复杂岩层水域大体积现浇异形混凝土承台施工技术研究

武穴长江公路大桥15号墩承台为哑铃形承台,承台尺寸58.8m×28.8m×7m,浇筑方量9 560.2m3,封底混凝土厚5m,承台下设38根直径3m、桩长84m的钻孔灌注桩。选取适宜的混凝土材料参数及配比,采用MIDAS/FEA有限元分析软件辅助开展温控计算,分别对无管冷分块不分层、有管冷分块不分层、无管冷分块分层、有管冷分块分层4种情况开展计算,分析最高温、最大内表温差、温度应力等开裂风险影响参数的变化。同时,介绍了大体积异形承台预留后浇带分层分区浇筑技术、大体积承台后浇带模板整体式支撑技术、大体积承台后浇带温控技术等施工关键技术,为大体积现浇混凝土施工提供整体保障。

Research on Construction Technology of Large Volume Cast-in-place Concrete Pile Caps in Waters with Complex Rock

The 15# pier cap of Wuxue Yangtze River Highway Bridge is a dumbbell-type cap.The size of the cap is 58.8 m×28.8 m×7 m,the concrete at the back cover is 5 m thick,and 38 cast-in-place piles with a diameter of 3 m and a pile length of 84 m are placed under the cap.The casting amount is 9 560.2 m~3.The parameters and proportions of suitable concrete materials were selected,and the temperature control calculation was carried out by MIDAS/FEA finite element analysis software.The nonpipe cold block was not stratified,the pipe cold block was not stratified,and the tubeless cold block was divided.The calculations were carried out in four cases of layer and tube cold block stratification,and the changes of the influence parameters of the highest temperature,maximum internal temperature difference and temperature stress were analyzed.At the same time,it introduces the key technology of construction,such as large-sized special-shaped caps,post-casting zone,layered and zoning,large-scale caps,postcasting formwork,and high-volume caps,post-casting,temperature control technology,etc.The overall protection of cast-in-place concrete work.