INFLUENCE OF DURATION OF SUCTION EQUALIZATION ON SUBSEQUENT SHEARING OF AN UNSATURATED SOIL

摘要

A series of direct shear tests were performed to investigate the influence of duration of suction equalization on subsequent shear behaviour of an expansive clay. Soil specimen was prepared at a high suction and then lowered to a smaller value under different durations of suction equalization. Test results show that shorter duration of suction equalization resulted in higher strength and more dilative behaviour during shearing. The influence of duration of suction equalization on shear behaviour is believed to be caused by the difference between suction in soil specimen and applied suction externally. Shorter duration of suction equalization resulted in smaller degree of saturation, leading to higher suction in soil specimen. The higher suction made the soil specimen to exhibit more dilative behaviour and higher strength. Therefore, it is vital to obtain suction equalization before shear.