摘要
【目的】对不同应力状态下干密度对非饱和黄土水力特性影响进行了研究,为边坡稳定性和地基沉降等工程问题提供科学指导。【方法】通过各向同性压缩(ISO)和一维压缩(1D)制备了相同初始干密度的试样,进行了一系列压力板试验和两步流出试验,分别研究了不同应力状态下干密度对非饱和黄土的持水特征曲线和非饱和渗透系数的影响。【结果】试验结果表明,应力状态对持水特征曲线有显著影响(即1D试样的持水能力高于ISO试样)。随干密度增大,持水能力差异呈现先增后减的趋势,且在初始干密度为1.45 g/cm^(3)时差异达到最大值(11.4%),主要原因是一维压缩应力状态下,土体具有更扁平的孔隙结构,其次应力状态影响进气值规律与持水能力差异相同,对脱湿速率影响较小(即小于0.01)。在给定饱和度下,ISO和1D试样的相对渗透系数差异很小(即小于0.01),这表明在本试验的研究范围内,相对渗透系数受应力状态的影响有限。此外,在给定的饱和度下,随着干密度的降低,相对渗透系数增加了约五倍。这可归因于随干密度增加,孔隙之间连通性减弱,从而使得土体中的渗透路径更复杂。
【Purposes】A study is conducted on the influence of dry density on the hydraulic properties of unsaturated loess under different stress states,providing scientific guidance for engineering issues such as slope stability and foundation settlement.【Methods】Specimens with similar dry densities were prepared by isotropic compression(ISO)and one-dimensional compression(1D).Effects of stress state and initial dry density on water retention curve and relative hydraulic conductivity of unsaturated loess were investigated through pressure plate test and two-step outflow test.【Results】Results show that the stress state has a significant impact on water retention curve(i.e.the water retention capacity of 1D specimens is larger than that of ISO specimens).With increasing dry density,difference in water retention capacity increases at the initial state,reaches the peak value(11.4%)at the dry density of 1.45 g/cm^(3),and then decreases,which is mainly due to the complex pore structure of soil specimens produced during one-dimensional stress path.In addition,the variation of difference in air entry value with respect to dry density follows a similar pattern to that in difference in water retention capacity with respect to dry density,while differences in the desorption rates between ISO and 1D specimens are less than 0.01(log kPa)^(-1),demonstrating that the stress state has insignificant effects on the desorption rate.The ISO and 1D specimens have similar relative hydraulic conductivities under given degrees of saturation(i.e.,differences<0.01),demonstrating that the relative hydraulic conduc-tivity is limitedly affected by the stress state,at least for the range investigated in this study.Furthermore,the relative hydraulic conductivities increase as large as five times with decreasing dry density under given degrees of saturation,which is different from the predictions of existing relative hydraulic conductivity models.This is due to the worsened interconnectivity between pores with increasing dry density,which increases the tortuosity of flow path in soils.
作者
李林
周志勇
刘勇
张瑞松
唐辉
宋天琪
穆青翼
LI Lin;ZHOU Zhiyong;LIU Yong;ZHANG Ruisong;TANG Hui;SONG Tianqi;MU Qingyi(Shandong Electric Power Engineering Consulting Institute Co.,Ltd.,Jinan,Shandong,China;China JIKAN Research Institute of Engineering Investigations and Design,Co.,Ltd.,Xi’an,Shaanxi,China;School of Human Settlements and Civil Engineering,Xi’an Jiaotong University,Xi’an,Shaanxi,China;School of Geological Resources and Surveying Engineering,Chang’an University,Xi’an,Shaanxi,China)
出处
《太原理工大学学报》
北大核心
2025年第5期1047-1053,共7页
Journal of Taiyuan University of Technology
基金
国家自然科学基金面上项目(52279109)
陕西省重点研发计划项目(2024GX-YBXM-566)。
关键词
持水特征曲线
相对渗透系数
应力状态
初始干密度
water retention curve
relative hydraulic conductivity
stress state
initial dry density
