NONLINEAR ANALYSIS FOR FROST-HEAVING FORCE OF LAND BRIDGES ON QING-TIBET RAILWAY IN COLD REGIONS

ABSTRACT A mathematical mechanical model and the governing differential equations of the coupled problem of temperature, moisture migrating, and stress fields with phase change, are first derived from the theory of heat transfer, the theory of moisture migration, and frozen soil mechanics. Then the finite element formulas of this problem are obtained by using Galerkin's method. Using the finite element formulas, a nonlinear analysis for the frost-heaving process of the land bridge in the next 20 years is made. The calculated results show that only soil at the bottom of the pile generates plastic deformation, and the deformation is quite small; therefore, the studied land bridge is safe.