Undrained Creep Behavior of a Silty Clay in Triaxial Tests

A number of undrained triaxial creep tests were performed for remolded Hong Kong marine clay (HKMC). The tests performed include three types: (1) three single-load-staged undrained triaxial compression creep tests; (2) one multi-load-staged undrained triaxial compression creep test, and (3) one multi-load-staged undrained triaxial extension creep test. Based on the test results, the undrained creep stress-strain Behavior are investigated. It is found that the relationship of axial strain rate (ɛ˙_a) against time (logt) for the single-load-staged creep tests is nearly linear, and for different creep loads the slopes of lines are almost the same. In multi-staged creep test, however, the creep deformation of current step will be affected by the current deviator stress as well as the creep history in the previous step. The parameters, m and α, will not be a constant, but changes with the current deviator stress and stress history. Based on the test results, two equations are found to determine the parameters of m and α.