波浪荷载作用下跨海桥梁群桩基础方案研究
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摘要
针对波浪荷载作用下跨海桥梁群桩基础的设计问题,以平潭海峡公铁两用跨海大桥主桥为工程背景进行了群桩基础方案的数值模拟分析。首先,建立全桥有限元模型计算上部结构对基础的作用力;其次,建立了4种不同群桩基础方案的有限元模型,分别采用Morison方程和绕射理论计算桩基、承台和围堰受到的波浪荷载,并分析了各群桩基础方案在波浪荷载作用下的受力性能;最后,通过比较不同设计方案的工程量及施工可行性,给出了较优的设计方案。研究结果表明:波浪荷载对跨海桥梁围堰设计及施工的影响尤为显著;承台高程提高后可以有效减小围堰承受的波浪荷载,降低施工难度与风险;承台高程提高后采用增大桩径的方法,可以有效改善基础受力性能,减少工程量,控制工程投资。
Aiming at the design problem of group pile foundation of sea-crossing bridge under wave loading,the numerical simulation analysis of group pile foundation scheme of the main bridge of Pingtan strait rail-cum-road seacrossing bridge was carried out under the engineering background. Firstly,the finite element model of the whole bridge was established to calculate the action of the superstructure on the foundation. Secondly,the finite element models of four different group pile foundation schemes were established.The wave loads on pile foundation,cap and cofferdam were calculated by Morison equation and diffraction theory respectively. The mechanical properties of group pile foundation schemes under wave loading were analyzed.Finally,an optimal scheme was given according to the comparsion on the the engineering quantity and construction feasibility of different design schemes of the group pile foundation.The results showthat the influence of wave loads on the design and construction of cofferdam for sea-crossing bridges is particularly significant. The wave loads on cofferdam can be effectively reduced and the construction difficulty and risk can be reduced with the increase of the elevation of cap.On the basis ofincreasing the elevation of cap,the method ofincreasing the diameter of the pile can effectively improve the mechanical properties of the foundation,reduce the amount of work and control the investment of the project.
Aiming at the design problem of group pile foundation of sea-crossing bridge under wave loading,the numerical simulation analysis of group pile foundation scheme of the main bridge of Pingtan strait rail-cum-road seacrossing bridge was carried out under the engineering background. Firstly,the finite element model of the whole bridge was established to calculate the action of the superstructure on the foundation. Secondly,the finite element models of four different group pile foundation schemes were established.The wave loads on pile foundation,cap and cofferdam were calculated by Morison equation and diffraction theory respectively. The mechanical properties of group pile foundation schemes under wave loading were analyzed.Finally,an optimal scheme was given according to the comparsion on the the engineering quantity and construction feasibility of different design schemes of the group pile foundation.The results showthat the influence of wave loads on the design and construction of cofferdam for sea-crossing bridges is particularly significant. The wave loads on cofferdam can be effectively reduced and the construction difficulty and risk can be reduced with the increase of the elevation of cap.On the basis ofincreasing the elevation of cap,the method ofincreasing the diameter of the pile can effectively improve the mechanical properties of the foundation,reduce the amount of work and control the investment of the project.
引文
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[2]孙英杰,梅新咏.平潭海峡公铁两用大桥鼓屿门航道桥主墩基础设计[J].世界桥梁,2016(1):15-19.
[3]谢华灿,郭辉.承台高程提高对大跨度公铁两用斜拉桥的影响分析[J].铁道建筑,2015,55(5):5-8.
[4]郭征红,徐伟.深水群桩基础的关键施工技术研究[J].结构工程师,2007(6):70-73.
[5]遆子龙,李永乐,秦顺全,等.海洋桥梁施工围揠的波浪压力实测与数值模拟[J].西南交通大学学报,2017,52(3):466-473.
[6]陈翔,梅新咏.平潭海峡公铁两用大桥主航道斜拉桥深水基础设计[J].桥梁建设,2016,46(3):86-91.
[7]MORISON J R,O'BRIEN M P,JOHNSON J W,et al. The Force Exerted by Surface Waves on Piles[J].Journal of Petroleum Technology,1950,2(5):149-154.
[8]MACCAMY R C,FUCHS R A. Wave Forces on Piles:A Diffraction Theory[J]. US Army Corps of Engineering,Beach Erosion Board,1954,69:75-86.
[9]竺艳蓉.海洋工程波浪力学[M].天津:天津大学出版社,1991.
[10]WEI K,ARWADE S R,MYERS A T.Incremental Wind-wave Analysis of the Structural Capacity of Offshore Wind Turbine Support Structures Under Extreme Loading[J]. Engineering Structures,2014,79:58-69.
[11]中华人民共和国交通运输部.港口与航道水文规范:JTS145—2015[S].北京:人民交通出版社,2016.
[12]陈伯兴,李继刚,陈亮,等.桥梁基础工程[M].北京:中国建筑工业出版社,2012.