公路特长箱涵结构受力特性及施工方案分析  

Analysis on mechanical characteristics of soil-covered and over-long box culvert and construction scheme of jacking

作　　者：郭瑞[1] 冯忠居[2] 

机构地区：[1]陕西理工大学土木工程与建筑学院,陕西汉中723001 [2]长安大学公路学院,陕西西安710064

出　　处：《广西大学学报（自然科学版）》2018年第1期340-348,共9页Journal of Guangxi University（Natural Science Edition）

基　　金：陕西省自然科学基金重点资助项目(2013JM7016);陕西理工大学人才启动项目(2013JM7016)

摘　　要：为分析公路特长箱涵顶进施工中结构及涵顶覆土的力学作用特性,结合广东梅河高速公路工程实例,建立公路特长箱涵顶进施工三维有限元模型,对比分析不同顶进长度和减阻措施工况条件下箱涵结构及覆土的应力应变变化规律,并对公路特长箱涵顶进施工方案进行了总结。结果表明,在其他工况相同条件下,随着顶进长度增加,箱涵顶板和底板的应力应变呈"台阶"状变化趋势,腹板亦呈现相同变化趋势,涵顶覆土沉降量呈不断减小变化趋势;随着摩阻系数增大,箱涵结构应力应变亦随之增大,采用减阻措施箱涵的涵顶覆土沉降量比不采用减阻措施的小,且采用石蜡+机油混合物减阻效果更好。建议涵节设计长度宜为4~6 m,工作坑横截面宜设计为倒"梯形"坑壁且采用1∶0.8坡率,后背墙宜采用钢筋混凝土重力式结构。A 3 D finite element model on jacking of super-long box culvert was established by Marc finite element software and combined with a project in Guangdong province to analyze mechanical behaviors of box culvert structure and covered soil in the jacking with a super-long box culvert,and construction scheme of the jacking was put forward. The results show that, under the same conditions,with the increase of jacking length,the stress-strain relation of roof and bottom plates features ＂step＂shape,and so does that of side wall. And overlying settlement at the top of culvert decreases. With the increase of friction coefficient,stress and strain of culvert increase. Under drag reduction,settlement of the covered soil is less than that without drag reduction. It is more effective to reduce the resistance by adopting paraffin plus oil. It is suggested that design length of culvertsection is 4 - 6 m,that cross section of working pit is designed to be inverted trapezoid,and ratio of slope of pit wall is 1 ∶ 0. 8. Back wall should be designed as a reinforced concrete gravity structure.

关 键 词：道路工程 特长箱涵 数值模拟 结构与覆土 力学作用 

分 类 号：U449.82[建筑科学—桥梁与隧道工程]