Experimental Investigation of Foundations on Sensitive Clay Subjected to Cyclic Loading

Sensitive clay subjected to cyclic loading may experience gradual loss of its shear strength, which may lead to a significant reduction in its bearing capacity, excessive settlement, and perhaps catastrophic failure. This may be caused by the cyclic loading, which acts as a disturbing agent and a major cause for increasing pore-water pressure, leading to leaching of salt content and the failure of the card house structure of the sensitive clay. This paper presents the results of an experimental investigation on sensitive clays subjected to cyclic loadings under undrained and drained conditions. Tests were conducted to examine the effects of cyclic loading, deviator stress, load frequency, preconsolidation pressure, overconsolidation ratio, confining pressure, sensitivity, liquidity index, and degree of saturation on the shear strength of sensitive clay. Depending on the combined effect of governing parameters, the shear strength of the clay may significantly be reduced, and the clay may reach a liquefiable state. This study introduces the concept of a safe zone to examine existing foundation conditions or provide guidelines for the design of new foundations on sensitive clay.