大型桥梁圆形沉井锚碇下沉过程中力学特性监测分析  

Monitoring analysis of mechanical characteristics for sinking of super-large bridge circular caisson anchorage

作　　者：邓友生[1,2] 黄恒恒[1] 杨敏[2] 万昌中[1] 时一波[3] 黄峰[3] 

机构地区：[1]湖北工业大学土木工程与建筑学院,湖北武汉430068 [2]同济大学岩土及地下工程教育部重点实验室,上海200092 [3]中铁大桥局集团第六工程有限公司,湖北武汉430100

出　　处：《建筑结构学报》2015年第10期153-157,共5页Journal of Building Structures

基　　金：国家自然科学基金项目(40972179)

摘　　要：武汉鹦鹉洲长江大桥北锚碇采用特大圆形沉井,沉井立面尺寸为66 m×43 m,沉井的下沉控制和结构应力的监测是施工过程中的难点。在沉井施工过程中,在沉井侧壁的不同高度和第2节沉井底部分别安装了大量的侧壁土压力计和钢筋计,用于监测沉井下沉过程中侧壁土压力和沉井底部应力的变化;同时还使用空气幕助沉系统来克服沉井后期下沉的阻力。监测结果表明:沉井侧壁土压力随沉井的下沉逐渐增大,同时沉井的下沉速度降低,其底部结构的应力减小;沉井的最大拉应力与最大压应力均出现在其初次下沉过程中,在随后的两次下沉过程中沉井结构的应力分布较为均衡。由此可见,对沉井的第1次下沉进行结构应力监测和控制非常关键。The north anchorage of Wuhan Parrot Cay Yangtze River Bridge is a super-large circular caisson whose size is up to 66 m × 43 m,thus it is difficult in process of construction to control caisson sinking and its structure stresses.The soil pressure cells and steel bar gauges were installed in the different high caisson walls and the bottom of the second-quarter caisson during the process of construction,to monitor changes of soil pressure of caisson wall and the bottom stresses. And it can remove sinking difficultly in the later caisson sinking process for using the air curtain settling system as well. The results show that the caisson wall soil pressure increase gradually with the caisson sinking,which will not only reduce the speed of caisson sinking,but also reduce the structure stress at the bottom of the caisson. Both the maximum tensile stress and compressive stress occur in the first sinking process. The distribution of stresses in caisson is more balanced during the last two times sinking. Therefore,the first sinking process is the key to the structure monitoring.

关 键 词：大跨度桥梁 圆形沉井锚碇 结构监测 侧壁土压力 结构应力 

分 类 号：TU473.2[建筑科学—结构工程]