Influence of bedding orientation on the anisotropy of hydraulic conductivity in a well-sorted fluvial sediment  

作　　者：Dong-hui CHENG Xun-hong CHEN Ai-di HUO Min GAO Wen-ke WANG 

机构地区：[1]School of Environmental Sciences and Engineering,Chang'an University [2]School of Nature Resources,University of Nebraska-Lincoln,NE 68583-0996,USA.

出　　处：《International Journal of Sediment Research》2013年第1期118-125,共8页国际泥沙研究（英文版）

基　　金：funded by National Natural Science Foundation of China(41072183,41072184);the Special Fund for Basic Scientific Research of Central Colleges,Chang' an University(CDH2011ZD019);supported by the program for Changjiang Scholars and Innovative Research Team of Chinese Ministry of Education (IRT0811)

摘　　要：The paper describes a permeameter test method for determination of the hydraulic conductivity （K） along multi-directions in fluvial sediments with cross beddings. Unlike existing in-situ permeameter methods that determine hydraulic conductivity for submerged streambeds, our method was intended to measure hydraulic conductivity of exposed streambeds or fluvial sediments. The method was applied to the Wei River, Shaanxi Province, Central China for characterization of the anisotropy of K in a well-sorted fluvial sediment. The results illustrated that even in well-sorted sediments, cross-bedding and sediment fabrication （or texture） can lead to varied K values along different measurement directions. The K value was the largest along the dip direction （or the major direction） that is parallel to the orientation of cross bedding and the smallest in the direction perpendicular to the bedding （or the minor direction）. The K value in a given direction between the major and minor direction often fell in the range bounded by the K values in the major and minor directions. The anisotropy ratio of K （the ratio of K value between the major and minor directions） in two trenches for this well-sorted fluvial sediment was up to 1.14 to 1.23, respectively. Our results also demonstrated that even for well-sorted sediments, the K values between two sampling points only about 10 cm apart can differ. It is clear that the K distribution strongly correlates to the bedding orientation.The paper describes a permeameter test method for determination of the hydraulic conductivity （K） along multi-directions in fluvial sediments with cross beddings. Unlike existing in-situ permeameter methods that determine hydraulic conductivity for submerged streambeds, our method was intended to measure hydraulic conductivity of exposed streambeds or fluvial sediments. The method was applied to the Wei River, Shaanxi Province, Central China for characterization of the anisotropy of K in a well-sorted fluvial sediment. The results illustrated that even in well-sorted sediments, cross-bedding and sediment fabrication （or texture） can lead to varied K values along different measurement directions. The K value was the largest along the dip direction （or the major direction） that is parallel to the orientation of cross bedding and the smallest in the direction perpendicular to the bedding （or the minor direction）. The K value in a given direction between the major and minor direction often fell in the range bounded by the K values in the major and minor directions. The anisotropy ratio of K （the ratio of K value between the major and minor directions） in two trenches for this well-sorted fluvial sediment was up to 1.14 to 1.23, respectively. Our results also demonstrated that even for well-sorted sediments, the K values between two sampling points only about 10 cm apart can differ. It is clear that the K distribution strongly correlates to the bedding orientation.

关 键 词：Cross bedding Hydraulic conductivity ANISOTROPY On-site permeameter test Fluvial sediment 

分 类 号：TV143[水利工程—水力学及河流动力学]