压实度对宽级配土水力特性的影响研究  

Influence of compaction on hydraulic properties of widely-graded soil

作　　者：刘丽[1] 吴羊 李旭[1] 赵煜鑫 LIU Li;WU Yang;LI Xu;ZHAO Yu-xin(Key Laboratory of the Ministry of Education of Urban Underground Engineering,Beijing Jiaotong University,Beijing 100044,China;China Construction America Inc.,Jersey City,America)

机构地区：[1]北京交通大学城市地下工程教育部重点试验室,北京100044 [2]中建美国有限公司,美国泽西城

出　　处：《岩土力学》2021年第9期2545-2555,共11页Rock and Soil Mechanics

基　　金：中央高校基本科研业务费专项资金资助(No.2020JBM038);国家自然科学基金面上项目(No.51979002)。

摘　　要：宽级配土是修建土石坝心墙和堤防的良好填料,其水力特性决定了土石坝心墙和堤防的防渗性能。对于给定级配的土体,压实度是其水力特性的主控因素。首先通过室内试验测量压实度对宽级配土水力特性的影响规律,然后通过数据分析,建立了考虑压实度影响的水力特性模型。研究结果表明:土体压实度越高,颗粒间的大孔隙越少,土体进气值越高,饱和渗透系数越低;提出了一个考虑结合水含量的修正渗透吸力计算公式,可以很好地描述风干土的渗透吸力随含水率的变化规律;土体进气值和压实度在半对数坐标系上呈线性关系;土体饱和渗透系数和干密度在半对数坐标系上呈线性关系;回归了进气值、饱和渗透系数、非饱和渗透系数与压实度之间的经验模型,建立了针对宽级配土整个土-水力学特征曲线影响的经验计算公式,具有一定的普适性。Widely-graded soil is a good anti-seepage filling material for core of earth dams and embankment, and its impermeability is determined by its hydraulic properties. For the same soil, compaction is the primary factor that controls its hydraulic properties. In this study, the effect of compaction on hydraulic properties of a widely-graded soil is studied by laboratory tests, and through data analysis, the hydraulic property model is established, which is based on the effect of compaction. The results demonstrate that the higher the degree of compaction, the less macropores between particles of the soil, the higher the air-entry-value of the soil, the lower the saturated permeability coefficient. A prediction model of osmotic suction is proposed and it can accurately describe the changing principle of osmotic suction for unsaturated soil upon drying. The air-entry-value of the soil has linear relationship with the relative compaction on semi-log coordinate, and saturated permeability coefficient has linear relationship with the dry density on semi-log coordinate. An experiential model among air-entry-value, saturated permeability coefficient, unsaturated permeability coefficient and relative compaction is established, also an experiential calculation formula for soil-water characteristic curve(SWCC) of widely-graded soil is established, which has general applicability.

关 键 词：非饱和土 压实度 土-水特征曲线(SWCC) 饱和渗透系数 渗透系数函数 

分 类 号：TU411[建筑科学—岩土工程]