地铁盾构隧道磨桩掘进参数优化及最优加固圈厚度研究
Investigation on optimization of driving parameters and optimal thickness of reinforcement ring for grinding pile in metro shield tunnel
严飞 1李建旺 2阿尔曼·赛力克 3郭建伟 2伍天华 3徐辉3
作者信息
- 1. 中铁十五局集团有限公司,上海 200070;北京科技大学土木与资源工程学院,北京 100083
- 2. 中铁十五局集团有限公司,上海 200070;中铁十五局集团城市轨道交通工程有限公司,河南洛阳 471002
- 3. 北京科技大学土木与资源工程学院,北京 100083
- 折叠
摘要
为解决盾构隧道磨桩施工期间掘进和加固参数的确定存在不确定性和主观性问题,文章以苏州地铁 6号线区间隧道下穿既有车站时需磨除大直径桩基为工程背景,运用FLAC 3D数值模拟和现场试验监测方法,研究并优化盾构隧道磨桩掘进参数以及MJS加固圈的厚度取值.研究结果表明:盾构隧道磨除既有桩基施工过程中,掌子面(土仓)压力和壁后注浆压力宜分别控制在0.2～0.3 MPa和0.5 MPa左右,注浆层厚度不得低于建筑间隙厚度,必须保证壁后填充率大于100%且宜控制在200%左右.采用MJS工法桩加固能够减少盾构施工对周围土层及既有桩的扰动,保证既有桩的固有承载性能,最优加固圈厚度宜控制在1.6D～1.8D之间.现场监测结果与数值模拟结果吻合,可验证优化后的参数具有可行性,相关研究可为类似磨桩工程提供参考和借鉴.
Abstract
To solve the issues of uncertainty and subjectivity in the determination of driving and reinforcement parameters during the construction of shield tunnels,against the background that the large-diameter pile foundation needs to be removed when the section tunnel of Suzhou metro line 6 passes through the existing station,this article studies and optimizes the excavation parameters of the shield tunnel grinding pile and the thickness of the MJS reinforcement ring with the help of FLAC 3D numerical simulation and field test monitoring methods.The results show that during the construction of the shield tunnel to remove the existing pile foundation,the pressure of the tunnel face or soil bin and the grouting pressure behind the wall should be controlled at about 0.2～0.3 MPa and 0.5 MPa respectively,the thickness of the grouting layer shall not be less than the thickness of the building gap,and the filling rate behind the wall must be guaranteed to be greater than 100%,and should be controlled at around 200%.The use of MJS method for pile reinforcement could better reduce the disturbance of shield construction to the surrounding soil layers and existing piles,ensure the inherent bearing performance of existing piles,and the optimal reinforcement ring thickness should be controlled between 1.6D～1.8D.The field monitoring results are in good agreement with the numerical simulation results,which could verify the feasibility of the optimized parameters.The relevant research could provide reference value for similar pile grinding projects.
关键词
地铁/盾构隧道/磨桩/参数优化/MJS加固/FLAC/3D模拟Key words
metro/shield tunneling/grinding pile/parameter optimization/MJS reinforcement/FLAC 3D simulation引用本文复制引用
基金项目
国家重点研发计划(2023YFC3707804)
出版年
2024
NETL
NSTL
万方数据