干缩开裂黄褐土非饱和水平吸渗特征研究

发布时间：2018-05-25 18:16

本文选题：干缩裂缝 + 秸秆添加　；参考：《农业机械学报》2017年07期

【摘要】：通过室内水平吸渗试验,结合Matlab数字图像处理与形态学算法,在黄褐土土壤中添加秸秆模拟不同生长期作物根系密度,对干缩开裂黄褐土中的非饱和水平吸渗及湿润锋推移特征进行研究。结果表明:不同秸秆密度处理裂缝稳定形态面积密度和裂缝平均宽度差异显著(p0.05),当秸秆密度由0 cm/cm~3增加到1.5 cm/cm~3时裂缝面积密度和裂缝平均宽度分别减小为1.73%、0.071 cm,随着秸秆密度增大土壤稳定形态裂缝面积密度与裂缝平均宽度显著减小。秸秆添加间接影响入渗过程历时,但土壤最终累积入渗量无显著差异。裂缝的存在导致入渗率发生波动现象,且在入渗前中期尤为明显;未开裂土和开裂土累积入渗量随时间的变化关系均符合Kostiakov经验入渗模型,其经验参数与秸秆密度有关,拟合方程达到显著水平。引入湿润锋均匀系数对水平吸渗不均匀性进行评价,土壤裂缝面积密度及裂缝平均宽度越大入渗初期的水分不均匀性特征越明显,均匀系数随着时间推移逐渐减小;根据湿润锋推进速率随时间的变化特征,开裂黄褐土土壤的水平吸渗过程可以分为3个阶段,即初始裂隙流阶段、稳渗基质流阶段和吸渗末期阶段。
[Abstract]:Through horizontal osmotic experiment in laboratory, combining with Matlab digital image processing and morphological algorithm, straw was added to yellow cinnamon soil to simulate crop root density in different growing stages. The characteristics of unsaturated horizontal imbibition and wetting front in dry shrinkage cracking yellow cinnamon soil were studied. The results showed that there were significant differences in the stable morphological area density and the average crack width between different straw density treatments (p0.05). When the straw density increased from 0 cm/cm~3 to 1.5 cm / cm ~ 3, the area density and the average crack width of the fracture decreased to 1.73 ~ 0.071 cm, respectively, with the increase of straw density from 0 cm/cm~3 to 1.5 cm 路cm ~ 3. The density of crack area and the average width of crack decreased significantly by increasing the density of straw. Straw addition indirectly affected the duration of infiltration process, but there was no significant difference in the final cumulative infiltration amount of soil. The existence of cracks leads to the fluctuation of infiltration rate, which is especially obvious before and during the middle period of infiltration. The relationship between the cumulative infiltration amount of uncracked soil and cracked soil with time accords with the Kostiakov empirical infiltration model, and its empirical parameters are related to the density of straw. The fitting equation reached a significant level. The wetting front uniformity coefficient was introduced to evaluate the horizontal permeability heterogeneity. The larger the crack area density and the crack average width were, the more obvious the water inhomogeneity was, and the uniformity coefficient gradually decreased with time. According to the characteristics of the advancing rate of wetting front with time, the horizontal infiltration process of cracked yellow cinnamon soil can be divided into three stages, namely, initial fissure flow stage, stable infiltration matrix flow stage and late infiltration stage.
【作者单位】：河海大学南方地区高效灌排与农业水土环境教育部重点实验室;河海大学水利水电学院;
【基金】：国家自然科学基金项目(51579069、51179050) 高等学校学科创新引智计划(111计划)项目(B12032) 江西省水利科技项目(KT201507) 江苏高校优势学科建设工程项目(YS11001)
【分类号】：S152.7

【相似文献】