过渡段地基加固作用对桥台桩工作性状的影响分析

发布时间：2018-02-09 21:06

本文关键词： 软土 CFG桩间距桥台桩工作性状离心机试验　出处：《中南大学学报(自然科学版)》2017年03期 　论文类型：期刊论文

【摘要】：为研究过渡段地基加固作用(桩间距为3d,4d,5d和6d,d为CFG桩径)对邻近桥台桩工作性状的影响,进行离心模型试验及三维数值模拟。研究结果表明:过渡段地基加固作用对桥台桩受力变形影响表现为在竖向上利用CFG桩荷载深层传递作用改变软土地基沉降变形特性,在水平方向上CFG桩对软土的侧向流动起显著阻拦作用;随着CFG桩间距增大,受负摩阻力作用的桥台桩中性点位置下移,最大轴力增大,桩端阻力随之增大;桩身弯矩最大值随CFG桩间距增加而增大,其位置(最危险截面)从桩长1/2处逐渐转移至桩顶;桩身剪力分布大致呈"反S"型,2处拐点分别位于土层界面及CFG桩端平面,且随着CFG桩间距增加,土层界面处桩身剪力增大而CFG桩端平面处剪力减小;桥台桩水平位移随桩间距增加以一固定点呈旋转式增大,桩身挠曲也越明显,而桥台转角及水平位移随桩间距近似线性增加;与天然地基相比,CFG桩在一定程度上限制了路基荷载下土体蠕变特性的发挥。
[Abstract]:In order to study the effect of foundation reinforcement in transition section (the spacing of piles is 3 d ~ 4 d ~ 5 d and 6 d ~ (d) is CFG diameter) on the working behavior of adjacent abutment piles, Centrifuge model test and 3D numerical simulation are carried out. The results show that the effect of foundation reinforcement in transition section on the deformation of abutment pile is to change the settlement and deformation characteristics of soft ground by using the deep load transfer of CFG pile in vertical direction. In horizontal direction, CFG pile has a significant effect on the lateral flow of soft soil, and with the increase of CFG pile spacing, the neutral point of abutment pile subjected to negative frictional resistance moves down, the maximum axial force increases, and the pile tip resistance increases. The maximum bending moment of pile increases with the increase of CFG pile spacing, and its position (the most dangerous section) is gradually transferred from the pile length 1/2 to the pile top, and the shear force distribution of the pile is approximately "anti-S" type and 2 inflection points are located at the soil interface and the CFG pile end plane, respectively. With the increase of CFG pile spacing, the shear force of pile body increases at the interface of soil layer and the shear force decreases at the end plane of CFG pile, and the horizontal displacement of abutment pile increases with the increase of pile spacing by a fixed point, and the deflection of pile body becomes more obvious. The angle and horizontal displacement of abutment increase linearly with the spacing of pile, and CFG pile restricts the creep property of soil under subgrade load to some extent.
【作者单位】：西南交通大学土木工程学院;西南交通大学高速铁路线路工程教育部重点试验室;
【基金】：铁道部科技研究开发计划项目(2010G003-F)~~
【分类号】：U443.15

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