the effects of drainage conditions on the cyclic deformation characteristics of over consolidated clayey soil

Drainage conditions and consolidation states can affect the deformation behaviour of clayey soil under cyclic loading. a series of cyclic triaxial tests were carried out on normally and over consolidated kaolin under both undrained (ud) and partially drained (pd) conditions. the effects of drainage conditions on the strain accumulation, excess pore water pressure (epwp) and resilient modulus (mr) of the soil are analysed under different over consolidation ratios and cyclic stress amplitudes. the results indicate that greater axial strain may accumulate under pd condition than under ud condition if the cyclic stress is small. with the increase of over consolidation ratio, lateral deformation in soils under pd condition is similar to those under ud condition. meanwhile, a large axial strain could accumulate with a small amount accumulation in epwp under ud condition or in volumetric strain under pd condition. the mr of soil decreases as epwp increases under ud condition or as volumetric strain increases under pd condition. for the over consolidated soil, mr could degrade significantly with little accumulation in epwp under ud condition or in volumetric strain under pd condition. for example, under an over consolidation ratio of 5 and ud condition, mr degrades about 20–55% with epwp accumulation of 2–13 kpa. © 2022, iran university of science and technology.