浅滩裸岩区锁扣桩围堰施工技术方案研究

Study on Construction Technology Scheme of Locked Pile Cofferdam in Shoal Bare Rock Zone

大冲邕江特大桥9#塔柱为桩承台式基础,河床上覆盖层冲刷严重,承台底标高处均为裸岩。综合考虑该桥塔柱以及主桥梁部的施工特点,讨论单壁、双壁钢围堰和筑岛锁扣桩3种施工方法在该特殊工程环境下的适用性。利用模糊综合评价法,以安全性、施工速度、经济指标和对环境影响大小为基本评定指标,对3种备选方案进行综合量化评估。在此基础上,对选定的施工方法进行了有限元分析。结果表明:筑岛锁扣桩围堰施工方案经济费用较低,施工风险小,工期短,综合效益显著。

Dachongyong river super-large bridge 9#pylon is pile cap foundation,the overlay of river bed is scoured badly,pile cap bottom elevation is the bare rock.Considering the pylon and the main bridge construction characteristics,the applicability of the construction methods such as the single-wall steel cofferdam,double-wall steel cofferdam and building-islands locked pile construction in special engineering environment were discussed in this paper.Based on fuzzy synthetic evaluation,three alternatives were evaluated quantitatively by taking security,construction speed,economic indicators and the environmental impaction as the basic evaluation indicators.The finite element method was used to analysis construction stage of design cofferdam.The results showthat the building-island with locked pile cofferdam construction scheme,its economic cost is lower,construction risk is smaller,construction period is shorter,the comprehensive benefit is remarkable.