竖向-水平荷载共同作用下PCC桩荷载传递机理研究

Research on the Load Transfer Mechanism of PCC Pile under Vertical-horizontal Loads

以浙江杭千高速公路现场实际工程为依托,建立了PCC桩-桩周土-桩芯土有限元模型,采用现场试验结果验证了模型合理性。在此基础上,研究了竖向-水平荷载共同作用下PCC桩竖向荷载传递机理。研究结果表明,先期水平荷载的施加致使桩顶沉降增大,不同先期水平荷载的影响效果差别不大;先期水平荷载对桩侧土抗力和桩外侧摩阻力的影响在埋深约2/3范围内作用明显,迎土侧二者均随水平荷载增大而逐渐增大,背土侧二者均随水平荷载增大而逐渐减小,且水平荷载较大时桩顶背土侧附近出现零应力区;桩内侧摩阻力沿桩身近似呈L形分布,几乎不受水平荷载影响。

Based on field engineering project,the finite element model of PCC pile and inner soil is established.The model is verified by field test results,then the vertical load transfer mechanism of PCC pile under vertical horizontal load is studied.The results of the study show that the application of prehorizontal load causes the increase of pile＇s top settlement,and the additional settlement caused by different levels of the pre-horizontal load is not different significantly.The influence of the pre-horizontal load on the lateral soil resistance and the lateral friction resistance of the pile is obvious in the range of 2/3,and both of them are gradually increasing with the increase of pre-horizontal load at the side against the lateral load,when their values are gradually decreasing with the increase of horizontal load at the side along the lateral load,besides the zero stress zone will appear near the pile head when the horizontal load is large.The internal friction of pile is approximately L-shaped distributed along the pile shaft,which is almost unaffected by the pre-horizontal load.