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J. Hefei Univ. Tech. (Nat. Sci.)

合肥工业大学学报(自然科学版)

JOURNAL OF HEFEI UNIVERSITY OF TECHNOLOGY (NATURAL SCIENCE)

Competent Authorities: Ministry of Education of the People's Republic of China

Sponsor by: Hefei University of Technology

ISSN 1000-1646, CN 34-1001/N

Study on the performance of microwave modified expansive soil under freeze-thaw cycles

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微波改良膨胀土冻融循环作用下的性能研究

Journal Information

J. Hefei Univ. Tech. (Nat. Sci.), Jan.2025, Vol.48 No.1: 119-126

DOI: 10.3969/j.issn.1003-5060.2025.01.018

Authors

WANG Pengcheng, LIU Ming

(School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei 230009, China)

Abstract and Keywords

Abstract: In this paper, the effect of cyclic freezing and thawing on the physical and mechanical properties of expansive soil improved by microwave heating is studied. The industrial microwave oven is used to heat the expansive soil at high temperature for different times to improve the original expansive soil. The volume deformation, compressive strength, X-ray diffraction (XRD) and microstructure tests were carried out on the samples after 0, 1, 3, 6 and 10 cycles of freeze-thaw. The results showed that under the optimum moisture content, the soil samples at different microwave times show "freeze shrinkage and thaw expansion" during the cyclic freeze-thaw process. The unconfined compressive strength and elastic modulus of expansive soil after microwave heating under freeze-thaw cycles decrease with the increase of freeze-thaw cycles, especially at the beginning stage. Under the same freezing and thawing times, the strength and elastic modulus of the improved expansive soil by microwave heating increase with the increase of microwave time, and the microwave effect effectively reduces the freezing and thawing damage. The effect of freeze-thaw cycles on micro-pore area of microwave modified expansive soil is as follows: the more freeze-thaw cycles, the higher the proportion of large pore area, and the lower that of small pore area. It shows that the freeze-thaw cycles have a great impact on the soil structure.

Keywords: freeze-thaw cycle; microwave heating; expansive soil; MATLAB software; microscopic characteristics

作者信息

汪鹏程，刘明

(合肥工业大学土木与水利工程学院, 安徽合肥 230009)

摘要和关键词

摘要: 文章针对冻融循环作用下微波加热处理膨胀土的有效性问题进行相关试验测试, 利用工业微波炉对膨胀土分别进行不同时间微波高温加热改良, 对经过 0、1、3、6、10 次冻融循环作用后的试样进行体积变形、抗压强度、X 射线衍射(X-ray diffraction, XRD)和微观结构试验。结果表明: 在最佳含水率下, 不同微波加热时间下的试样在冻融循环过程中均表现为“冻缩融胀”; 冻融循环作用下微波加热后的膨胀土试样无侧限抗压强度和弹性模量均随冻融循环次数增加而降低, 尤其在开始阶段影响最大; 相同冻融循环次数下, 微波加热改良后的膨胀土土体强度和弹性模量均随微波加热时间增加而增加, 微波加热作用有效地降低了冻融破坏作用; 冻融循环作用对微波加热膨胀土试样微观孔隙面积的影响呈现随冻融循环次数的增加, 大孔隙面积占比增多, 而小孔隙减少, 表明冻融循环作用对土体结构性影响很大。

关键词: 冻融循环；微波加热；膨胀土；MATLAB软件；微观特性

Funding

国家自然科学基金资助项目（12272119）；国家自然科学基金联合基金资助项目（U1965101）

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