地铁桩基钢套管施工对邻近铁路框架桥纵向变形影响分析
Analysis of the impact of pile foundation steel casing construction on longitudinal deformation of adjacent railway frame bridge
尹超 1刘维正 2盛越 3黎欢 1王锋 2廖军1
作者信息
- 1. 中建五局土木工程有限公司,湖南长沙 410004
- 2. 中南大学土木工程学院,湖南长沙 410075
- 3. 长沙市建设工程质量安全监督站,湖南长沙 410023
- 折叠
摘要
地铁桩基钢套管近距离施工会引起既有运营铁路框架桥的附加应力和变形,文章依托长沙地铁 1号线北延线高架桥桩基近接既有铁路框架桥工程,基于Mindlin应力解和Pasternak地基梁,建立钢套管施工引起框架桥纵向变形的计算方法.结合实测数据对该方法的准确性进行验证,并分析桩径、地层弹性模量、相对净距及施工附加力对框架桥纵向变形的影响规律.结果表明:钢套管施工过程对周围土体的附加力主要包括土塞压力、套管侧径向压力和套管侧摩擦力,施工扰动主要源于钢套管的旋进过程;框架桥随钢套管施工深度的增加先隆起再逐渐沉降;套管侧摩擦力是框架桥变形的主要因素,径向压力对变形影响最小;纵向差异沉降与桩径成正比,与弹性模量和相对净距成反比;相对净距为框架桥变形的主要控制因素,在 4倍桩径范围外时变形逐渐趋于零.工程中可从增大弹性模量和相对净距,减小土塞压力、套管摩阻力和桩径的角度控制框架桥变形,研究结果可为类似工程的设计施工提供依据.
Abstract
The construction of metro pile foundation steel casing in proximity could cause additional stresses and deformations in the frame bridge of existing operating railway.Relying on the Changsha metro line 1 north extension viaduct pile foundation close to the frame bridge of existing railway,the calculation method of longitudinal deformation of the frame bridge caused by the construction of steel casing is established based on the Mindlin stress solution and the Pasternak foundation beam.The accuracy of the method is verified with measured data,and the influence principles of pile diameter,elastic modulus of the ground,relative clear distance and additional force of construction on the longitudinal deformation of the frame bridge are analyzed.The results show that:during the construction of steel casing,the additional forces on the surrounding soil mainly include soil plug pressure,radial pressure on the casing side and friction on the casing side,and the construction disturbance mainly originates from the rotary process of the steel casing;the frame bridge bulges and then gradually settles with the increase of the construction depth of the steel casing;the friction on the casing side is the main factor of the deformation of the frame bridge,and the radial pressure has the least influence on deformation;the longitudinal differential settlement is proportional to the pile diameter,and the elastic modulus and the relative clear distance are proportional to the pile diameter;the relative clear distance is the main control factor for the deformation of the frame bridge,and the deformation gradually tends to zero when it is outside the range of 4 times of the pile diameter.During the construction process,the deformation of the frame bridge can be controlled from the perspective of increasing the modulus of elasticity and relative clear distance,decreasing the soil plug pressure,casing resistance and pile diameter,and the research results could provide a basis for the design and construction of similar projects.
关键词
地铁/桩基/钢套管/近接施工/纵向变形/计算方法Key words
metro/pile foundation/steel casing/proximity construction/longitudinal deformation/calculation method引用本文复制引用
基金项目
湖南省建设科技计划项目(KY202108)
出版年
2024
NETL
NSTL
万方数据