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干密度对击实黄土土水特征曲线影响的试验研究

Experimental research on the effect of dry density on soil-water characteristic curve of compacted loess

中文摘要英文摘要

土的矿物成分和孔隙结构是影响土水特征曲线的基本因素,其它因素往往通过影响这两个基本因素而起作用,探索干密度通过影响土体孔隙结构对土水特征曲线的影响情况是一个很重要的理论课题。本文采用Ku非饱和导水率测量系统,实测了兰州黄土不同干密度击实土样的土水特征曲线,通过比较分析得出:以饱和度表示的不同干密度土体的土水特征曲线,沿着右斜向上的方向,呈现出干密度增大的规律;土体干密度越大,进气值就越高,持水能力就强,曲线就越平缓的规律;干密度大的土样在饱和度降低过程中,脱水速率低于干密度小的土样,同时当基质吸力较高时,初始干密度大的土样含水率大于初始干密度小的土样。对上述结论,通过分析击实土样的扫描电镜图片,统计并比较其孔隙结构变化情况,从击实黄土微结构方面做了一定的理论解释。最后用Van Genuchten模型和Frelund和Xing方程对实测土水特征曲线做了拟合,结果表明,Van Genuchten模型能更好地拟合本次试验结果,同时给出了拟合参数。

he mineral composition and pore structure of soil are the basic factors to affect the soil-water characteristic curve, and the effect of other factors often works through these two basic factors. It is thus a very important theoretical topic to explore the effect of dry density over the soil-water characteristic curve through exerting an effect on the porous structure of soil. In this paper, soil-water characteristic curve of different dry density of Lanzhou loess is measured by using Ku unsaturated hydraulic conductivity measurement system, and the result shows: In the figure containing three characteristic curves, in terms of saturation, of soil water with different soil dry densities, the dry density tends to be increasing from right-inclined outwards;the greater the dry density of soil, the higher the air-entry value grows, and the stronger the capacity of holding water becomes, so the more gentle the curve tends to be;Furthermore, when the saturation of soil samples is reducing, the dehydrating rate of the soil samples with a greater dry density is slower than that of those with a smaller dry density, meanwhile when the matrix suction capacity is rather high, the moisture content of the soil samples with a larger dry density is greater than that of those with a smaller dry density. Through analyzing electron microscope images scanned from compacted soil samples, making a statistic survey and comparing the changes in the pore structures, the present study has offered certain theoretical explanation to this law from the perspective of the micro-structure of compacted loess. In the end, using Van Genuchten model, Frelund and Xing equation makes a fitting to the measured SWCC curve. The result shows that Van Genuchten model can well fit the experimental results, and the fitting parameters are given.

吕擎峰、蔡汉成、马向贤、赵彦旭、梁晓波

水利工程基础科学

干密度击实黄土孔隙结构土水特征曲线Van Genuchten模型

dry densitycompacted loesspore structuresoil-water characteristic curveVan Genuchten model

吕擎峰,蔡汉成,马向贤,赵彦旭,梁晓波.干密度对击实黄土土水特征曲线影响的试验研究[EB/OL].(2009-07-24)[2025-08-18].http://www.paper.edu.cn/releasepaper/content/200907-535.点此复制

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