地下水位抬升对黄土高填方地基增湿影响研究  

Wetting effects of loess high-fill embankment due to groundwater uplift

作　　者：朱才辉[1,2,3] 彭森 刘争宏 张继文 ZHU Caihui;PENG Sen;LIU Zhenghong;ZHANG Jiwen(Institute of Geotechnical Engineering,Xi′an University of Technology,Xi′an 710048,China;Shaanxi Engineering Technology Research Center for Urban Geology and Underground Space,Xi′an 710068,China;Shaanxi Hydrogeology Engineering Geology and Environment Geology Survey Center,Xi′an 710068,China;China Jikan Research Institute of Engineering Investigations and Design,Co.,Ltd.,Xi′an 710043,0x09China)

机构地区：[1]西安理工大学岩土工程研究所,陕西西安710048 [2]陕西省城市地质与地下空间工程技术研究中心,陕西西安710068 [3]陕西省水工环地质调查中心,陕西西安710068 [4]机械工业勘察设计研究院有限公司,陕西西安710043

出　　处：《自然灾害学报》2023年第2期61-70,共10页Journal of Natural Disasters

基　　金：国家自然科学基金项目(52279110);陕西省重点研发计划项目(2021SF2-02,2022SF-197);陕西省公益性地质专项(202109,20180303);陕西省城市地质与地下空间工程技术研究中心开放性课题(2022KT-01)。

摘　　要：为了给黄土高填方地基施工及防排水设计提供科学参考,以某黄土高填方地基工程为例,基于填方地基内部水分场的实测资料,探讨了填方地基中含水率上升的原因,进一步采用室内试验,研究了不同初始状态下非饱和Q3黄土在增湿条件下的土水特征曲线、渗透性及强度软化函数,并最终将其引入到非饱和渗流及增湿变形分析中,量化分析了地下水位抬升对高填方地基的水分场和增湿变形的影响规律。结果表明:1)高填方地基施工完成后,地基平均含水率相比初始状态约有2%~4%的增量,局部含水率的增幅可高达20%,高填方地基的含水率有上升趋势,其产生的原因与大面积高填方堆载、基岩裂隙水迁移及压实黄土的非饱和渗流特性有关;2)非饱和压实Q3黄土在增湿条件下具有明显的强度软化特性、随着压实度和固结压力的增大,土水特征曲线坡度越缓,压实黄土的渗透系数与干密度呈幂函数关系,原状黄土的渗透系数与干密度呈线性递减关系;3)非饱和黄土地基受地下水抬升作用后,水位线以上约31.0 m土体受到增湿影响,水位线以上约10.0 m土体受增湿最为强烈,高填方地基增湿沉降与地下水位抬升高度呈线性增长关系,地下水位从3.0 m抬升至30.0 m期间,高填方地基增湿压缩比从0.14%增加至1.61%。通过文中研究,以期为高填方地基顶部基础设施的设计和施工提供参考。To provide scientific reference for construction and drainage design of the loess high-fill embankment(LHFE),taking a LHFE project as an example,based on the measured moisture field data in the fill embankment,the reasons for the increase of water content in the LHFE were discussed.The soil-water and permeability characteristics and soften regularity of unsaturated compacted Q 3 loess were investigated by laboratory tests.The unsaturated seepage field and wetting behaviour of the LHFE with groundwater uplift(GU)was quantitatively analyzed.The results show that:1)After the construction of LHFE,the average water content of the foundation increases by 2%~4%compared with the initial state,and the local water content increases by 20%.The water content of the LHFE has a rising trend,which is related to the large area of high-fill load,the water migration of bedrock fissure and the unsaturated seepage characteristics of the compacted loess.2)Unsaturated compacted Q 3 loess has obvious strength softening characteristics under wetting condition.With the increase of compaction degree and consolidation pressure,the slope of soil-water characteristic curve(SWCC)becomes slower.The permeability coefficient of compacted and undisturbed loess shows a power and a linear function relationship with dry density,respectively.3)Influenced by the GU,about 31.0 m depth of unsaturated compacted loess above the groundwater table was moistened,and 10.0 m depth of compacted loess above the groundwater table was strongly moistened.The wetting deformation of the LHFE and the rising height of the GU has a linear relation.During the height of GU rise from 3.0 m to 30.0 m,the wetting compression ratio of LHFE increases from 0.14%to 1.61%.Through this work,it is expected to provide reference for the design and construction of infrastructure on the top of the LHFE.

关 键 词：黄土高填方 地下水位抬升 增湿变形 含水率 渗流特性 

分 类 号：TU444[建筑科学—岩土工程]