Lateral and cyclic responses of model piles in electrically treated clay

Abstract

An innovative technique to improve the capacity of piles installed in soft clayey soils using high-voltage electrokinetics was investigated in the present study. A largescale testing facility was established to execute the treatment and perform loading tests on the model piles. Eight steel pipe piles were installed in two identical cylinders filled with simulated marine sediment. Five electrically insulated electrodes were installed close to the piles to develop a non-uniform electric field in the test cylinder. Negative DC voltages of −20, −30 and −10 kV were applied in three phases for 33 days in the treatment cylinder. Lateral and cyclic lateral loading tests were performed, and the results were compared for both cylinders after each phase of treatment. The pile response was presented in terms of the experimental load–deflection curves. It was observed that the lateral capacity increased 81, 60 and 12% after the first, second and third treatment phases, respectively. The pile stiffnesses increased, and the displacements at the peak amplitude of the cyclic load decreased, due to the treatment. The improvement in the cyclic performance of the piles was evaluated in terms of the change of the soil degradation factors. The soil degradation factor increased 4·6, 14·6 and 2% after the first, second and third treatment phases, respectively.