摘要
市政道路采用明挖法下穿既有铁路,对铁路采取便梁-支撑桩加固系统时,由于基坑开挖导致支撑桩失去较多的土体约束,系统的横向稳定成为危及铁路运营的重大安全隐患。以陕西省安康市某市政道路下穿安康东站货车疏解上行线为例,对便梁-支撑桩加固系统在明挖条件下的横向稳定性进行分析,对加强措施进行研究并通过数值仿真、监控量测等方法进行验证。结果表明:在不采取加强措施时,加固便梁的横向振幅超过了安全限值;采取钢筋混凝土系梁加强后,经数值模拟分析可降低横向振幅约57%,施工现场实测降低横向振幅约48%,且均在安全限值以内;继续增设钢斜撑,对进一步降低横向振幅有一定的作用,可作为应急措施。下穿道路工程的顺利实施,验证了本文所述方法具有良好的成效,能够为类似明挖条件下市政道路下穿铁路的加固系统设计施工提供参考和借鉴。
When the municipal road adopts the cut and cover method to pass through the existing railway,the transverse stability of the auxiliary beam-supporting pile reinforcement system becomes a major hidden danger to the railway operation due to the loss of soil constraint of the supporting pile caused by the excavation of the foundation pit.Taking a municipal road in Ankang City,Shaanxi Province undercrossing Ankang East Station freight car dredging upstream line as an example,the transverse stability of the auxiliary beam-supporting pile reinforcement system in the open excavation construction condition is analyzed,and the strengthening measures are studied and verified by numerical simulation and monitoring measurement.The results show that the transverse amplitude of the reinforced auxiliary beam exceeds the safety limit when no strengthening measures are taken.When reinforced concrete tie beam is adopted,the transverse amplitude of the auxiliary beam can be reduced by about 57%by numerical simulation analysis,and about 48%by site monitoring and measuring,which are all within the safety limit.Furthermore,the steel diagonal brace can be added to reduce the transverse amplitude slightly,which can be used as an emergency measure.The project of new municipal road undercrossing existing railway has been carried out smoothly,which proves that the method described in this paper has a remarkable effect.It can provide reference for the design and construction of the auxiliary beam-supporting pile reinforcement system of municipal road undercrossing railway under similar open excavation condition.
作者
卢裕杰
LU Yujie(China Railway Fifth Survey and Design Institute Group Co.Ltd.,Beijing 102600,China)
出处
《铁道建筑技术》
2023年第7期56-60,共5页
Railway Construction Technology
基金
中铁第五勘察设计院集团有限公司科技研发计划项目(T5Y2021-C17)。
关键词
明挖
便梁-支撑桩系统
横向稳定性
钢筋混凝土系梁
钢斜撑
cut and cover method
auxiliary beam-supporting pile system
transverse stability
reinforced concrete tie beam
steel diagonal brace
