Reexamination of collapse failure of fine-grained soils and characteristics of related soil indexes

Abstract

The reexamination of the failure of the fine-grained soils through the laboratory undrained cyclic loading tests demonstrates that some special fine-grained soils follow a different failure pattern. Indeed, compared with typical fine-grained soils, these special fine-grained soils show an obvious “collapse failure” pattern. In this context, five basic dynamic properties of the fine-grained soils with a collapse failure characteristic, namely the axial (or shear) strain, the excess pore water pressure, the effective cyclic stress path, the hysteresis curve, and the viscous energy dissipation, are described in detail, and all the properties indicate the characteristics of collapse failure in the final loading stage. The reinvestigation of the traditional behaviour classification suggests that the behaviour of the fine-grained soils with a collapse failure characteristic can be classified as either “cyclic mobility with limited liquefaction” or “cyclic mobility with larger liquefaction potential” that shows more pronounced liquefaction characteristics. Additionally, the assessment of the soil indexes of the fine-grained soils with a collapse failure characteristic reveals a certain regularity in their particle size characteristics; in fact, the clay content, the plasticity index, and the ratio of the water content to the liquid limit of the fine-grained soils range from 3.0 to 20.0%, from 0 to 9.6, and from 0.85 to 1.11 respectively. The results of the current work confirm that the fine-grained soils with limited ranges of the soil indexes have the potential to exhibit collapse failure. The findings obtained herein make a major contribution to our understanding of the collapse failure of fine-grained soils.