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Experimental study of frost heave mechanism

冻胀机理试验研究

基本信息

批准号：
05680353
负责人：
ISHIZAKI Takeshi
金额：
$ 1.28万
依托单位：
Hokkaido University, The Institute of Low Temperature Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05680353/
关键词：
Frost Heaving Unfrozen Water Content Ice Segregation Ice Lens NMR Molecular Dynamics

项目摘要

To clarify the mechanism of frost heave phenomena, the following experiments are performed.1. Frost heave experiments using high frost susceptible soil and porous plates.2. Experiments on unfrozen water migration under the electrical field.3. Mesurement of unfrozen water content and unfrozen film thickness using neclear magnetic resonance.4. Molecular dynamics study of fluid behavior adjacent to rigid wall.The following results are obtained by this study1) We obtained the relationship between the ice segregation rate and the temperature of ice segregating surface by using layred porous plate. The experimental results showed that the ice segregation rate decresed with decreasing temperature of ice segregating surface. This was explained by the decresing unfrozen water content and increasing water viscosity with decreasing temperature.2) From a replica of vertical section of frozen sample after the frost heave experiment, the ice content was obtained with image analysis. From the experimental results, the relationship was obtained between the segregated ice content and freezing speed and temperature gradient.3) From the frost heave experiments under the electrical field, the movement of unfrozen water was measured. The result showed that the amount of electro-osmotic flow was conperable to the water redistribution during freezing.4) The unfrozen water content of frost susceptible soil was measured with neuclear magnetic resonance. The average unfrozen film thickness was calculated with total specific surface area. The results are compared with the calculated results using Van der Waals force and electric double layr.5) From the molecular dynamics study of fluid adjacent to the wall, the fluid near the wall behaved as soilid like and the self-diffusion constant became one order smaller than the bulk state.

为了阐明翻沉现象的机理，进行了以下实验。1.采用高抗冻性土和多孔板进行了冻胀试验.电场作用下未冻水迁移实验.利用核磁共振技术测量未冻水含量和未冻膜厚度.利用分子动力学方法研究了刚性壁面附近的流体行为，得到了以下结果：1）采用分层多孔板法，得到了冰的分离速率与分离表面温度的关系。实验结果表明，随着冰分凝面温度的降低，冰分凝率降低。这是由于随着温度的降低，未冻水含量逐渐减少，水的粘度逐渐增加。2）通过对冻融后的试样进行垂直剖面的复制，利用图像分析技术获得了冻融后试样的含冰量。根据试验结果，得到了分离冰含量与冻结速度和温度梯度的关系。3）通过电场作用下的冻胀试验，测量了未冻水的运动规律。结果表明，电渗流的大小与冻结过程中水分的再分布有关。4）利用核磁共振技术测定了易冻性土壤的未冻水含量。用总比表面积计算平均解冻膜厚度。5）对壁面附近流体的分子动力学研究表明，壁面附近流体表现为类固体状态，自扩散常数比体相小一个数量级。