Abstract
Crack patterns occurring in mudstones and granites at various degrees of weathering intensity were characterized by multifractal analysis. In addition, physical property measurements, optical microscopic observations, particle analysis, and XRD analysis were carried out to determine textural and compositional features of the samples. By a comparison of the generalized dimension spectra derived from the analysis, the applicability of multifractal theory to crack pattern analysis was considered. Furthermore the relationships between crack patterns and textural and compositional features are discussed. The results may be summarized as follows:
1) Homogeneous crack patterns developed in mudstone samples weathered in a cyclic drying and wetting process. In weathered granite which underwent chemical weathering process, inhomogeneity of crack distribution increased with weathering intensity.
2) The homogeneous crack pattern in the mudstone samples can be attributed to the high effective porosity and fine, homogeneous mineral distribution in the matrix. The heterogeneous pattern of the granite may be due to selective weathering-durability of the constituents of the weathered granite and its holocrystalline-granular texture.
3) The generalized dimension spectra obtained by multifractal analysis reflects the complexity and homogeneity of crack pattern. And, it precisely illustrates the nature of crack patterns better than conventional fractal analysis.
4) Multifractal analysis can be effectively applied to characterize the intensity and the progress of rock weathering, and to predict the engineering properties and the weathering behavior of rock.
