水平循环荷载作用下单桩桩顶位移变化模型试验研究

Model test of pile-top displacement variation under effect of horizontal cyclic load

为了探究海上桩基础在长期受到水平循环荷载作用下的变形规律,选取典型的中砂作为试验土体,开展砂土中单桩水平荷载作用下的模型试验。获得了高次循环荷载下不同加载力及不同频率作用下的桩顶位移循环弱化的变化规律。试验结果表明:循环次数及加载力对桩顶位移变化影响显著,在水平循环荷载作用下,相同频率,加载力越大位移越大;而频率的改变对桩顶位移的影响不大;桩顶滞回圈的变化主要集中在前1万次并随后达到桩土相对稳定状态。研究成果为保证海上桩基的可靠性提供了具有价值的参考。

To explore the deformation law of offshore pile foundation under long - term horizontal circulat- ing load, the paper chose medium sand as test soil and carried out model test under effect of horizontal circulating load, and got the circulation weakening law of pile top displacement cycle under effect of dif- ferent load forces and frequencies of high order circulating load. The results show that the impact of cyclic times and loading forces on displacement variation is obvious. When the frequency is not changed, the more the loading force, the more is its displacement under effect of horizontal circulating load. The change of frequency has little influence on pile - top displacement. The change of hysteresis loop of pile top mainly occurs in the first 10,000 rounds of cyclic loading and then gets stable. The results can provide valuable reference for ensuring the reliability of offshore pile foundation.