Numerical simulation of true triaxial tests on mechanical behaviors of rockfill based on stochastic granule model
ZHOU Wei 1, 2 , LIU Dong1, 3 , MA Gang 1, 2 , CHANG Xiao-lin 1, 2
1. Sta te Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan 430072, China; 2. Key Laboratory of Rock Mechanics in Hydraulic Structural EngineeringWuhan University, Ministry of Education , Wuhan 430072, China; 3. Hydrochina Zhongnan Engineering Corporation, Changsha 410014, China
Abstract:The three-dimensional deformable discrete element method is employed to study the strength and deformation characteristics of rockfill under three-dimensional unequal stress states by means of true triaxial numerical tests. In addition, the six-rigid-plate loading and the constant value of the intermediate principal stress ratio loading paths are adopted. The simulated results show that the true triaxial numerical tests can preferably reflect the stress and deformation of rockfill under the three-dimensional unequal stress states, and the numerical results are the same as the test ones. The stress ratio parameters significantly affect the stress intensity of rockfill under the three-dimensional stress state and the three-dimensional strain also changes with the increase of the ratio parameters. To be more specifical, when the intermediate principal stress ratio parameter b increases from 0 to 1, the second principal strain direction changes from compression to expansion while the third principal strain direction has always been in the state of compression, and the the internal friction angle of rockfill increases with the increase of b, which basically conforms to the Lade-Duncan failure criterion. In the mesoscopic level, the higher the confining pressure is, the larger the value of b and coordination number of particles are. In the loading process, the anisotropy degree of contact normal orientation and contact normal force are strengthened, the main direction of contact force turns to the loading direction, the anisotropic coefficient evolution curve is similar to the stength curve, in other words, the strength of the rockfill samlpes has some relationship with the normal contact.
周伟, 刘东, 马刚, *, 常晓林. 基于随机散粒体模型的堆石体真三轴数值试验研究[J]. 岩土工程学报, 2012, 34(4): 748-755.
ZHOU Wei , , LIU Dong , MA Gang , , CHANG Xiao-lin , . Numerical simulation of true triaxial tests on mechanical behaviors of rockfill based on stochastic granule model. Chinese J. Geot. Eng., 2012, 34(4): 748-755.
[1] 朱思哲 , 刘 虔 , 包承纲 . 三轴试验原理与应用技术 [M]. 中国电力出版社 , 2003. (ZHU Si-zhe, LIU Qian, BAO Cheng-gang. Triaxial test principle and application technology[M]. Beijing: China Electric Power Press, 2003. (in Chinese)) [2] 李广信 . 土的三维本构关系的探讨与模型难 [D]. 北京 : 清华大学水利水电工程系 , 1985. (LI Guang-xin. A study of three-dimensional constitutive relationship of soils and an examination of various models[D]. Beijing: Hydraulic Engineering Department, Tsinghua University, 1985. (in Chinese)) [3] 朱俊高 , 卢海华 , 殷宗泽 . 土体侧向变形性状的真三轴试验研究 [J]. 河海大学学报 , 1995, 23 (6): 28 – 33. (ZHU Jun-gao, LU Hai-hua, YIN Zong-ze. Lateral deformation of soil in true triaxial test[J]. Journal of Hohai University, 1995, 23 (6): 28 – 33. (in Chinese)) [4] 徐志伟 , 殷宗泽 . 粉砂侧向变形特性的真三轴试验研究 [J]. 