| 摘要: |
| 为了研究孔隙填充型可燃冰沉积物在复杂应力状态下的力学特性,采用三维离散元法对孔隙填充型可燃冰沉积物试样进行在不同平均应力、不同中主应力系数下的真三轴压缩模拟试验,研究平均应力和中主应力系数对宏、细观力学性质的影响以及细观力学机制的演化与宏观力学特性的联系。结果表明:平均应力的取值主要影响可燃冰沉积物的峰值强度;大、中、小主应力以及大、中、小主应变受到中主应力系数的取值影响较大,其变化趋势与颗粒接触的强接触组构主值表现出良好的相似性;在三向应力不等的情况下,可燃冰沉积物的破坏强度符合Lade-Duncan准则;随着中主应力系数逐渐增大,XY平面上的法向接触力更倾向于朝着中主应力方向发展。 |
| 关键词: 可燃冰沉积物 真三轴压缩试验 离散单元法 平均应力 中主应力系数 宏细观力学性质 |
| DOI：10.3969/j.issn.1673-5005.2020.01.015 |
| 分类号::TU 411 |
| 文献标识码:A |
| 基金项目:国家重点研发计划项目 (2017YFC0307604) |
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| Discrete element simulation of true triaxial tests on macro and meso mechanical properties of combustible ice sediments |
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ZHOU Bo, WANG Hongqian, WANG Hui, ZHOU Shichen, XUE Shifeng
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(College of Pipeline and Civil Engineering in China University of Petroleum(East China), Qingdao 266580, China)
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| Abstract: |
| In order to study the mechanical properties of pore-filled combustible ice sediments under complex stress conditions, a series of true triaxial tests were carried out using the three-dimensional discrete element method with different mean effective stresses and different intermediate stress ratios. The effects of mean effective stress and the intermediate stress ratio on the macroscopic mechanical properties, and the relationship between the evolution of the mesoscopic mechanical mechanism and the macroscopic mechanical properties of combustible ice sediments were studied. The results show that the value of mean effective stress mainly affects the peak strength of combustible ice sediments. There is a great similarity between the variations in principal stresses (i.e. major, intermediate and minor principal stress), principal strains (i.e. major, intermediate and minor principal strains) and the stronger contact fabric tensor of the particles, and the principal stresses and principal strains are strongly effected by the intermediate stress ratios. The strength under complex stress conditions of combustible ice sediments obeys the Lade-Duncan failure criterion. With the increase of the intermediate stress ratio, the normal contact force in the XY plane tends to develop toward the direction of the intermediate principal stress. |
| Key words: combustible ice sediments true triaxial tests discrete element method mean effective stress intermediate stress ratio macro and meso mechanical properties |
