Pore pressure response of undrained two-way cyclic loading of silt

Abstract

A series of stress-controlled undrained two-way cyclic loading tests were performed on reconstituted samples of isotropically consolidated Keuper Marl silt (LL = 36%, PI = 19%) of various stress histories and stress levels. The series included cyclic loading with and without rest-periods, and resulted in either failure or non-failure of the sample during cyclic loading. Following a restperiod, non-failure samples were subject to further cyclic loading, Studies on the pore pressure response of normally consolidated samples indicated that permanent pore pressure developed steadily with the loading period, but the rate of development decreased as the loading period increased. A linear relationship was found to exist between the normalised permanent pressure rate and time, plotted on logarithmic scales