Estimation Method of Frost Heaving for Chilled Gas Pipeline Buried in Frost Susceptible Soil

摘要

It has been known that chilled gas pipeline buried through a boundary between permafrost and non permafrost is likely to suffer bending deflection due to frost heave since the pipeline is hold tightly in permafrost whereas the other end in non permafrost is surrounded by growing frost bulb and is subjected to frost heave. For the frost heave estimation of structure buried in frost susceptible soil, various methods have been proposed so far. However, most of those require many parameters to explain this complicated phenomenon as a numerical model since the frost heave depends on freezing rate, permeability of the soil, amount of water migration and etc. The authors, then, propose to adopt Takashi’s equation for the frost heave estimation. Introducing only three parameters obtained through indoor experiment, Takashi’s equation relates the frost heave ratio with the overburden pressure at the freezing front and its freezing rate. In this paper, a practical estimation method of frost heave which combines Takashi’s equation and a beam on elastic foundation model is presented and numerical examples are shown. Introducing Takashi’s equation, numerical example demonstrates the possibility of frost heave prediction by this method with satisfactory accuracy for engineering design.