非饱和土基质吸力对溶质Br^-垂向迁移影响试验研究  

Effect of Matric Suction on Vertical Migration of Solute Br^- in Unsaturated Soil

作　　者：王成文 王在敏[2] 任启欣 WANG Chengwen;WANG Zaimin;REN Qixin(Ningxia Highway Survey and Design Institute Co.,Ltd.,Yinchuan 750001,China;Laboratory of Geohazard Prevention and Geoenvironment,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]宁夏公路勘察设计院有限责任公司,宁夏银川750001 [2]成都理工大学地质灾害防治与地质环境保护国家重点实验室,四川成都610059

出　　处：《人民珠江》2019年第2期14-20,共7页Pearl River

基　　金：地质灾害防治与地质环境保护国家重点实验室团队重点课题"非饱和带溶质迁移转化规律试验研究"(SKLGP2011Z001);基于土壤孔隙分形的水动力弥散特征研究(17ZA0041)

摘　　要：研究非饱和土溶质迁移的影响因素对控制溶质污染及防治措施均有着积极意义。通过室内非饱和土柱淋溶试验,在3种质地和两种初始含水率条件下研究土中基质吸力对溶质Br^-垂向迁移的影响。结果得出,在连续降雨条件下,3种质地土的基质吸力均呈"上升—聚降—平稳"的变化趋势,其中粉黏土降雨历时比砂壤土和细砂土分别慢60、100 h,其基质吸力相比最大,最大值达84. 07 k Pa;在各含水率条件下,较低含水率土中基质吸力变幅更大,表现更为活跃;另外,溶质Br^-垂向迁移受基质吸力影响显著,在低基质吸力段内(小于20 k Pa),Br^-浓度随基质吸力的减小而骤降,而在较高吸力段上(大于20 k Pa),Br^-浓度随基质吸力的减小呈增大趋势。因此,通过调节土壤理化性质,改变土中基质吸力来控制溶质迁移,缓减或防治土壤污染。The study on the influencing factors of solute migration in unsaturated soil has positive significance for controlling solute pollution and measures.Through indoor unsaturated soil-column leaching experiment,this paper devoted to study the influence of soil matrix suction on the vertical migration of solute Br-under three soil textures and two types of initial water content.The result was as follows,under the condition of continuous rainfall,the matrix suction of three soil species showed the same tendency of“rise-sudden drop-smooth”,however,the rainfall duration of silty clay was 60 h shorter than that of sandy loam and 100 h shorter than that of fine sand,meanwhile its matrix suction was the strongest with a maximum of 84.07 kPa.In soils with different initial water contents,the matrix suction of soil with lower water content was more active and had a relatively wider variation range.The vertical migration of solute Br^-was distinctly effected by soil matrix suction,and the law was different among different suction scope.In low suction range(<20 kPa),the Br^-concentration was sharply dropping with the reduction of matrix suction.However,in higher suction range( >20 kPa),the Br^-concentration was gradually increasing with the reduction of matrix suction.In conclusion,the soil contamination could be relieved or prevented by controlling solute migration through adjusting soil physicochemical property to change the soil matrix suction.

关 键 词：基质吸力 溶质迁移 非饱和土 土柱试验 含水率 

分 类 号：S152.7[农业科学—土壤学] TU42[农业科学—农业基础科学]