H型桩基托换框架性能研究

Model Test of the Anti-sliding of Steel-tubed Column in the Pile Underpinning

某火车站地下通道部分需下穿某地下商业街,商业街有25根桩位于下穿段结构范围内,拟采用被动托换方式进行托换。与常见的'一梁托一桩'托换形式不同,此托换工程采用了H型框架空间托换形式。为了弄清原结构以及H型托换框架的力学性能,选取工程中最不利位置为分析对象,对其进行了1∶4的模型试验、理论分析及数值模拟。分析结果表明:此原结构中的钢管在托换过程中不会发生滑移,H型的托换框架能够在有效的控制结构变形基础上,良好地传递上部荷载至托换框架,施工选用工况二先截两侧,再截中间的截桩方法最优,此为实际托换工程提供重要的参考。

The tunnel of a railway station passes through an underground commercial street.The Passive pile underpinning will be taken to deal with the 25 piles of the street in the range of tunnel.H-frame is used in this pile underpinning,and this protect is different to the common underpinning form—'one beam to one pile'.In order to understand the mechanical property of the original structure and the H-pile underpinning frame.The weakest point is chosen as the studying object of the 1:4 model test,theoretical analysis and the finite element analysis.The result shows:in the original structure,the steel tube will not slip in the process of underpinning.The H-frame can effectively control the deformation of the structure,and transfer of the upper load to the underpinning frame,the second work condition is optimal,which cut two both sides piles first then cut the middle pile.It can be instructed with the experimental results.