援马尔代夫中马友谊大桥深水基础设计  

Design of Deepwater Foundations of China-Maldives Friendship Bridge

作　　者：邱远喜 肖海珠[1] 李华云[1] 谭国宏[1] QIU Yuan-xi;XIAO Hai-zhu;LI Hua-yun;TAN Guo-hong(China Railway Major Bridge Reconnaissance&Design Institute Co.,Ltd.,Wuhan 430056,China)

机构地区：[1]中铁大桥勘测设计院集团有限公司,湖北武汉430056

出　　处：《桥梁建设》2018年第6期93-98,共6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。为适应桥址处特殊的珊瑚礁地质条件和恶劣的强涌浪深水海洋环境,主桥基础均采用高承台群桩基础。19号、23号主墩采用7根直径3.2～2.8m的变截面钻孔灌注桩,20～22号主墩采用7根直径3.6～3.2m的变截面钻孔灌注桩,桩基均按梅花形布置。19号主墩桩位处海床坡度较陡,选用高低桩方案,桩长98m和108m。23号主墩墩位地层中存在大型空洞,故该墩桩基穿过空洞区进入其下方稳定地层2倍桩径左右,桩长均为75m。20～22号主墩桩长分别为110,106,88m。各墩均设置六边形承台,承台厚度均为4.0m,承台顶面以上设置基座与V形支腿或主梁0号块相连。为提高单桩水平承载力,将钢护筒设计为永久结构,共同抵抗桩身弯矩。利用桩底后压浆处理提高桩基竖向承载力。The main bridge of China-Maldives Friendship Bridge is a V-type outriggers composite girder continuous rigid frame bridge with span arrangement(100+2×180+140+100+60)m.To accommodate the special coral reef geology and atrocious surge deepwater environment,the foundations of the main bridge are designed as high capped pile group foundation.The foundation of No.19 and No.23 main piers are composed of 7 variable cross section bored piles with diameter of 3.2-2.8 m,and the foundations of No.20 to No.22 main pier are composed of 7 variable cross section bored piles with diameter of 3.6-3.2 m,all piles are arranged in quincunx.Because of the steepy slope of seabed at the position of main pier No.19,its foundation is designed as high and low composite piles with pile length 98 m and 108 m.There is a large cavity in the stratum of No.23 main pier,so its pile foundation should pass through the cavity area and enters the stability stratum about 2 times pile diameter depth.Its pile length is 75 m.While the pile length of No.20 to No.22 main piers are respectively 110 m,106 m,and 88 m.Each pier is set a hexagonal pile cap with a thickness of 4 m.On the top of the pile cap,there is a pedestal being set to connect with the V support leg or the main girder block 0.To improve the horizontal bearing capacity of single pile,the steel casings are designed as a permanent structure to help the plies to resist bending moment.Meanwhile,pile-bottom post-grouting technology is employed to improve the vertical bearing capacity of pile foundation.

关 键 词：跨海大桥 刚构桥 珊瑚礁地质 深水基础 变截面钻孔灌注桩 群桩基础 钢护筒 

分 类 号：U448.23[建筑科学—桥梁与隧道工程] U443.154[交通运输工程—道路与铁道工程]