Strain Rate-Dependent Consolidation Behaviors of Embankment With or Without Vertical Drains

Abstract

This paper presents strain rate-dependent consolidation behaviors of soft clay at test embankment with or without vertical drains. To analyze the effects of strain rate and viscoplastic strain on consolidation behavior of drainage-installed deposit, an axisymmetric nonlinear viscoplastic model for vertical drain was proposed by using a unique effective stress-strain-strain rate relationship ( ). The proposed model can consider the difference in strain rate between the laboratory and in-situ during consolidation. In addition, it can take into account the combined processes of pore water pressure dissipation according to Darcy's law and pore water pressure generation due to viscoplastic strain. The strain rate that occurred in the drainage-installed deposit (zone B) under the embankment is 10 times greater than that in soft clay without vertical drain (zone A). Preconsolidation pressure is larger in zone B than in zone A due to the difference of strain rate. Increase in excess pore water pressure was observed in zone A after the end of construction, but not in zone B. Increase in excess pore water pressure may be induced by viscoplastic strain.