Experimental Study Of Water And Salt Movement In The Loess

On the basis of consulting to a number of literatures both at home and abroad, thepresent situation and trend of study on water-salt transportation are summarized in thispaper According to the present Study directions and achievements, and combining withthe concrete contents of" study on theories and coupling models of solute transport inthe Loess area", which is founded by the NSFC, the laws of the salt transport in Loesshave been researched by indoor experiments mainly The concrete contents are listed asfollows.The influences on the water infiltration into soil, caused by the walls of soilcontainers, salt content, initial moisture, and coarse sand layers, are analyzed in thispaper. They have been discussed in many literatures, but the special experiment analysisis not very much. In this paper, according to the real conditions of our laboratory theyare analyzed briefly We can see they have much more influence on the waterinfiltration.There have been a lot specifications on the laws of K+ transport characteristics,however, no report has been found on K+ transport characteristics in the Loess. Analyticindexes such as barycenter coordinates, characteristic width and height are introduced tostudy variation process of K+ and electric conductivity under leaching condition. Alsothe relationship between content of K+ and electric conductivity is analyzed on saltprofiles. Result shows that the relationship is not unique function and that can be fittedby linearity and quadratic equation. With water infiltration and downward movement ofsalt profiles, no distinct changes appear in the function.Research on water movement and solute transport in layered soil has beenconcentrated on clay layer, however, less work has been done on soil with sand layerespecially on salt movement characteristics under this condition. Experiment study hasbeen carried out on analyzing the influence of sand layer on relationship between thecontent of K+ and electric conductivity The influence of sand layer on salt movement,due to water-tight function, is studied, at the same time, the way salt travel through sandlayer is discussed. Result shows that the concentration of K+ doesn't change much inwater accumulation process with the increase of K+ content above the interface betweensoil and sand, which also demonstrate that K+ moves together with water by dissolvingin it.