椒江二桥索塔大直径超长嵌岩桩基础设计探讨

Design research on large diameter ultra-long rock socketed pile foundation of No.2 Jiaojiang Bridge

椒江二桥索塔基础采用大直径超长钻孔灌注桩基础,按嵌岩桩设计,最长桩长达到139 m,为国内桥梁工程中之最,目前试桩工程已经取得成功。现以南索塔基础为例,通过对其基础形式的比选,详细分析桩基础与沉井基础对于此工程的适宜性,并通过结合现行规范计算及桩土岩共同作用机理分析,探讨当前桥梁设计中钻孔灌注嵌岩桩基础设计应注意的几个问题,并提出本工程基础在承载力方面的特性。

The tower foundation of No.2 Jiaojiang Bridge is design as large diameter ultra-long cast-in-place bored pile with rock-socketed piles,with 139m in maximum length,which is the longest in domestic bridges,and pile test is successful.Taking the southern tower foundation as an example,pile foundation and caisson foundation forms with their suitability for this project have been compared. The paper discussed some key problems about cast-in-place rock-socketed pile in current bridge design,combined with calculation based on current specifications and analysis of mechanism of interaction of pile,soil and rock,and it also figures out the bearing capacity characteristic of this project.