考虑桩径比影响的陇东深厚黄土地基群桩模型试验研究

Model test of pile group on deep loess foundation in Longdong considering the influence of pile diameter ratio

针对陇东深厚黄土地基特性,设计了陇东深厚黄土地基群桩承载力试验模型,研究了桩径比的变化对群桩承载和变形特性的影响。结果表明,桩径比对承台沉降速率影响明显。初始阶段桩长对沉降的抑制作用发挥不大,随着桩间土塑性变形的发展,长桩优势凸显,其沉降基本等速率,而短桩控制变形速率的能力较差。长桩属于整体剪切破坏,而短桩属于局部剪切破坏。随着荷载的增加,长桩的沉降量显著增加,桩土相互作用显著减小,甚至发生滑移,桩基宣告失效。对于深厚黄土桩基工程,长桩能更好地控制桩基沉降。

According to the characteristics of deep loess foundation in Longdong,the experimental model of pile group bearing capacity of is designed.This paper studies the influence of pile diameter ratio on the bearing and deformation characteristics of pile groups.The results show that the influence of pile diameter ratio on the settlement rate of bearing platform is obvious.In the initial stage,the pile length has little effect on the settlement.With the development of plastic deformation of soil between piles,the advantage of long piles becomes obvious and its settlement rate is basically equal,but the ability of short pile to control the deformation rate is poor.For long pile it belongs to global shear failure,while for short pile it belongs to local shear failure.As the load continues to increase,the settlement of long pile increases significantly,the pile-soil interaction decreases significantly and even slips,and the pile foundation is declared invalid.For the deep loess pile foundation project,the long pile is better for the settlement control of pile group foundation.