岩石力学与工程学报 , 2000, 19 (5) : 626 – 629 . (XU Zhi-wei, YIN Zong-ze. Study on deformation characteristic of silt by true triaxial test[J]. Chinese Journal of Rock Mechanics and Engineering, 2000, 19 (5) : 626 – 629 . (in Chinese)) [5] SHI Wei-cheng, ZHU Jun-gao. Strength and deformation beformation behaviour of coarse-grained soil by true triaxial tests[J]. J Cent South Univ Technol, 2010, 17 : 1095 – 1102. [6] 施维成 , 朱俊高 , 刘汉龙 . 粗粒土应力诱导各向异性真三轴试验研究 [J]. 岩土工程学报 , 2008, 30 (10): 810 – 814 . (SHI Wei-cheng, ZHU Jun-gao, LIU Han-long. Stress induced anisotropic behaviour of coarse-grained soil by true triaxial tests[J]. Chinese Journal of Geotechnical Engineering, 2008, 30 (10): 810 – 814 . (in Chinese)) [7] KO H, SCOTT R F. Deformation sand and failure[J]. ASCE, 1968, 94 (4): 883 – 898. [8] LADE P V, DUNCAN J M. Cubical triaxial tests on cohesionless soil[J]. Journal of the Soil Mechanics and Foundations Division, 1973, 99 (10): 793 – 812. [9] LADE P V. Assessment of test data for selection of 3-D failure criterion for sand[J]. International Journal for Numerical and Analytical Methods in Geomechanics, 2006, 30 : 307 – 333. [10] LADE P V, DUNCAN J M..Elastoplastic stress-strain theory for cohesionless soil[J]. Journal of Geotech Engng Div, ASCE, 1975, 101 : 1037 – 1053. [11] NAKAI T, MATSUOKA H. Shear behavior of sand and clay under three-Dimensional stress condition[J]. Soils and Foundations, Japanese Siciety of siol Mechanics and Foundation Engineering, 1983, 23 : 27 – 42. [12] MATSUOKA h, NAKAI T. Stress-deformation and strength characteristics of soil under three different principal stresses[C]// Proc Japan Soc Civil Engrs, 1974, 232: 59 – 70. [13] YIN Jian-hua, CHENG Chun-man, KUMRUZZAMAN M D. New mixed boundary, true triaxial loading device for testing three-dimensional stress-strain-strength behaviour of geoma- terials[J]. Can Geotech, 2010, 47 : 1 – 15. [14] CALLISTO L, GAJO A, WOOD Muir. Simulation of triaxial and true triaxial tests on natural and reconstituted Pisa clay [J]. Géotechnique, 2002, 52 : 649 – 666. [15] THORNTON C. Numerical simulations of deviatoric shear deformation of granular medial [J]. Géotechnique, 2000, 50 : 43 – 53. [16] BELHEINE N, PLASSIARD J P. Numerical simulation of drained triaxial test using 3D discrete element modeling[J]. Computers and Geotechnics, 2009, 36 : 320 – 331. [17] TANG-TAT N G. Behavior of gravity deposited granular material under different stress paths[J]. Canadian Geotechnical Journal, 2005, 42 : 1644 – 1655. [18] TANG-TAT N G. Macro-and micro-behavior of granular materials under different sample preparation methods and stress paths[J]. International Journal of Solids and Structures, 2004, 41 (21): 5871 – 5884. [19] 周 伟 , 常晓林 , 周创兵 , 等 . 堆石体应力变形细观模拟的随机散粒体不连续变形模型及其应用 [J]. 岩石力学与工程学报 , 2009, 28 (3): 491 – 499. (ZHOU Wei, CHANG Xiao-lin, ZHOU Chuang-bing, et al. Stochastic granule discontinuous deformation model of rockfill and its application[J]. Chinese Journal of Rock Mechanics and Engineering, 2009, 28 (3): 491 – 4995. (in Chinese)) [20] CHANG X L, ZHOU W. A contact model on basis of the augmented Lagrange method and engineering application[J]. Chinese Journal of Rock Mechanics and Engineering, 2004, 23 (9): 1568 – 1572. [21] 马 刚 , 周 伟 , 常晓林 , 等 . 锚杆加固散粒体的作用机制研究 [J]. 岩石力学与工程学报 , 2010, 29 (8): 1577 – 1584. (MA Gang, ZHOU Wei, CHANG Xiao-lin, et al. Study of anchorage mechanism of granular mixture[J]. Chinese Journal of Rock Mechanics and Engineering, 2010, 29 (8): 1577 – 1584. (in Chinese))