非饱和砾石土土水特征曲线研究  

Research on Soil Water Characteristic Curve of Unsaturated Gravel Soil

作　　者：马少坤[1,2] 唐晓菲 李少龙[3] 张捷 刘莹[1,2] 段智博 MA Shaokun;TANG Xiao-fei;LI Shao-long;ZHANG Jie;LIU Ying;DUAN Zhi-bo(College of Civil Engineering and Architecture,Guangxi University,Nanning 530004,China;Key Laboratory of Disaster Prevention and Structural Safety,Guangxi University,Nanning 530004,China;Key Laboratory of Geotechnical Mec hanics and Engineering of Ministry of Water Resources,Yangtze River Scientific Research Institute,Wuhan 43000,China)

机构地区：[1]广西大学土木建筑工程学院,南宁市530004 [2]广西大学工程防灾与结构安全重点实验室,南宁市530004 [3]长江科学院水利部岩土力学与工程重点实验室,武汉市430010

出　　处：《公路》2020年第5期34-42,共9页Highway

基　　金：国家自然科学基金资助项目,项目编号51068002、51678166;广西岩土力学与工程重点实验室资助课题,项目编号13-KF-02;中央级公益性科研院所基本科研业务项目,项目编号CKSF2017038/YT。

摘　　要：以武汉某土石坝砾石土为研究对象,采用压力板仪对9组不同级配以及不同干密度砾石土的土水特征曲线进行试验研究。研究表明,压实度越大的土样,孔径较小且分布均匀,持水能力好,排水困难。当压实度一定时,细粒较多、粗粒较少的土样排水效率高于其他粗粒较多的级配,在500kPa压力下残余含水量远低于其他级配。这与级配较不均匀的砾石土有着更低的孔隙率密切相关。采用Brooks Corey模型、Van Genuchten模型以及Gradner模型分别对不同影响因素下的土水特征曲线进行拟合,发现Van Genchten模型与Gardner模型对砾石土拟合效果很好。将各个土样的干密度与Van Genuchten模型和Gradner模型各参数进行非线性回归,总结了非饱和砾石土干密度与Van Genuchten模型和Gardner模型参数之间的规律公式。试验数据可为日后非饱和土的研究提供参考。Taking the gravel soil of an earth-rock dam in Wuhan as the research object,experimental studies are carried out by means of pressure plate instrument for soil-water characteristic curves under 9 groups of different gradations and gravel soil of different dry density.Results shows that soil sample with higher compactness has smaller pore size and uniform distribution,good water holding capacity and difficult in drainage.When the degree of compaction is constant,the soil sample with more fine particles and less coarse particles has higher efficiency of draining than that with more coarse particles.The residual water content under the pressure of 500 kPa is much lower than other two grades,caused by the fact that gradation of less uniform gravel soil has lower porosity.The soil water characteristic curves under different influencing factors are well fitted by the Brooks Corey model,Van Genuchten model and Gradner model.It is found that the Van Genchten model and the Gardner model fit well on the gravel soil.The dry density of each soil sample is nonlinearly regressed with the Van Genuchten model and the Gradner model parameters.The regular formula between the dry density of unsaturated gravel soil and the parameters of Van Genuchten model and Gardner model is summarized.The test data can provide reference for the study of unsaturated soil in the future.

关 键 词：非饱和砾石土 土水特征曲线 模型拟合 压实度 

分 类 号：TU449[建筑科学—岩土工程]