Stress-dilatancy of natural soft clay under an undrained creep condition

International audienceThe stress–dilatancy relationship is a key point to capture the evolution of both strains and excess pore pressure during an undrainedcreep of natural soft clay. This paper focuses on investigating the stress dilatancy of natural soft clay during an undrained creep. Undrainedtriaxial creep tests are performed on K0-consolidated and isotropically consolidated samples of a typical Chinese soft marine clay with differentstress levels. A unique stress–dilatancy curve is obtained from all test results. Several typical stress–dilatancy relations for soils are discussed,comparing them with experimental results. A common modification method for the stress dilatancy of sand is adopted and discussed for clay. Allcomparisons demonstrate that modified dilatancy equations can describe the stress–dilatancy relationship during an undrained creep. Themodified dilatancy equation with the inclination of a potential surface seems to better describe the whole trend, and is suitable for natural soft clay