LABORATORY INVESTIGATION ON ELECTRO OSMOSIS PROPERTIES OF SINGAPORE MARINE CLAY

BO MYINT WIN, V. CHOA and X. Q. ZENG

ABSTRACT: In order to be able to design the electro-osmosis scheme, two major properties of clay, electro-osmosis permeability and coefficient of consolidation, need to be known. These properties can be measured in the laboratory by running the electro-osmosis consolidation test. This type of test is carried out with the help of modified triaxial apparatus in which the soil sample has an electric current applied, and its volumetric change accurately measured. It was found that the electro-osmosis permeability (k_e) of Singapore marine clay ranges between l0^-8 and l0^-9 m/v-s, whereas the electro- osmosis coefficient of consolidation (c_ve) varied between 0.17 and 2.81 m²/yr for tests under an electric potential gradient between 2 to 12 volts; c._ve increased with voltage applied. Physical and compressibility properties changes were noted after the electro-osmosis process. Gain in effective stress due to electro-osmosis was significant and magnitude of effective stress gain was directly proportional to the voltage applied. However vertical displacement was found to be smaller and significant magnitude of volume change was contributed from lateral deformation. This paper describes the test apparatus, and procedures and discusses the results from electro-osmosis tests, carried out on Singapore Marine Clay

Key words: coefficient of consolidation , compressibility , electro-osmosis , permeability , volume change (IGC: D4/D5 /E2)