Study on mechanical properties and embankment instability of dispersive clay under plane strain conditions in Songnen Plain China

Abstract

Dispersive clay is widely distributed in the Songnen Plain of northeast China, causing serious embankment damage to hydraulic engineering, and the research on the relevant failure mechanism is still incomplete. In this study, based on the real stress path of dispersive clay failure, a mechanical experimental method under plane strain conditions was adopted to investigate the strength properties of dispersive clay. The results showed that under plane strain conditions, the stress-strain curve of dispersive clay exhibited the strain hardening type, distincted from the conventional strain softening type under triaxial vertical conditions, and the strength difference was approximately twice at a consolidation stress of 50 kPa. The stress-strain relationship of the principal stress also showed the strain hardening type, and the relationship between the stress-strain was approximately linear. Under low consolidation stress, the coefficient of the intermediate principal stress reached 0.44, indicated a significant influence of the intermediate principal stress on the strength of the clay. Under low consolidation stress, the failure mode of dispersive clay was characterized by swelling with no obvious spatial shear band, while under high consolidation stress, the failure mode exhibited a shear band located diagonally. Additionally, the strength properties of dispersive clay were weakened by the leaching of chemical ions in the clay, showed different compaction and strength under different consolidation stresses.