Laboratory Experiments Research For NaCl Transportation In The Groundwater

The study of groundwater pollution theory in China is in an early stage, eventhough the pollution in the country is serious. This article’s experiments uses sodiumchloride(NaCl) as the conservative solute. Laboratory experiments which consists onedimensional soil column with clay, middle sand, clay with fine sand, sand with fly ashare done. Indoor experimental box is used to study the three dimensionaladvection-dispersion theory by monitoring the sensors in it when the hydraulicgradient were given. Applying SEEP/W and CTRAN/W from GeoStudio software,and Visual MODFLOW simulate the experiment. Experiments results are as follows:1. Owing to adsorption-desorption, observed curves in the clay are not strictnormal curves. The calculated dispersion is not a fixed value, but increases with thedistance of contaminant transportation. Sand experiment has the larger uncertaintythan clay, the dispersion of sand is smaller than clay. From curves obtained from thepoints with different distance from source,"initial memory" is observed which showssimilar curve details.2. The mixture of fine sand and clay tests show that the various content of claycannot obviously influence the curves peak. Fly ash has the stronger capability ofadsorption than clay.3. The three dimensional test box shows the ascent stage of transversemonitoring points’ curves is more gradual than longitudinal ones. SEEP/W andCTRAN/W, Visual MODFLOW can simulate the experiments well. A pumping wellis installed with the software which prove the well has the ability to control thecontaminant transportation.