The creep behavior of an expansive clay under undrained conditions is investigated considering the effects of freeze-thaw-drying-wetting (FTDW) cycles. Compacted specimens were subjected to 1, 4, and 10 FTDW treatments. Macroscopic changes were recorded and mercury intrusion porosimetry tests were conducted to reveal the expansive clay's structure evolution during the FTDW treatments. The undrained shear strength was first determined by the consolidated undrained shear tests for as-compacted specimens. Subsequently, saturated undrained creep tests under low confining pressure were performed at various deviator stress levels (D) to study the axial strain development with time for specimens subjected to different FTDW cycles (NFTDW). Experimental results show that 1) the macropores increase with the newly emerged peak at a diameter between 10 mu m to 20 mu m and micropores decrease after FTDW cycles; 2) the axial instantaneous strain (epsilon ai), creep strain (epsilon ac), and total strain (epsilon at) increase with FTDW cycles. The epsilon ai-D-NFTDW and epsilon at-D-NFTDW relationships of the specimens are distributed on a unique surface under a certain confining pressure level; 3) the axial strain rate decreases dramatically within the first 2,000 min and then remains nearly constant. Studies in this paper are valuable for advancing the understanding of the influences of environmental factors on the creep behavior of expansive clays.
