Evolution of Undrained Strength Under a Test Embankment

Paper in proceedings, 2021

Increased traffic and environmental loads necessitate re-evaluation of the stability of existing road and railway embankments built on soft sensitive clays. Thus, the current mobilised undrained shear strength needs to be quantified. A methodology to evaluate changes in undrained shear strength under embankment loading is developed and applied for the case of Haarajoki test embankment. The methodology combines boundary value modelling of embankment loading with integration point level stress path probing using the Creep-SCLAY1S model. The changes in the stress state and the relevant state parameters resulting from the boundary value modelling enable the quantification of the mobilised undrained shear strength. The results indicate an increase in the undrained shear strength up to 17% in the most affected clay layer. The high pre-overburden pressure in the top of clay deposit prevents significant changes in the undrained shear strength in the case of Haarajoki. Thus, when assessing changes in the undrained shear strength, one of main parameters to determine is the initial preconsolidation pressure.