Suitability of Different Approaches for Analyzing and Predicting the Behavior of Decomposed Volcanic Rocks: Fid-Bau Portal

Suitability of Different Approaches for Analyzing and Predicting the Behavior of Decomposed Volcanic Rocks

Okewale, I. A. / Coop, M. R.

Based on a detailed investigation of decomposed volcanic soils from Hong Kong, an extensive analysis has been made of the best approaches for prediction and description of the behavior of the decomposed volcanic rocks, materials that are commonly encountered by practicing engineers worldwide. The parameters considered were compressibility, strength, and in situ specific volume, and the indices considered were plasticity, a grading descriptor (fines content), mineralogy (clay minerals and quartz), and chemical weathering indices. The sampling depth and chemical weathering indices are the most appropriate factors to predict the compressibility of the decomposed volcanic rocks. The strength will be satisfactorily predicted by fines content, clay minerals, plasticity, and chemical weathering indices, whereas the depth, plasticity, and chemical weathering indices are most appropriate for predicting the in situ specific volume. The various approaches (depth, fines, mineralogy, plasticity, and chemical weathering indices) are each suitable for different parameters and are therefore recommended for practicing engineers working on these geomaterials, depending on which properties are needed.