负摩阻力作用下高速铁路桩基础承载特性研究

Research on the bearing capacity of high-speed railway pile foundations considering negative skin friction

针对受高速公路路基堆土影响的高速铁路桩基础,开展了桩基础承载特性研究。采用双线性土弹簧,建立了三维有限元模型,分析了考虑负摩阻力和不考虑负摩阻力的高铁桥墩在不同荷载及其组合下的结构响应。计算结果表明:考虑负摩阻力后,桩体侧壁以及桩底与土基之间并没有出现大变形,但是,将使桩基础在不受上部荷载作用时的竖向位移显著增加,并且桩体出现拉应力;桩基础受到上部荷载后,桩基础负摩阻力效应降低,桩体在该种状态下没有出现拉应力,但随着路基荷载的增加,拉应力有出现的趋势。

Aiming at the high-speed railway pile foundations affected by expressway subgrade, the research on bearing behavior of pile foundation is carried out.Using the bilinear soil spring 3D finite element model is established, the structural response of the high-speed railway bridge pier is analyzed under different loads and loads with or without the consideration of the negative skin friction.Calculation results show that the large deformation between the pile body and the soil foundation does not occur with the consideration of negative skin friction, but the vertical displacement significantly increased when the pile foundation is not affected by the upper loads, and the tensile stress appears. When the pile foundation is affected by the upper loads, the effect of negative skin friction will decrease, and then the tensile stress does not generate as the subgrade load increases, and the tensile stress will generate.