Experimental Study And Numerical Analysis Of Squeezed Branch Pile Foundation Of Power Transmission Tower

At present, the foundation of power transmission line is generally used in ordinary equal diameter reinforced concrete bored pile. This type of pile bears load mainly based on the lateral frictional resistance, so that the uplift and compressive bearing capacity is relatively poor. But the squeezed branch pile can improve the bearing capacity through special bearing plate, compared with the ordinary diameter filling pile foundation, the application of branch pile can not only reduce the pile diameter and length effectively, but save material quantity greatly and cut down the engineering cost, which has greater energy-saving benifits. If this new type of pile foundation can be used in power transmission line engineering widely, it will be of great economic significance.In this paper, in view of the Yangzhou Jiangsu soft soil region, the load bearing capacity and mechanical mechanism of squeezed branch pile under different load conditions are studied comprehensively and systematically based on the UHV AC power transmission line engineering of Huainan~Nanjing~Shanghai. including the following aspects:Firstly, the vertical compression and uplift bearing capacity of branch pile and pile group are obtained, and the effect coefficient of pile group is calculated, which provide basis for the first application of branch pile in the UHV AC power transmission line engineering.Then, the calculation formula of vertical bearing capacity of branch pile which is enforceable to the foundation of soft soil foundation is put forward based on the conclud of the design and calculation formula of the bearing capacity of branch pile in different regions and combined with the field test results.Finally, the stress mechanism and the influence factors of bearing deformation of squeezed branch singal pile under vertical load and squeezed branch pile group under combined vertical and horizontal loads are studied by means of the finite element method.The squeezed branch pile is a new foundation and its application in power transmission line is still in the stage of technology development. The research results can provide the technical support for the application of branch pile in the area of UHV AC power transmission line project, and it can provide reference for the application of branch pile foundation in the future similar soft soil area.