| 珊瑚砂高压力下一维蠕变分形破碎及颗粒形状分析 |
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| 引用本文： | 张小燕,蔡燕燕,王振波,江芸倩.珊瑚砂高压力下一维蠕变分形破碎及颗粒形状分析[J].岩土力学,2018,39(5):1573-1580. |
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| 作者姓名： | 张小燕 蔡燕燕 王振波 江芸倩 |
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| 作者单位： | 1. 中国矿业大学（北京） 力学与建筑工程学院，北京 100083； 2. 中国矿业大学 深部岩土力学与地下工程国家重点实验室，江苏 徐州 221008；3. 华侨大学 岩土工程研究所，福建 厦门 361021 |
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| 基金项目： | 国家自然科学基金项目（No. 51774147）；中国矿业大学深部岩土力学与地下工程国家重点实验室开放基金（No. SKLGDUEK1701）；福建省自然科学基金项目（No. 2017J01094）；中央高校基本科研业务费（No. 2017QL04）。 |
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| 摘 要： | 珊瑚砂是一种含钙极高的海洋生物成因材料，具有高棱角性、形状不规则、易破碎等特点。通过珊瑚砂的高压一维蠕变试验，研究颗粒破碎引起颗粒分布曲线和形状因子的演化规律。借助于高速动态图像的激光粒度粒形仪器，从统计学的角度分析试验前后颗粒形状随压力演化的关系，发现颗粒的形状因子，如长宽比、球形度和凹凸度等，随压力增加而逐渐增加。不同粒径的颗粒形状因子均向一个窄幅范围趋近，说明颗粒破碎具有无尺度性和自相似性的分形特性，分形维数随压力增加而逐渐增大，且趋近分形破碎极限。采用Hardin和Einav的方法计算相对破碎量，发现在两种计算方法下相对破碎量与压力呈幂函数关系，且幂指数相同。相对破碎量随时间增加的现象并不明显，说明在高压力下颗粒破碎主要为压缩破碎，且颗粒细化滑移填充孔隙引起的变形是造成蠕变的主要原因。
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| 关 键 词： | 珊瑚砂 分形 颗粒形状 蠕变 颗粒破碎 |
| 收稿时间： | 2017-04-21 |
Fractal breakage and particle shape analysis for coral sand under high-pressure and one-dimensional creep conditions |
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| ZHANG Xiao-yan,CAI Yan-yan,WANG Zhen-bo,JIANG Yun-qian.Fractal breakage and particle shape analysis for coral sand under high-pressure and one-dimensional creep conditions[J].Rock and Soil Mechanics,2018,39(5):1573-1580. |
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| Authors: | ZHANG Xiao-yan CAI Yan-yan WANG Zhen-bo JIANG Yun-qian |
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| Institution: | 1. School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing 100083, China; 2. State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221008, China; 3. Institute of Geotechnical Engineering, Huaqiao University, Xiamen, Fujian 361021, China) |
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| Abstract: | Coral sand is a type of marine biogenic granular material with extremely high calcium content. From the microscopic viewpoint, coral sand grains are characterized as highly angular, irregular in shapes and crushable. One-dimensional creep tests were conducted on coral sand under very high pressure to investigate the evolution of particle size distribution and change of particle shapes caused by particle breakage. Benefited from particle size analysis and shape evaluation with high speed dynamic image analysis apparatus, the evolution of particle shape along with stress was analyzed statistically, and shape factors including aspect ratio, sphericity and convexity increase with increasing pressure. Shape factors for particles with different sizes tend to reach a same value, which illustrated that the morphology of particle after breakage is scale independent and self-similar in this wide range of sizes. This paper analyzed the fractal feature after particle breakage, and found that the fractal dimension increases with increasing vertical stress, and eventually reaches the fractal ultimate breakage (D=2.5). This paper calculated the relative breakage by using Hardin’s and Einav’s methods, and found that relative breakage is increasing along with increasing pressure. The relative breakage is an exponent function with the pressure, which could be used to predict the relative breakage if the material and pressure are known. The increasing tendency with time is not obvious, because particle breakage is majorly caused by compression instead of creep. |
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| Keywords: | coral sand fractal particle shape creep particle breakage |
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