道路生态滤沟回填黄土毛细持水特性试验研究  

Experimental Study on Capillary Water-Holding Characteristics of Loess Backfill in Ecological Ditches

作　　者：南亚林[1,2] 张晓玉 陈鸿 安鹏 刘魁[1,2] CAMARA Ibrahima Kalil[3] NAN Yalin;ZHANG Xiaoyu;CHEN Hong;AN Peng;LIU Kui;CAMARA Ibrahima Kalil(China Electronic Research Institute of Engineering Investigations and Design,Xi’an,Shaanxi 710054,China;Soil Engineering Technology Research Center of Shaanxi,Xi’an,Shaanxi 710054,China;School of Geological and Surveying Engineering,Chang’an University,Xi’an,Shaanxi 710064,China;Western Superconducting Technologies Co.,Ltd.,Xi’an,Shaanxi 710018,China)

机构地区：[1]信息产业部电子综合勘察研究院,陕西西安710054 [2]陕西省土体工程技术研究中心,陕西西安710054 [3]长安大学地质工程与测绘学院,陕西西安710064 [4]西部超导材料科技股份有限公司,陕西西安710018

出　　处：《中外公路》2024年第4期83-90,共8页Journal of China & Foreign Highway

基　　金：陕西省自然科学基金资助项目(编号:2024JC-YBMS-314,2023-YBNY-234);信息产业部电子综合勘察研究院项目(编号:2021-DKY-W01);渭南市海绵城市建设专题研究服务项目(编号:ZCSP-渭南市-2023-00548)。

摘　　要：市政道路生态滤沟雨季积水渗透、旱季保墒是基本功能,而黄土生态滤沟回填土的设计无据可依,常导致景观植被雨季渍害或旱季枯死。为此,通过对重塑黄土进行小尺寸毛细水上升高度试验、大尺寸持水特性模型试验以及非饱和数值分析研究。结果表明:当干密度分别为1.3 g/cm^(3)、1.4 g/cm^(3)时,土柱的最终毛细水上升高度均可达到100 cm。土柱高度超过20 cm后,其含水率基本保持稳定,稳定含水率分别为30.0%、28.0%;在重塑黄土毛细水上升过程中,存在一个暂态饱和区,其中干密度越小,孔隙比越大,大孔隙数量增多,毛细吸力减弱,导致水分迁移速率较慢,同时被湿桥封闭的大气泡数量也较多,因此暂态饱和区的持续时间较长。对于1.3 g/cm^(3)的土柱,其湿润锋时程曲线的模拟值与实测值基本吻合。综合考虑黄土地层稳定的天然平均干密度、毛细水上升高度及其持水特性以及生态滤沟回填土在后期将经历反复的渗透固结与毛细作用,采用1.2 g/cm^(3)作为回填控制干密度,以确保市政道路生态滤沟中的植土在旱季仍能维持植被生长所需的土壤湿度。The municipal ecological ditches have the basic functions of accumulating water for infiltration in the rainy season and conserving moisture in the dry season.However,the design of loess backfill in ecological ditches is based on no evidence,which often leads to landscape vegetation drowning in the rainy season or dying in the dry season.For this reason,a study was carried out by remoulding loess with a small-size capillary water rise height test,a large-size water-holding characteristic model test,and an unsaturated numerical analysis.The results show that the final capillary water rise height of the soil column can reach 100 cm when the dry density is 1.3 g/cm^(3) and 1.4 g/cm^(3),respectively,and the water content of the soil column is basically stable after the height of the soil column exceeds 20 cm,with the stable water content of 30.0% and 28.0%,respectively.In the process of capillary water rise of remoulded loess,a transient saturation zone exists,in which smaller dry density indicates larger pore ratio,increased large pores,and weakened capillary suction,resulting in a slower rate of water migration.At the same time,the number of large bubbles closed by the wet bridge is also larger,so the duration of the transient saturation zone is longer.For a soil column of 1.3 g/cm^(3),the simulated value of the wetting front time curve is basically consistent with the measured value.By considering the stable natural average dry density of loess stratum,the height of capillary water rise,and its water-holding characteristics,as well as the fact that the backfill in ecological ditches will undergo repeated infiltration,consolidation,and capillary action in the later stage,1.2 g/cm^(3) is adopted as the dry density for backfill control,so as to ensure that the planting soil in the municipal ecological ditches can still maintain the soil humidity necessary for the growth of the vegetation in the dry season.

关 键 词：生态滤沟 回填黄土 毛细水上升 模型试验 数值模拟 

分 类 号：U416[交通运输工程—道路与铁道工程]