Abstract:Self-made single blade screw anchor pile which was embedded soil pressure gauges was tested by uplift loading experiment. The variation of mounting torques, anchor's displacements and soil pressures on blade surface versus uplift loading under different embedded depths was recorded to analyse the relationship between installation torque, ultimate uplift bearing capacity and embedded depth ratios, and a preliminary inquiry was also made on the distribution regulation of soil pressure on helical blade surface. The results showed that, both of mounting torque and ultimate bearing capacity increased linearly with the buried depth ratio, and they were linearly independent to each other for the common influenced factors. In the pullout process, the increment of soil pressure on the surface of blade increased gradually from root to the edge, and the increment on the lower surface was far less than that of the upper one. The most of the area maintained the pressure constant except enlarged on few marginal area. The resultant force of two sides of blade increased with the loading, and the frictional resistance between pile and soil was parabolic developed. When the uplift displacement reacheed the limit ones of soil failure, the frictional resistance reached the peak value, and then decreased to zero. The bearing capacity of screw anchor pile could be calculated by the analysis of soil pressure on the blade surface.