Laboratory investigation of electro-osmosis effects in saturated dredger fill—a comparison with the stack preloading

Abstract

ABSTRACTA set of unconventional electro-osmosis (EO) experiments using intermittent current was conducted on dredger fill samples from a land reclamation site at Liaoning Coast in China. This study focused on the quantitative evaluation of the use of EO to enhance the effect of surcharge preloading consolidation, thus improving the mechanical and physical properties of soil. The sand wells were used to avoid excessive consumption of electrical energy in the process of repeated seepage. A systematic comparative study on preloading combined with electro-osmotic consolidation shows that the EO coefficient decreases with water content. The increase in shear strength at a potential difference of 15 V combined with a loading of 2.67 kPa is approximately twice as high as that of preloading only, but the electrical power consumption is merely 23% more. Mercury injection tests and scanning electron microscopy images showed that the subsidence mechanism of Liaoning Bay soil is the change of macropores to mesopores. Furthermore, using the combined method of EO and preloading results in even treatment effects in different soil depths. Electrochemical reaction and economic benefit are further analyzed. All of these results indicate that combining preloading and EO ensures better performance than individual operation.