Creep behavior of water-containing bedded shale

In this paper, the creep property of shales is examined from two viewpoints: one is bedding orientation and the other is the water content. To investigate these effects, uniaxial creep tests were carried out on water-containing bedded shales. The creep curves were continuously observed with different water contents and bedding orientations. The correlations of water content and bedding angle with the transient elastic modulus and transient creep rate were constructed. The effects of bedding angle and water content were incorporated into the creep parameters of Burgers creep model, and the microscopic mechanism of water effect was interpreted based on mineral compositions due to rock-water interaction. The results revealed that the shale with a higher bedding angle had a higher transient elastic modulus and a lower transient creep rate. A higher water content triggered a lower transient elastic modulus and a higher transient creep rate.