Abstract:Under the combined action of climate warming and human activities, the upper limit of frozen soil layer is gradually moving down for many years. Based on a middle bridge on an expressway in Qinghai, the axial bearing capacities of its pile foundation are numerically simulated under the different upper limit position schemes of frozen soil layer. By comparing and analyzing the axial bearing capacity indexes of pile foundation calculated by simulation, the variation law of axial bearing capacity indexes of bridge pile foundation is obtained with the upper limit downshift of frozen soil layer. The achievements provide some reference for the design, construction and reinforcement of bridge pile foundation in frozen soil regions for many years.