在机加载条件下桩承式路堤离心模型试验设计

Design of In-flight Centrifuge Model Test for Piled Embankments

现有桩承式加筋路堤离心模拟技术存在诸多简化,忽略了模型应力历史的相似性。充分考虑几何布桩、材料特性、荷载及应力历史的相似性,优化设计了高重力场在机固结、插桩与路堤堆载的桩承式路堤离心模型试验方案。提出了对应在机加载过程的数值模拟方法,并分别建立了对应模型尺度和原型尺度的桩承式路堤单桩有限元模型。对比分析表明,模型尺度与原型尺度数值模型的桩土沉降曲线、荷载分担规律、路堤与桩身荷载传递、超静孔压分布均吻合,验证了桩承式路堤离心模型相似设计的正确性与合理性。离心模型试验方案能够反映桩承式路堤的变形发展、土拱效应与荷载传递特性,为在机加载条件下桩承式路堤离心模型试验奠定了重要的先期研究基础。

The existing centrifugal simulation technology for piled embankments contains many simplifications and neglects the similarity of model stress history.Fully considering the similarity of geometric pile layout,material characteristics,loading and stress history,a centrifuge model test protocol for piled embankments with high gravity field in-flight consolidation,pile construction,and embankment loading was optimized and designed.A numerical simulation method corresponding to the in-flight loading process was proposed,and a single pile finite element model of piled embankments was established at the corresponding model scale and prototype scale,respectively.Comparative analysis shows that the pile-soil settlement curve,load sharing law,load transfer of embankments and pile shaft,and excess pore water pressure distribution of the model scale and prototype scale numerical models are consistent,verifying the correctness and rationality of the similarity design of centrifuge model of the piled embankments.The centrifuge modeling plan can reflect the deformation development,soil arching effect,and load transfer characteristics of piled embankments,laying an important preliminary research foundation for the centrifuge model test of piled embankments under in-flight loading conditions.