摘要
从公路交通沉管隧道的空间、重量和构造方面论述主结构优化的方法。讨论了行车孔净空确认原则;提出了隧道纵坡、管节长度、平曲线半径,以及预制段以直代曲折线长度引起的管节接头扭转角与断面加宽量的公式;揭示了重量设计参数与主结构尺寸的动态关联;分析了钢筋量的组成与比例及其主要控制荷载。以双向八车道、两孔一管廊、100 km/h时速大断面沉管为例,比较了不同规范、保护层厚度或允许计算裂缝宽度对钢筋用量的影响,定量研究了优化措施及组合对主要工程量的影响。主要结论:1)空间与重量需要同步优化;2)设计时速大,平曲线半径大,管节接头扭转效应可忽略;但平曲线对断面加宽量的影响不容忽视,需平衡永久结构工程量的减少与施工临时措施的增加,研究以直代曲的直线段长度合理取值;3)我国水上船舶与设备的发展使得沉管有可能始终处于被助浮状态,有条件时管节可设计成自带负浮力;4)沉管主结构形式优化时宜由复杂变简单,谨慎考虑顶板大倒角或外包防水层或防水底钢板的使用。
The optimization method of main structure of highway traffic immersed tunnel was discussed from the aspects of space,weight and structure.The principle of determining traffic bore clearance was discussed;the formula of torsional angle of element joint and additional width of bored area,resulted from tunnel longitudinal slope,element length,plane curvature,and straight-section-prefabrication-length,were derived;the interlink between the weight design factors and the main structure size were unveiled;the rebar amount constitutions,the ratios,and the main control load were analyzed.Taking the example of large cross-section immersed tunnel of dual-way-eight-lanes,two-traffic-bores-one-gallery and 100 km/h design speed,the influence of varied code,cover thicknesses,and allowable crack width on the amount of rebar was compared,and the impact of optimization measures and combination on main construction quantities was quantitatively studied.Main conclusions:1)space and weight shall be optimized simultaneously;2)with high design speed and large plane curve radius,the torsion effect of element joint can be ignored,however,the influence of plane curve on sectionn widening can not be ignored.It is necessary to balance the reduction of permanent structure quantity and the increase of temporary construction measures,and study the reasonable value of straight line section length with straight instead of curve;3)with the development of China's marine vessels and equipment,the immersed tube may always be in the state of being assisted to float.When conditions permit,the pipe joint can be designed with its own negative buoyancy;4)when optimizing the main structural form of the immersed tube,it should be changed from complex to simple,and the use of large chamfering of the roof or the use of waterproof layer or waterproof bottom steel plate should be carefully considered.
作者
林巍
田英辉
刘凌锋
邹威
刘孟源
陈猛
LIN Wei;TIAN Ying-hui;LIU Ling-feng;ZOU Wei;LIU Meng-yuan;CHEN Meng(CCCC Highway Consultants Co.,Ltd.,Beijing 100088,China;Tianjin University,Tianjin 300072,China;CCCC-FHDI Engineering Co.,Ltd.,Guangzhou,Guangdong 510230,China;CCCC Fourth Harbor Engineering Co.,Ltd.,Guangzhou,Guangdong 510290,China)
出处
《中国港湾建设》
2020年第10期28-35,共8页
China Harbour Engineering
关键词
沉管隧道
双向八车道
主结构
设计优化
immersed tunnel
dual-ways-eight-lanes
main structure
design optimization
