中马友谊大桥主桥深水基础临时结构设计及施工技术  

Design of Temporary Structures in Deepwater Foundation Construction of China-Maldives Friendship Bridge and Construction Techniques

作　　者：李宁[1] 杜松[1] 王振 刘修成 LI Ning;DU Song;WANG Zhen;LIU Xiucheng(CCCC Second Harbor Engineering Co.,Ltd.,Wuhan 430040,China)

机构地区：[1]中交第二航务工程局有限公司,湖北武汉430040

出　　处：《桥梁建设》2023年第4期147-154,共8页Bridge Construction

摘　　要：援马尔代夫中马友谊大桥主桥为(100+2×180+140+100+60)m混合梁V形支腿连续刚构桥,主墩均采用高承台群桩基础。该桥主墩基础施工面临珊瑚礁地层、深海、长周期波涌浪、航空限高及31个月超短工期等不利条件,桩基础采用全栈桥+钻孔平台方案施工,承台采用有底单壁钢吊箱围堰方案施工。在深水基础临时结构设计时,采用高桩大跨栈桥,应用半刚构体系将栈桥跨度提高至46.4 m;通过试桩等效水平推力试验得到钢管桩在波流循环作用下礁灰岩地层承载力设计依据;研发一种带叠合底板的钢吊箱围堰,解决了素封底混凝土开裂失效的问题。施工时,通过钢管桩打入性分析验证了大直径钢管桩在礁灰岩地层中施沉的可行性;研发高精度海浪预报系统,寻找作业窗口,保证栈桥沉桩效率;应用大刚度导向架及高精度调位系统,控制钻孔平台钢护筒基础的施沉精度;采用平台装配式整体吊装工艺,提高了恶劣海况下的施工效率及安全性;采用水封+干封二次封底工艺,保证了钢吊箱的封底质量。主桥深水基础下部结构在14个月时间完成,达到施工安全和主体结构质量控制目标。The China-Maldives Friendship Bridge is a hybrid girder,continuous rigid-frame bridge that consists of two main spans of 180 m,a longer side span of 140 m,two symmetrical side spans of 100 m and a short side span of 60 m.The bridge features the V-shaped main piers that are mounted on high-rise pile caps supported by bored piles.To address the adverse factors in pile foundation construction,including coral reef formation,deep sea,long-period waves,aeronautical clearance and 31-month construction schedule,the combined utilization of full trestle and boring platform was selected.A bottomed single-wall steel box cofferdam was employed in the construction of the pile cap.A high-pile-supported long-span trestle was designed,owing to the utilization of a semi-rigid system,the span length of the trestle could be increased to 46.4 m.Equivalent horizontal thrust test was carried out on trial piles to investigate the load bearing capacity of the steel pipe piles in reef limestones under the action of waves and currents.To address the cracking issue of conventional plane concrete sealing of cofferdam,a type of steel box cofferdam with composite bottom was prepared.The feasibility of applying large-diameter steel pipe piles in reef limestones had been verified by analyzing the drivability of the steel pipe piles.A high-precision wave forecasting system was developed to capture the window time to ensure the pile sinking efficiency.High-rigid frames and high-precision positioning system were applied to control the sinking accuracy of the steel casings in the boring platform.To improve the construction efficiency and safety of the boring platform,an integral hoisting technique was applied.The bottom of the cofferdam underwent two stages of sealing,namely the water sealing and dry sealing,to guarantee the sealing quality.The construction of the deep-water substructure of the main bridge was completed in 14 months,achieving the expected safety and quality control targets.

关 键 词：刚构桥 高桩承台 栈桥 钻孔平台 大直径钢管桩 钢吊箱围堰 临时结构设计 施工技术 

分 类 号：U448.23[建筑科学—桥梁与隧道工程] U445.4[交通运输工程—道路与铁道工程]