杂填土地基中螺杆桩竖向承载特性研究

In order to study the vertical bearing characteristics of screw piles in miscellaneous soil foundation, the pile-soil occlusion mechanism was analyzed based on the limit equilibrium theory. Moreover, the equivalent lateral resistance increase coefficient of the threaded section was obtained by combining the interaction between pile and soil, based on which the calculation formula of the vertical bearing capacity of a single pile was established. The scale model tests of screw pile single pile in miscellaneous fill soil foundation were carried out. The results show that the load-settlement curve of the screw pile undergoes three stages including elastic, elastoplastic and plastic failure under the action of vertical load. According to the distribution law of the axial force of the pile and the equivalent lateral friction resistance of the pile side along the depth obtained from the model test, the equivalent lateral friction resistance of the threaded section is greatly improved for the straight rod section in general. When the ultimate bearing capacity is reached, the equivalent lateral resistance expansion coefficient obtained by the test is basically consistent with the theoretical analysis results.