水平循环荷载作用下群桩与软粘土相互作用离心模型试验研究

Centrifuge modeling of pile group response due to lateral cyclic loading in soft clay

桩基是水工构造物常用的地基处理方式之一,在国内外水运工程建设中均有应用。在波浪、船舶等循环荷载条件下,桩基和软粘土之间的相互作用,易发生软土强度弱化、桩基变形位移,带来工程危害。为解决这种情况,应从水平循环荷载作用下桩和饱和软粘土之间的作用机理着手开展研究。文章通过离心机模型试验,研究了水平循环荷载作用下饱和软粘土与高承台群桩基础的相互作用。试验结果显示,在每个加载卸载循环过程中,随着施加荷载值的增大,引起桩基的最大位移和残余位移同时增加。每次加卸荷循环后,桩体内均产生残余弯曲应变。群桩的前排桩产生的弯曲应变值是后排桩的3.2倍。

Piles are commonly used to support hydraulic structures in offshore engineering worldwide. Due to cyclic loading resulting from waves and ships,strength of soft soil near pile foundation may be weakened. Thus,permanent deformation may be induced in the existing pile foundations. The interaction between piles and saturated soft clay under horizontal cyclic loading should be studied. The centrifuge model tests are conducted to investigate the interaction mechanism between saturated soft clay and pile foundation due to horizontal cyclic loading. It was found from these model tests that the measured maximum and residual displacements of piles increase with the increase in the applied horizontal load. The residual bending strain is observed in the pile group after each loading-unloading cycle. The measured bending strains in the front pile are about 3. 2 times of those observed in the rear pile.