Pore Pressure Response of Undrained Two-Way Cyclic Loading of Silt

Abstract

A series of stress -controlled undrained two-way cyclic loading tests wereperformed on reconstituted samples of isotropically con solidated Keuper Marl silt(LL = 36%, PI = 19%) of various stress histories and stress levels. The seriesincluded cyclic loading with and without rest-periods, and resulted in eitherfailure or non-failure .of the sample during cyclic loading. Following a restperiod,non-failure samples were subject to further cyclic loading. Studies on thepore pressure response of normall y consolidated samples indicated thatpermanent pore pres sure developed steadily with the loading period, but the rateof development decreased as the loadin g period increased. A linear relationshipwas found to exist between the normalised permanent pressure rate and time,plotted on logarithmic scales.