Creep behavior of unsaturated reticulate red clay under matric suction

In order to study unsaturated creep behaviors of reticulate red clay under matric suction, a series of isotropic creep tests with different matric suction level were carried out by using Geotechnical Digital Systems (GDS) unsaturated apparatus. Results indicate that creep strain caused by matric suction increases with the increasing of matric suction level and tends to certain stability over time. Based on the analyses of test results, a creep model for the unsaturated reticulate red clay under matric suction was established to predict the creep strain caused by matric suction. In the model, a new parameter M (matric suction level) was defined as a ratio of the matric suction to the net confining pressure, a hyperbolic function was adopted for the description of the strain-time relationship and an exponential function was employed for the strain-M relationship. Predicted results are in good agreement with the test results shows that the model can reasonably simulate the effects of matric suction on creep properties of unsaturated reticulate red clay.