An isotache model for frozen soil taking account the effect of creep on plastic yield pressure

Plastic yield pressure is a key factor influencing mechanical behavior of frozen soil. In this paper, an isotache model taking account the effect of creep on plastic yield pressure was modified to describe the mechanical behavior of frozen soil. A series K-0 compression tests after different creep time and at different temperature were carried out on a fine grained soil obtained from Qinghai-Tibet plateau. Based on analysis of the tested results, it was proved that the strain development of the tested frozen soil obeys the postulation of parallel lines in isotache model. Meanwhile, the development of plastic yield pressure with creep strain is inversely related to temperature, which can be reasonably described by exponential function deduced from the isotache model. The sharp strain increase of frozen soil can be captured by the isotache model when the surcharge loading exceeds the plastic yield pressure. After modifying the isotache model as temperature dependent, mechanical behavior of frozen soil at different temperature can be described reasonably, and the development of plastic yield pressure with creep strain and temperature can be calculated conveniently.