摘要
以五峰山长江大桥北锚碇沉井首次下沉为工程背景开展现场载荷板试验,得到沉井荷载作用下土体固结后复合地基极限承载力,计算了沉井首次开挖下沉所需开挖面积,对比分析了锅底开挖下沉、新型十字拉槽以及预留核心土开挖下沉方法。结果表明:由于沉井接高过程中复合地基极限承载力明显提高,须考虑复合地基的固结效应,得到真实的地基极限承载力。采用锅底开挖下沉方法沉井开裂风险大;采用新型十字拉槽以及预留核心土开挖下沉方法,沉井结构安全。与预留核心土和锅底开挖下沉方法相比,十字拉槽法对下沉困难和地基不均匀性有更好的适应性,是一种适用于大型沉井首次下沉的方法。十字拉槽法首次应用于五峰山长江大桥北锚碇特大型沉井施工,保证了沉井顺利安全、快速下沉。
Taking the first sinking of the north anchor caisson of Wufengshan Yangtze River Bridge as the engineering background,the field load plate test was carried out to obtain the ultimate bearing capacity of the composite foundation after soil consolidation under the load of the caisson.The excavation area required for the first excavation and sinking of the caisson was calculated,and the excavation and sinking methods of pot bottom excavation,the new type of cross drawing groove and reserved core soil were compared and analyzed.The results show that because the ultimate bearing capacity of composite foundation increases obviously in the process of caisson connection,the consolidation effect of composite foundation in the process of caisson connection should be considered,and the ultimate bearing capacity of real foundation should be obtained.The caisson has a high risk of cracking by using the excavation and sinking method of large pot bottom.The caisson structure is safe by using the excavation and sinking methods of the new type of cross drawing groove and the reserved core soil.Compared with the excavation and sinking methods of reserving core soil and large pot bottom,the cross drawing groove has better adaptability to the difficulty of sinking and the non-uniformity of foundation.It is a method suitable for the first sinking of large caisson.This method is applied to the construction of the super large caisson of the north anchorage of Wufengshan Yangtze River Bridge for the first time,which ensures the smooth,safe and rapid sinking of the caisson.
作者
潘桂林
李德杰
冯龙健
PAN Guilin;LI Dejie;FENG Longjian(CCCC Second Harbour Engineering Co.Ltd.,Wuhan 430040,China;Geotechnical Research Institute,Hohai University,Nanjing 210098,China)
出处
《铁道建筑》
北大核心
2021年第12期48-51,57,共5页
Railway Engineering
关键词
五峰山长江大桥
锚碇基础
载荷板试验
特大型沉井
开挖下沉
开挖方法
Wufengshan Yangtze River Bridge
anchorage foundation
load plate test
super large caisson
excavation and sinking
excavation method
