Novel Approach to Consolidation Theory of Structured and Collapsible Soils

摘要

Consolidation is one of the most important concepts in geotechnics. The pioneer ideas of both Terzaghi and Biot, and its attendant phenomena have been shown to be widely applicable to a wide variety of soils. However, when structured and collapsible soils are taken into account, the standard consolidation theory ultimately requires complementary considerations to correctly predict a soil's behavior. In particular, indirect determination of permeability by means of the consolidation coefficient, c(v), tends to highly underestimate the real hydraulic behavior for these types of soil. In the present paper, a modification in the understanding of the consolidation process is proposed to adjust the prevailing theory to the reality of both structured and collapsible soils. In short, it is considered that every soil may suffer microcollapses that increase pore-water pressure momentarily during the consolidation process. The mathematical basis for the new theory is developed and a new parameter, the collapsibility index eta, is introduced. The new understanding provides an alternative explanation to the apparent low permeability observed in consolidation tests. Also, an experimental data set is analyzed in light of the concepts hereby developed. The latter analysis reveals that the alternative approach proposed predicts well the behavior of the experimental data considered. (C) 2014 American Society of Civil Engineers.