荷载振幅对X形桩-筏复合地基动力响应特性影响的试验研究

Experimental study on load amplitude impact on dynamic response of XCC pile-raft composite foundation

基于大比例尺模型试验方法,开展砂土地基中X形桩-筏复合地基的动力特性试验研究;振动波型采用正弦波荷载,通过改变循环荷载的振幅,实测不同循环荷载下X形桩-筏复合地基的速度响应、桩身动应力响应以及动土压力响应随荷载振幅的变化规律,揭示X形桩-筏复合地基的动力响应机理。研究结果表明:随着地基深度的增加,桩-筏复合地基的速度响应逐渐衰减、桩身动应力大致呈波动性减小;随着荷载振幅的增加,速度响应、桩顶动应力响应以及动土压力响应均近似呈线性增加;碎石垫层具有良好的减震作用。

Based on large scale model test method,experimental study on dynamic response of cast-in-situ X‒shaped concrete(referred as XCC)pile-raft composite foundation embedded in sand was carried out.The sine wave load was used,and the amplitude of cyclic loads was changed.The velocity response of raft,dynamic stress response of pile,dynamic soil pressure response of XCC pile-raft composite foundation under cycle loads were measured.The dynamic response mechanism of the XCC pile-raft composite foundation was discussed.The results show that the vibration velocity of pile-raft composite foundation gradually decreases and the dynamic stress response of pile decreases approximately in a ware shape with the depth.The velocity response,dynamic stress response of pile top,and the dynamic soil pressure response nearly linearly increase with the increase of load amplitude.Gravel cushion layer has a good damping effect.