Experimental Study on Working Behavior of Vertically Loaded Screw-shaft Pile

The working behavior of the screw-shaft pile is influenced by various factors, among which the screw pitch and the screw length are two key factors. To study the progressive developing law of bearing capacity and soil deformation around vertical compression screw-shaft pile under different conditions, a model test based on digital image correlation deformation measurement is carried out, and the reliability of the model test is preliminarily verified by the field test results. The research reveals the influence law of the screw pitch and the screw length on the ultimate bearing capacity of the screw-shaft pile, and the empirical expression of normalized screw pitch diameter ratio factor and screw length ratio factor is established with reasonable values under the test condition. The distribution law of soil displacement field around the shaft section, screw section, and pile tip is concluded into different settlement stages, and the failure mode of soil around the screw-shaft pile with different pile type parameters is also proposed. The research results provide an experimental basis for the optimization of designing parameters and the establishment of the ultimate bearing capacity calculation theory of the screw-shaft pile.