| 冻融循环作用下富平黄土微观结构几何类型变化研究 |
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| 引用本文： | 付翔宇,张泽,杨成松,恽晴飞,明姣.冻融循环作用下富平黄土微观结构几何类型变化研究[J].冰川冻土,2021,43(2):484-496. |
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| 作者姓名： | 付翔宇 张泽 杨成松 恽晴飞 明姣 |
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| 作者单位： | 兰州大学土木工程与力学学院,甘肃兰州730000;中国科学院西北生态环境资源研究院冻土工程国家重点实验室,甘肃兰州730000;中国科学院西北生态环境资源研究院冻土工程国家重点实验室,甘肃兰州730000;东北林业大学寒区科学与工程研究院/土木工程学院,黑龙江哈尔滨150040;中国科学院西北生态环境资源研究院冻土工程国家重点实验室,甘肃兰州730000 |
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| 基金项目： | 国家自然科学基金项目(41771078);冻土工程国家重点实验室自主研究项目(SKLFSE-ZT-19) |
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| 摘 要： | 冻融循环作用可通过影响寒区土体结构致使基础设施发生破坏，而导致工程失稳宏观现象的根源来自于冻融作用改变了土体的微观结构。为探索冻融作用下土体微观结构变化规律，将富平黄土作为研究对象，分别对其进行0、4、6、8、10、50、100次冻融循环下的电镜扫描观测试验，得到对应次数下的微观照片，对其从颗粒形态、连结方式、排列形式对孔隙的影响三方面进行分析，并且将微观照片中出现的颗粒接触方式以几何模型的方式进行归类，研究几何模型随冻融循环次数增加后的变化规律。结果表明：随着冻融循环次数的增加，土颗粒大小朝着均一性的方向发展，平均粒径呈先减小后增大趋势；颗粒的连结形式从面胶结为主逐渐演变为点接触为主最终再回归为面胶结为主；土体在0~6次冻融循环时孔隙率呈下降趋势，6~8次冻融循环时孔隙率快速上升，之后随着冻融循环次数的增加孔隙率逐渐减小；粒状粒子几何模型变化规律从棱边接触逐渐过渡为粒面接触，扁平状粒子几何模型变化规律从初始粒面接触为主逐渐演变为棱边接触为主，最终再演变为粒面接触。
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| 关 键 词： | 黄土 冻融循环 电子显微镜 微观结构 几何结构 |
| 收稿时间： | 2019-10-30 |
| 修稿时间： | 2021-01-22 |
Study on geometric type changes of Fuping loess microstructure under freeze-thaw cycles |
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| FU Xiangyu,ZHANG Ze,YANG Chengsong,YUN Qingfei,MING Jiao.Study on geometric type changes of Fuping loess microstructure under freeze-thaw cycles[J].Journal of Glaciology and Geocryology,2021,43(2):484-496. |
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| Authors: | FU Xiangyu ZHANG Ze YANG Chengsong YUN Qingfei MING Jiao |
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| Institution: | 1.College of Civil Engineering and Mechanics，Lanzhou University，Lanzhou 730000，China;2.State Key Laboratory of Frozen Soil Engineering，Northwest Institute of Eco-Environment and Resources，Chinese Academy of Sciences，Lanzhou 730000，China;3.Institute of Cold Regions Science and Engineering，School of Civil Engineering，Northeast Forestry University，Harbin 150040，China |
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| Abstract: | The freeze-thaw cycles can cause damage to the infrastructure by affecting the soil structure in cold regions， and the macrostructure change is caused by the freezing and thawing effect that able to change the microstructure of soil. In order to explore the law of soil microstructure change under freezing and thawing， this paper takes Fuping loess with specific dry density as the research object， and performs electron microscopy scanning after 0， 4， 6， 8， 10， 50 and 100 freeze-thaw cycles. Experiments were carried out to obtain microscopic photographs. The microscopic photographs were analyzed from the three aspects of particle morphology， bonding mode and arrangement form， and the particle contact modes appearing in the microphotographs were classified by geometric model. Study the variation of the geometric model with the increase of the number of freeze-thaw cycles. The results show that with the increase of the number of freeze-thaw cycles， the size of soil particles develops toward uniformity， and the average particle size decreases first and then increases. The joint form of particles gradually changes from surface cementation to point contact. The main final regression is the surface cementation； the porosity of the soil decreases during 0~6 times freeze-thaw cycles， and the porosity increases rapidly during the 6~8 times freeze-thaw cycles， and then the number of freeze-thaw cycles increases. The porosity gradually decreases. The variation of the geometric model of granular particles gradually changes from edge contact to grain contact. The variation of geometric model of flat particles gradually changes from initial grain contact to edge contact， and finally evolves to grain contact. |
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| Keywords: | loess freeze-thaw cycles electron microscope microstructure geometric structure |
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