端承型桩承载力离心模型试验中的粒径效应研究

Particle Size Effects on the Centrifuge Bearing Capacity Tests of the End Bearing Pile

利用modeling of models的方法研究端承型桩承载力离心模型试验中的粒径效应。在模拟同一原型时,不同桩径的模型桩,桩身压缩性及桩长均不同,导致侧摩阻力发挥机理及程度不同,本文分别探讨了桩端阻力,侧摩阻力及承载力(桩顶荷载)的粒径效应对承载机理和承载特性的影响。结果表明,桩端阻力的粒径效应作用规律与浅基础一致,可以借用浅基础的粒径效应定量评价方法评价端承桩承载力离心模型试验中的粒径效应。侧摩阻力的粒径效应比桩端阻力的粒径效应显著。由于侧摩阻力的影响,相同条件下承载力的粒径效应比桩端阻力有所增强。对于极限桩端阻力和极限承载力,粒径效应均随长径比的增加而减弱。

The particle size effects on the centrifuge bearing capacity test of the end bearing pile were studied by modeling of models. For the same prototype, because the different model piles had different length and compressibility, the mobilization of the shaft resistance was different. In this paper, the influence of the particle size effec on the end resistance, the shaft resistance and the total pile resistance were discussed respectively. The test results showed that the rule of particle size effects on the end resistance was the same as the shallow foundation, and the index evaluating the particle size effects on the shallow foundation could be used to assess the influence on the end resistance. The particle size effect on the shaft resistance was more obvious than the end resistance. And because of the shaft resistance, the particle size effect on the total pile resistance was also more marked than the end resistance in the same condition. For both the end resistance and the total pile resistance, the particle size effect decreased as the slender ratio increased.