Experimental Research On The Effect Of Electricity Design To Electro-osmotic Consolidation Of Soft Clay

Electro-osmotic consolidation with a high dewatering speed and an independent electric permeability, is suitable for fine-grained clays, such as dredger fill. However, an extensive literature suggests that there are several deficiencies, as high energy consumption, corrosion electrode, inefficiency at later stage, which block the development of electro-osmosis in practice. Therefore, researches were implemented to study how to overcome those shortages better from the perspective of electricity scheme.To clarify the dispute of efficiency about polarity reversal and current intermittent in improving the effect of electro-osmosis, following studies were conducted:For polarity reversal, researches focused on two parts:theory and experiment. In theoretic part, on the basis of Esrig’s assumptions, evolution of pore water pressure with time in polarity reversal was revealed, which proved the efficiency of electro-osmosis theoretically. In experimental part,4contrastive tests with different reversal periods were conducted. The results shows that:the polarity reversal technique was confirmed to contribute to the uniformity of soil properties and deformation; while in comparison of drainage and shear strength, the polarity reversal was not superior to normal electro-osmotic. The main reason is that this technique breaks the acid-base equilibrium in the soil, which leads to the rapid rise in the loss of contact potential and finally reduces the efficiency of electro-osmosis. At last, the conclusion and suggestion that polarity reversal is not recommended in electro-osmosis was given.In current intermittent,7contrastive tests with different on-off time were conducted. Test data shows that, when power period was set from1to4hours and on-off time ratio was set about2.0, the corrosion of electrodes alleviated significantly, and the efficiency improved dramatically. However, the separation of the soil-electrodes interface aggravated by current intermittent.For improving electricity design scheme, design program about the parameters which is an important part in electricity scheme was proposed. Detailed design methods about some parameters like the volume of dewatering and electric permeability were given, while the ranges of some other parameters without clear design method were provided referring to certain famous electro-osmotic cases.The studies on electro-osmosis from the perspective of electricity scheme was conducted for the first time in the thesis. The present work would be useful to promote the application and research of electro-osmosis.