Abstract

Sensitive clay is a kind of clay, which loses its shear strength when it is subjected to cyclic loading. High-rise buildings, towers, bridges etc., founded on sensitive clays usually suffer from reduction of the safety factor during its life span. Cyclic loading on foundation of sensitive clay during the undrained period may lead to quick clay condition and a catastrophic failure of the structure. In the literature, governing parameters such as cyclic deviator stress, pore water pressure, axial strain, pre-consolidation pressure, confining stress, initial degree of saturation, water content, liquidity index and the number of cycles are divided into two categories and then presented as a function of sensitivity. Nevertheless the limited data available has restricted the use of empirical formulae. It is of interest to note that sensitive clay's shear strength increases due to consolidation and decreases due to cyclic load. In this case, the pre-consolidation pressure plays the role of governing parameter. In this investigation, the experimental results available at Concordia University as well as the data available in literature will be used to evaluate the empirical formulae and models. The governing parameters will be evaluated on this basis. Based on this analysis, a procedure to assist practicing engineers in designing foundation on sensitive clay is proposed.