The Research Of The Toxic And Harmful Substances Infiltrating In The Soil

Environmental Geotechnology is one of the new intercrossed subjects, including knowledge of many other subjects, such as Geotechnical Engineering, Environmental Engineering, Agrology, Geology Engineering, Sanitary Engineering, Agriculture Engineering, Mineral Engineering, etc. It has been made great progresses since it was founded in 1986.Contaminant transportation and transformation in soil is an important basic and fundamental problem on protecting soil from environmental deterioration and engineering characteristic metamorphosis. In this paper, the author summarized the definition of Environmental Geotechnology, discussed its research fields, and sketched its previous developments, gave the detailed review on previous researches on contaminant transportation and transformation, and pointed out the unsolved issues and the directions of the problem.Theoretical foundations of contaminant transportation and transformation in soil were indicated, and the style of the contaminant transportation process in soil was provided, then the mechanism of contaminant transportation and transformation in soil was analyzed, the reactions between the contaminant and soil were also discussed.Analytical solutions and numerical modeling were presented to investigate contaminant transportation and transformation in soil in this study.This paper described the initial and boundary conditions which were used to form the mathematical models. An analytical solution of the one-dimensional transport equation with time-dependent dispersion coefficient and time varying porous velocity was obtained. The model was based on the advection-dispersion equation, and the dispersion coefficient and the porous velocity coefficient were depended on the seepage time of the contaminant from a single input source. The time-dependent dispersion coefficient and porous velocity coefficient can be assumed as arbitrary functions.In this paper, the numerical calculation solving the one-dimensional transport equation with time-dependent dispersion coefficient and time varying porous which the contaminant transport in soil was also made, some useful results were achieved.