悬索桥大型沉井排水下沉控制的关键问题分析  

Key Issues About Drainage Sinking Control of Large Caissons in Suspension Bridge

作　　者：穆保岗[1] 朱建民[2] 龚维明[1] 欧阳祖亮[3] 

机构地区：[1]东南大学土木工程学院,江苏南京210096 [2]南通大学交通学院,江苏南通226019 [3]中交第二公路工程局有限公司,陕西西安710065

出　　处：《中国公路学报》2013年第6期118-127,共10页China Journal of Highway and Transport

基　　金："十二五"交通运输重大科技专项项目(2011318494160);江苏省自然科学基金项目(BK20116140);江苏省高校优势学科建设工程项目

摘　　要：为了给悬索桥大型沉井的顺利排水下沉提供参考,针对大型沉井特点,分析了其与中小型沉井下沉控制方式的异同,结合南京长江第四大桥和马鞍山长江大桥2个大型沉井的工程实践,探讨了首次下沉高度、下沉可行性指标以及开挖方式等关键问题对大型沉井下沉的影响。结果表明:大型沉井的首次接高高度受地基承载力和沉井自重应力水平的双重制约,采用荷载板试验结果来评估接高期的变形过于保守;由于荷载模式和参数取值的偏差,使传统的下沉可行性指标适用程度降低;排水下沉初期为受力最不利阶段,沉井排水下沉的开挖方式必须考虑沉井结构的抗弯刚度。In order to provide guidance for the drainage sinking of large caissons in suspension bridge, with the characteristics of large caissons considered, the similarities and differences between large caissons and small caissons were analyzed. Based on two practical projects, caissons of Nanjing Fourth Yangtze River Bridge and Maanshan Yangtze River Bridge, the effects of the first sinking height, sinking feasibility index and excavation method on the sinking of large caissons were investigated. The results show that the first incremental height is constrained by the bearing capacity of the foundation and the gravity stress level of the caisson, and it is conservative to evaluate the deformation during the incremental period according to the results of load-plate experiment; due to the errors of the loading model and parameter selection, the suitability of traditional sinking feasibility index is reduced; the early drainage sinking is the most unfavorable stage, and the flexural rigidity must be considered to select the suitable excavation method during the drainage sinking of the large caissons.

关 键 词：桥梁工程 大型沉井 理论分析 下沉控制 适用性 抗弯刚度 

分 类 号：U443.131[建筑科学—桥梁与隧道工程]