Microstructural Analysis of Creep Behavior in Soft Clays during Cyclic Loading and Unloading

The present study investigated the evolution of the time-dependent behavior of remolded samples of Indian black cotton soil for different loading-unloading-reloading cycles in oedometer conditions. The microstructural analysis was carried out to evaluate the parameters such as particle rearrangement and pore size reduction that are responsible for creep at different time periods. It was observed that micropores existed in large numbers, and the number of pores decreased rapidly with an increase in pore size. The number of pores was found to decrease by 20–30% and 85–90% at the intermediate and final stages of the creep test, respectively. Additionally, it was noted that although small pores and mesopores were less in number, they were significant in pore area calculations. The reduction in pore areas for the intermediate and final stages was found to be in the range of 40–50% and 40–60%, respectively, as there were large proportions of micropores that compressed without influencing the overall pore area. The percentage of vertically aligned particles reduced from 21 to 15% at the end of the test. This observation is attributed to the particle rearrangement and reduction in pore sizes that occurred during the test.