摘要
南京长江四桥北锚碇沉井是目前世界上最大的矩形沉井,长69m,宽58m,高52.8m,其首次降排水下沉需要处理下沉精度、结构安全和附近长江大堤沉降等问题。通过现场开挖控制、应力监控和大堤沉降观测表明,在不同下沉阶段采用不同的开挖策略是能够保证沉井下沉精度的;在沉井下沉前期,开挖方案对结构安全起控制性作用,后期则由于土体对沉井侧壁约束作用的加强,下沉深度越大结构越安全;长江大堤的沉降主要由承压含水层的压缩引起,并且产生的沉降量较小,没有出现安全问题;南京长江四桥北锚碇的首次降排水下沉是非常成功的。
The Fourth Nanjing Yangtze River Bridge's north anchorage caisson,which is the largest caisson in the world,has a length of 69 m,width of 58 m and height of 52.8 m.During the dewater sinking,the position precision,the structure safety and the settlement of dike nearby are need to be considered.Through excavation plan control,stress monitoring and settlement measuring,it reveals that the precision of sinking can be controlled by selecting proper excavation plans at different stages.For the structure safety,it is affected mostly by excavation plan at early sinking stage;As the sinking depth increases,the earth pressure and skin friction on caisson wall can reduce the tensile stress;The deeper the caisson goes,the more safe the structure.Settlement of dike is caused mainly by compression of confined water aquifer,and it's very small.No safely problem appeared.
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2010年第S2期537-540,共4页
Chinese Journal of Geotechnical Engineering
关键词
沉井
下沉
降水
开挖方案
结构安全
沉降
caisson
sinking
dewater
excavation plan
structure safety
settlement
