Undrained response of clays to varying strain rate

The undrained stress-deformation behavior of clays is significantly affected by the loading rate. Based on the observed experimental response, it is possible to model the strain rate response of clays as an apparent overconsolidated clay response. In this work, we have quantitatively determined the change in the overconsolidation ratio (OCR) due to a change in the strain rate. Our results show that the shear strength response and the excess pore water pressure response at the peak stress provide quantitatively similar magnitudes of change in the OCR with increasing strain rate. This finding holds true for both normally and overconsolidated clays. This suggests that the relationship between strain rate and change in the OCR can be considered as an inherent material characteristic and is quantifiable. A relationship between the change in the OCR and change in the strain rate is described.