珊瑚礁地层大直径桥梁桩基侧摩阻力研究  

Side Frictions of the Large Diameter Piles in the Coral Reef Strata

作　　者：张荣[1] 余颂[1] 张国超[1] 刘建平[1] ZHANG Rong;YU Song;ZHANG Guochao;LIU Jianping(China Railway Major Bridge Reconnaissance&Design Institute Co.Ltd.,Wuhan 430050)

机构地区：[1]中铁大桥勘测设计院集团有限公司,武汉430050

出　　处：《土工基础》2023年第2期188-192,共5页Soil Engineering and Foundation

摘　　要：大直径桩基具有低沉降和高承载力的优点,目前在大型跨江、跨海桥梁工程中使用日趋增多。生物沉积形成的珊瑚礁灰岩,具有弱胶结、结构疏松,高孔隙率等特性,当桥梁桩基置于该地层中,桩侧摩阻力有其独特的规律,传统的桩基侧摩阻力和承载力取值方法并不适用。结合马尔代夫某桥梁工程实例,综合室内模型桩试验、现场自平衡荷载试验等方法,对珊瑚礁地层中的大直径桥梁桩基侧摩阻力和承载力特性进行研究,并将测试结果与规范取值进行对比。结果表明,珊瑚礁地层具有较大的侧摩阻力和承载力,大直径桩基可作为一种常用的基础形式。礁灰岩桩侧摩阻力的发挥经历了接触压密、弹性剪切、剪切破坏和摩擦剪切四个阶段。珊瑚礁地层结构性强,钻探过程易受到扰动,严重降低其力学特性。Large diameter piles have the advantages of high axial capacity and small settlement and are increasingly used in large bridge projects across the river and sea.The coral reef limestone formed by bio-deposition has weak cementation and high porosity characteristics,when the pile foundation of the bridge rock-socketed in this stratum,the side friction has its own characteristics and the traditional method of estimating the pile side friction resistance and axial capacity is not applicable.Combined with a bridge project in Maldives,the characteristics of the side friction resistance and axial capacity of the large diameter bridge pile foundation in the coral reef strata are studied by means of laboratory model test and field self-balancing load test.The test results are compared with the code suggested values.The results show that the coral reef stratum has large side friction resistance and axial capacity,and the large diameter pile foundation can be used as a common foundation form.The side friction of the reef limestone piles has experienced four stages:contact compaction,elastic shear,shear failure and friction shear.The strength of the reef limestone has a large structure,and the drilling process has a great disturbance to the reef limestone stratum,which makes the mechanical properties of the reef limestone significantly reduced.

关 键 词：珊瑚礁灰岩 大直径桩基础 侧摩阻力 承载力特性 

分 类 号：TU473[建筑科学—结构工程]