bolton, On the micromechanics of crushable aggregates, Géotechnique, 48(5) (1998) 667-

    679.

    [30] I. Einav, Breakage mechanics—Part I: Theory, J. Mech. Phys. Solids, 55(6) (2007) 1274-1297.

    [31] M.R. Coop, K.K. Sorensen, T. Bodas Freitas, G. Georgoutsos, Particle breakage during shearing of a carbonate sand,

    Géotechnique, 54(3) (2004) 157-163.

    [32] W. Weibull, A statistical theory of the strength of materials, Generalstabens litografiska anstalts förlag, Stockholm,

    1939.

    [33] Y. Nakata, Y. Kato, M. Hyodo, A.F.L. Hyde, H. Murata, One-dimensional compression behaviour of uniformly

    graded sand related to single particle crushing strength, Soils Found., 41(2) (2001) 39-51.

    [34] G. Mesri, B. Vardhanabhuti, Compression of granular materials, Can. Geotech. J., 46(4) (2009) 369-392.

    [35] G.R. McDowell, On the yielding and plastic compression of sand, Soils Found., 42(1) (2002) 139-145.

    [36] R.D. Holtz, W.D. Kovacs, An Introduction To Geotechnical Engineering, Prentice-Hall, New Jersey, 1981.

    [37] A. Sharma, D. Penumadu, Role of particle shape in determining tensile strength and energy release in diametrical

    compression of natural silica grains, Soils Found., 60(5) (2020) 1299-1311.

    [38] N. Stark, A.E. Hay, R. Cheel, C.B. Lake, The impact of particle shape on the angle of internal friction and the

    implications for sediment dynamics at a steep, mixed sand–gravel beach, Earth Surf. Dynam., 2(2) (2014) 469-480.

    [39] ASTM-D7012-14e1, Standard Test Methods for Compressive Strength and Elastic Moduli of Intact Rock Core

    Specimens under Varying States of Stress and Temperatures, in, ASTM International, West Conshohocken, PA, 2014.

    [40] ASTM-D3967-16, Standard Test Method for Splitting Tensile Strength of Intact Rock Core Specimens, in, ASTM

    International, West Conshohocken, PA, 2016.

    [41] Z.T. Bieniawski, Engineering Rock Mass Classifications: A Complete Manual for Engineers and Geologists in

    Mining, Civil, and Petroleum Engineering, Wiley, 1989.

    [42] ASTM-D2845-08, Standard Test Method for Laboratory Determination of Pulse Velocities and Ultrasonic Elastic

    Constants of Rock, in, ASTM International, West Conshohocken, PA, 2008.

    [43] V. Hucka, B. Das, Brittleness determination of rocks by different methods, Int. J. Rock Mech. Min., 11(10) (1974)

    389-392.

    [44] P.J. Barrett, The shape of rock particles, a critical review, Sedimentology, 27(3) (1980) 291-303.

    [45] M.C. Powers, A new roundness scale for sedimentary particles, Journal of Sedimentary Research, 23(2) (1953) 117-

    119.

    [46] ASTM-D2488, Standard practice for description and identification of soils, in, ASTM International, West

    Conshohocken, PA, 2017.

    [47] B. Indraratna, D. Ionescu, H.D. Christie, Shear behavior of railway ballast based on large-scale triaxial tests, J.

    Geotech. Geoenviron., 124(5) (1998) 439-449.

    [48] ASTM-D2435, Standard test methods for one-dimensional consolidation properties of soils using incremental

    loading, in, ASTM International, West Conshohocken, PA, 2020.

    [49] C. Sammis, G. King, R. Biegel, The kinematics of gouge deformation, Pure Appl. Geophys., 125(5) (1987) 777-812.

    [50] ASTM-C1444-00, Standard Test Method for Measuring the Angle of Repose of Free-Flowing Mold Powders, in,

    ASTM International, West Conshohocken, PA, 2000.

    [51] K.L. Lee, I. Farhoomand, Compressibility and crushing of granular soil In anisotropic triaxial compression, Can.

    Geotech. J., 4(1) (1967) 68-86.

    [52] R. Marsal, Large scale testing of rockfill materials  Journal of the Soil Mechanics and Foundations Division, 93(2)

    (1967) 27-43.

    [53] B.O. Hardin, Crushing of soil particles, Journal of Geotechnical Engineering, 111(10) (1985) 1177-1192.