The adsorption of contaminants is one of the key mechanisms governing the transport of contaminants in the clay liner at landfill sites. This study presents an investigation of some factors controlling the adsorption of potassium (K+) onto two soils, named Ariake clay and Akaboku soil. The KCl solution and multi-salt solution containing KCl, NaCl and CaCl2 were selected as the synthetic leachates. The results show that with the increase of the solid/solution ratio, the adsorbed amount of K+ decreased for both soils. This dependence of adsorption behavior on the solid/solution ratio was found more significant for the Ariake clay. Both soils arrived an equilibrium condition in short time less than the contact time prescribed by the ASTM and US EPA standard batch-type tests. It was observed that both soils adsorbed larger amount of K+ in the case of KCl solution condition than in the case of multi-salt condition.

Soils are generally penetrated by a pore system. Most transport processes usually occur in pore space of soils. The description of pore space shape is necessary to quantify how the geometry in-uences the percolation of substances such as water and nutrients. In this paper, the pores in soils are described by fractal geometry, and the fractal dimension is obtained from porosimetric measurements. The water permeability function is studied to correlate with the pore-size distribution of unsaturated soils, and is derived from the fractal model of pore-size distribution. The comparisons between the collected data of permeability and the proposed permeability function show that the calculations of the proposed permeability function are in satisfactory agreements with the measurements.

Great efforts have been made to determine the shear strength of unsaturated soils using both elaborate laboratory tests and empirical methods. However, elaborate laboratory tests are difficult and time consuming to perform, and the physical meaning of empirical parameters is not obvious in empirical methods. A simple method to determine the unsaturated shear strength is proposed based on a fractal model for the pore surface. The unsaturated shear strength can be easily estimated using the surface fractal dimension and air-entry value, which can be calculated from the soil-water characteristic curves. The unsaturated shear strength obtained from the proposed method is in satisfactory agreement with the experimental data found in the literature. The proposed method is critically examined and its advantages and limitations are also discussed.

A significant 'size effect' is observed in ice failure strength: the ice strength is not independent of ice fragment size, but decreases with increasing size. The fractal approach to the ice mechanics with a multiscale microstructure provides an elegant and unified explanation of the size effect on ice failure strength. Ice fragments are found to have a fractal size distribution, with a fractal dimension (D) close to 2.50 over a remarkably wide range of ice fragment size. The size effect on ice strength can be well predicted using the fractal dimension D=2.50 of the ice fragment size distribution.

Soil surface area does not keep constant and varies with the yardstick. Experimental results show that the amount of molecules absorbed in the surface monolayers is a function of absorbate size. The surface topography of soils from a few up to as many as thousand angstroms is very well described by fractal dimension, Ds. The surface fractal dimension, Ds is usually used to measure the irregularities of soil surface. The surface fractal dimensions of kaolin, montmorillonite and other six soils are measured using the adsorption method. The surface fractal dimensions of kaolin and montmorillonite are examined by the values measured using the nitrogen/water isotherm adsorption. The relationship between the surface fractal dimension and the content of clay is also discussed in this paper.