Stress and deformation characteristics of ultra-long bored pile in deep soft soil area

Abstract

In view of the diverse geological conditions in China, ultra-long bored pile can effectively enhance the bearing capacity and stability of foundation. Due to the special geological condition in the Beijing-Tianjin-Hebei region, there are a large number of soft soil areas. Taking an elevated bridge in Xiongan-Daxing track construction project as an example, this paper uses finite difference method to study pile-soil interaction and failure mode of pile. With the increase of load, plastic failure occurs first at the top of the pile and then at the bottom of the pile. At the same time, the curve of the plastic failure zone of the soil layer presents a process of “gentle - rapid - gentle - steep rise”. When the load reaches a certain critical value, the plastic zone area changes abruptly. As the load increases, the funnel-like characteristics of the maximum and minimum principal stresses diminish, resulting in minimal stress difference throughout the soil layer.