Comparison of 2D and 3D images of fractures in a Vertisol

Use of sequential images of an impregnated soil block (6 x 2 x 2 cm) were used to compare two dimensional (2D) and three dimensional (3D) aspects of pores in an Italian Vertisol. Standard image analysis methods are used to represent and measure the properties of the pores represented in the images. It is clear that not all 3D properties can be predicted with the same precision using 2D images. This is largely due to anisotropy of the Vertisol pore structure. However, it was found that many properties such as porosity, pore width distribution can be adequately assessed using five to ten 2D sections in the 3D block. Measurements such as fractal dimension can be determined with fewer 2D images. However, pore connectivity and percolation threshold dimensions cannot be predicted using a small percentage of the soil block volume in 2D images. Connectivity observed in 2D and 3D images is very different in this soil example. (C) 1999 Elsevier Science B.V. All rights reserved.