Numerical analysis of vertical bearing capacity of bored screw pile in permafrost region

Bored screw pile in permafrost region is a new type of pile, and its vertical bearing characteristics have a great value for its popularization and application. The numerical method is verified based on indoor model test, and its bearing capacity composition mode is studied by numerical simulation, and compared with the widely used common bored pile. Finally, the estimation method of single-pile bearing capacity of the bored screw pile in permafrost region is put forward. The research shows that 90% of the bearing capacity of the bored screw pile in permafrost region comes from the mechanical occlusion between pile side concrete and permafrost, the shear strength of permafrost determines the bearing capacity of pile foundation, and the seasonal active layer has little influence on its bearing capacity, so the bearing capacity of pile body is stable all the year round. In permafrost regions, the equivalent friction calculated by axial force is far greater than the freezing force between conventional cast-in-place pile and frozen soil when the side threads of bored cast-in-place pile occlude with soil. When the pile reaches the ultimate bearing capacity, the plastic zone of the pile side is connected, and the soil around the pile is shearing. It can effectively estimate the design value of the bearing capacity of a single pile in engineering practice by improved formula to calculate the vertical bearing capacity of a single pile.