Age of Soils: A Measure of Creep History
Time-dependent behaviors of soils are critical for engineering design. Results of one-dimensional (1-D) constant rate of strain (CRS) tests on clays show that there is an existence of unique relationship between current stress and strain state for a given constant strain rate, irrespective to previous stress-strain-time history. In the present study, this relationship is employed to estimate the creep rate during the CRS test. It is found that the creep rate is consistently related to distance from current stress-strain state to the instant compression line, which is the creep void ratio or creep history, termed age of soils. Based on the creep rate as a function of creep strain or age of soils, the stress relaxation rate function is derived through the correspondence principle. Age contours are iso-creep rate lines defining the creep rate field in stress-strain space. Creep Balanced State equation states that CRS path will converge to a iso-creep rate line. This equation is used to determine the CRS path and quantify the rate effect on preconsolidation pressure. Age- and pressure-dependent secondary compression coefficients are incorporated in the above framework.
Guo, J. (2017). Age of Soils: A Measure of Creep History (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/24743