刚性桩复合地基模型在拟动力试验下的桩身反应研究

随着刚性桩复合地基在土木工程中的广泛应用,其抗震性能越来越受到人们的关注,而复合地基中桩身动力响应是确定其抗震能力的关键。为此依据相似理论,设计制作出一套主要由钢制砂箱、砂土以及比例为1∶10的3×3群桩模型组成的试验装置。将装置置于伺服加载系统下进行拟动力试验,按照相关规范输入地震波加速度时程并施加上部荷载,获得不同工况下刚性桩复合地基桩身应力应变响应结果。试验结果表明:①各桩最大剪力均发生在桩顶处,对比不同位置桩的剪力,角桩剪力响应值最大;②各桩最大弯矩值均发生在Z/L=0.3~0.43的区间内,对比不同位置桩的弯矩,角桩的桩身弯矩响应值大于边中桩,而边中桩又大于中心桩;③保持地震波的加速度峰值不变,增大施加的上部荷载,剪力和弯矩响应值会有比增大加速度峰值更大的增加幅度。

Study on Pile Response of Rigid Pile Composite Foundation Model Under Quasi-dynamic Test

With the wide application of rigid pile composite foundation in civil engineering,people pay more and more attention to its seismic performance,and the dynamic response of pile in composite foundation is the key to determine its seismic capacity.Based on the similitude theory,a set of test equipment consisting of steel sand box,sand soil and 3×3 pile group model with a scale of 110 was designed and manufactured.The device was placed under the servo loading system for quasi-dynamic test,and the time history of seismic wave acceleration was input according to the specification and the upper load was applied to obtain the stress-strain response results of rigid pile composite foundation under different working conditions.The test results show that①the maximum shear force of each pile occurs at the top of the pile.②the maximum bending moment value of each pile occurs in the interval of Z/l-0.3-0.43;bending moment of pile at different positions the bending moment response value of corner pile is greater than that of edgewise pile,and edgewise pile is greater than that of central pile;③keeping the peak acceleration of seismic waves unchanged,and increasing the applied upper load,the response values of shear force and bending moment will increase more than when the peak acceleration is increased.