Electro-osmotic-assisted consolidating of undisturbed soft sensitive clay

Electro-osmotic consolidation has been recognized as a potential pathway to quickly drain dredged sediments and highly compressible disturbed clay. However, its efficacy in consolidating sensitive undisturbed soft clays found in the Nordic regions are not present. Even before initiating these techniques in the field, laboratory assessment of the electro-osmotic assisted drainage rate, consolidation parameters of the clay and corrosion potential of the electrodes are essential information for engineers. This laboratory study investigates the effect of voltage (10, 20, and 30 V) on the consolidation parameters of undisturbed soft clays using only electro-osmosis and then a coupled approach (incremental loading with intermittent current). The efficacy of the exit hydraulic gradient (in m/s) increased by three-to-four orders regardless of the voltage used in the case of only electro-osmosis assisted consolidation. The electro-osmosis assisted consolidation allowed for consolidation up to 30% at in situ stresses (12–15 kPa) and within 2 h. Such rapid consolidation contrasts with 47% consolidation achieved when preloading is applied even at 1000 kPa, which in field would take place in months. When the coupled approach was utilized, even at 50 kPa of applied stress the consolidation improved by 30% even at 10 V. The coupled approach lowers the corrosion potential to negligible levels (≤0.2% by weight).