ISSN 1000-3665 CN 11-2202/P

    残坡积碎石土毛细水上升高度模型试验研究

    Experimental study on capillary rise in eluvium-deluvial gravelly soil

    • 摘要: 毛细水上升带的高度及其水分分布会影响毛细带土的渗透性和强度,在残坡积碎石土斜坡稳定性评价时,需要确定其中的毛细水上升高度及水分剖面。为了揭示残坡积碎石土毛细水上升规律,针对其粒径特点,改进了现有毛细水上升测试装置,并设计了2种干密度、7种细/粗粒含量比例,共14个碎石土土柱,进行了毛细水上升高度及上升过程中土柱不同高度截面处的含水率测试。基于试验成果,得到了密度及细/粗粒含量比例对毛细水上升的影响规律,提出了利用碎石土细粒含量预测毛细水上升高度的函数。试验表明:残坡积碎石土毛细水上升高度随着细粒含量的增加而增大;相同细/粗粒配比下,较大干密度的碎石土毛细水上升较大;细粒含量越高,土柱最终稳定体积含水率越高,且较大干密度土柱的最终稳定体积含水率基本上均大于较小干密度的土柱。试验中各干密度及配比碎石土试样柱的毛细水上升稳定高度不超过1.0 m,表明研究区残坡积碎石土中稳定的地下水位对上部土体含水率的影响范围是有限的。相关研究成果可为山区残坡积碎石土斜坡稳定性、地质灾害风险评估及预警性计算提供参考。

       

      Abstract: The height of capillary water rise and its moisture distribution influence the permeability and strength of capillary zone soils. Therefore, determining the capillary rise height and moisture profile is essential for evaluating the stability of slopes composed of eluvium-deluvial gravelly soil. To investigate the capillary rise behavior in such gravelly soils, considering their particle size characteristics, an existing capillary water rise testing apparatus was improved based on its particle size characteristics. The improved testing apparatus was then utilized to conduct capillary water rise height measurements and moisture content tests at different height sections of 14 gravelly soil columns under two dry densities and seven fine/coarse particle content ratios. Based on the experimental results, the influence of density and fine/coarse particle content ratio on capillary water rise was analyzed, and a function for predicting capillary water rise height using fine particle content in gravelly soil was proposed. The results reveal that the capillary rise height in eluvium-deluvial gravelly soil increases with the fine particle content and dry density. The test findings further indicate that eluvium-deluvial gravelly soil with higher fine particle content and greater dry density exhibit significantly elevated stable volumetric moisture content in the soil columns. The stable height of capillary water rise in all tested gravelly soil columns did not exceed 1.0 m, indicating that the influence of the stable groundwater level on the moisture content of the overlying eluvium-deluvial gravelly soil is limited in the study area. The study results can serve as a reference for slope stability assessment, geological risk evaluation, and early warning systems in mountainous areas with eluvium-deluvial gravelly soil.

       

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