摘要
虎跳峡金沙江大桥原设计隧道锚右洞散索鞍支墩基础为扩大基础。由于施工隧道锚的需要,隧道锚复合索鞍支墩下方开挖有一条施工便道,施工便道上边坡顶距原设计复合索鞍支墩基础距离3.5m,边坡高度约10m,从隧道锚下方施工便道上边坡开挖揭示的地质情况可以看出,隧道锚右洞复合索鞍支墩基础前缘均为碎、块石堆积体。隧道锚复合索鞍支墩基础原位荷载试验单位提供的国家高速公路网G0613云南省香格里拉至丽江高速公路虎跳峡金沙江大桥《隧道锚岩石力学实验报告》(长江水利委员会长江科学院,院编号:Ⅱ201808LYT)中关于隧道锚右洞复合索鞍支墩基础基底承载力容许值为530kPa,远低于设计要求的750kPa。因为上述原因,且为确保桥梁施工和后期运营安全,将隧道锚复合索鞍支墩基础变更为桩基础,共计8根桩基。桩基长度分别为12,15,20,25m,桩基直径2m,桩基混凝土强度等级C30。
The original design of the Jinsha River Bridge in Tiger Leaping Gorge is that the foundation of the saddle piers with scattered cables in the right hole of the tunnel is an expanded foundation.Because of the need of tunnel anchor construction,there is a construction convenient road under the tunnel anchor composite cable saddle pier.The distance from the top of the slope to the original designed composite cable saddle pier foundation is 3.5 m,and the height of the slope is about10 m.It can be seen from the geological conditions revealed by the excavation of the upper slope of the construction convenient road under the tunnel anchor that the front edge of the composite cable saddle pier foundation in the right tunnel anchor hole is all broken and rock accumulation.National highway network G0613 National highway network G06 Committee of the Yangtze Academy of Sciences,The allowable value of bearing capacity of composite cable-saddle pier foundation is 530 kPa inⅡ201808 LYT),which is far lower than the 750 kPa required by the design.Because of the above reasons,and in order to ensure the safety of bridge construction and later operation,the tunnel anchor composite cable saddle pier foundation was changed into a pile foundation,with a total of 8 piles.The length of pile foundation is 12,15,20,25 m respectively,the diameter of pile foundation is 2 m,and the concrete grade of pile foundation is C30.
作者
李同贵
LI Tonggui(Kunming International Airport Construction Command,Kunming,Yunnan 650211,China)
出处
《施工技术》
CAS
2019年第S01期1178-1183,共6页
Construction Technology
关键词
桥梁工程
桩
基础
隧道
锚
施工技术
bridges
piles
foundation
tunnels
anchor
construction
