Evaluation of the risk of sudden failure of a cohesive soil subjected to cyclic loading

This paper presents a proposed methodology to evaluate the risk of sudden failure experienced by a soft cohesive soil when acted upon by combined static and dynamic loading. The research is based on the results of a comprehensive experimental study in which 155 cyclic simple shear tests were performed on undisturbed specimens recovered at the port of Barcelona, Spain. The proposed experimental program is described in detail in addition to the systematic process of analysis to properly study and interpret the results obtained for samples subjected to cyclic loading. In general, the results indicate that the combination of monotonic and cyclic stresses governs pore water pressure generation, the pore water pressure generated during cyclic loading controls the risk of sudden failure, and by means of simple correlations among the stiffness modulus, the effective stresses, the cyclic strains and the number of cycles, it is possible to combine families of curves to allow for an evaluation of the risk of sudden failure.