摘要
为减小新建隧道近距离侧穿施工对既有桥梁结构的扰动,结合现场监测数据建立三维有限元数值分析模型,研究施作旋喷桩对既有桥梁的影响规律.依托广州市电力盾构隧道工程,以直径、长度、桩-隧水平距离、桩重心与隧道轴线深度差为主要影响因素,采用正交试验分析旋喷桩不同设计参数对桥墩沉降、桩基水平位移和内力的影响.结果表明:旋喷桩施工会引起围岩应力上升,使得地层由单一的卸载沉降过程转变为先隆起后沉降变化路径,致使施工引起的桥墩沉降显著减小;旋喷法与隧道施工荷载组合会引起既有桩基产生较大的横向位移和弯矩;增大直径、长度或者减小桩-隧水平距离均可以显著提升旋喷桩控制桥墩沉降效果,但施工大直径长旋喷桩会引起桩基产生较大的横向位移和附加弯矩.采用旋喷桩作为隧道近接施工的隔离措施时,应该考虑高压旋喷法施工对围岩应力和位移状态的影响.
In order to reduce the disturbance of the new tunnel construction on the existing bridge structure,a three-dimensional finite element numerical analysis model is established based on the field monitoring data,and the influence of the jet grouting pile on the existing bridge is studied.Based on the power shield tunnel project in Guangzhou,the influence of different design parameters of jet grouting pile on pier settlement,horizontal displacement and internal force of pile foundation is analyzed by orthogonal test with diameter,length,horizontal distance between pile and tunnel,and depth difference between pile center and tunnel axis as the main influencing factors.The results show that the construction of jet grouting pile will cause the stress of surrounding rock to rise,which makes the stratum change from a single unloading settlement process to a change path of first uplift and then settlement,resulting in a significant decrease in the settlement of bridge piers caused by construction.The combination of jet grouting and tunnel construction load will cause large lateral displacement and bending moment of existing pile foundation.Increasing the diameter,length or reducing the horizontal distance between pile and tunnel can significantly improve the effect of jet grouting pile on controlling the settlement of pier,but the construction of large diameter and long jet grouting pile will cause large lateral displacement and additional bending moment of pile foundation.When the jet grouting pile is used as the isolation measure for the adjacent construction of the tunnel,the influence of the high-pressure jet grouting method on the stress and displacement state of the surrounding rock should be considered.
作者
庞国威
翁效林
侯乐乐
PANG Guowei;WENG Xiaolin;HOU Lele(Key Laboratory for Special Area Highway Engineering of Ministry of Education,Chang′an University,Xi′an 710064,China;School of Highway,Chang′an University,Xi′an 710064,China)
出处
《西安建筑科技大学学报(自然科学版)》
北大核心
2025年第4期563-572,共10页
Journal of Xi'an University of Architecture & Technology(Natural Science Edition)
关键词
盾构隧道
旋喷桩
数值计算
正交试验
shield tunnel
jet grouting pile
numerical calculation
orthogonal test
