郑西客运专线桥梁桩基摩阻力试验研究  

Experimental Study on Frictional Resistance of Bridge Pile Foundation of Zhengzhou-Xi'an Passenger Dedicated Line

作　　者：陈子文[1] 

机构地区：[1]中铁二院工程集团有限责任公司,成都610031

出　　处：《高速铁路技术》2016年第3期42-48,共7页High Speed Railway Technology

摘　　要：根据郑西客运专线的地质条件,三门峡至灵宝段桥梁全部采用钻孔灌注桩基础,桩数多且桩较长,桩基穿过砂质黄土、黏质黄土、粉细砂层、圆砾土等,为合理确定桩侧摩阻力、桩基承载力等,很有必要进行桩基摩阻力试验研究。试桩采用慢速维持荷载法,实测得到各试桩的Q^s曲线,进而导出桩身轴力、桩周摩阻力、端阻力变化以及在极限承载力下各土层对桩的摩阻力和端阻力等。实验结果表明,各桩桩身轴力均随桩的深度的增加而递减,反映出摩擦桩的特征;摩阻力沿桩身的分布呈"单峰状";在极限荷载下,试桩端承力仅占桩顶荷载的2.1%~8.1%。通过该实验,不仅优化了郑西客运专线桥梁基础设计,取得了可观的经济效益,也为类似场地中的桩基设计提供了参考。According to the geological conditions of Zhengzhou-Xi＇an Passenger Dedicated Line,cast-in-situ bored pile foundation is adopted on all the bridges built on Sanmenxia-Lingbao section. Due to the fact that there are a large number of relatively long piles,and the foundation of piles are constructed in sandy loess,loess,clayey silty sand layer,round gravel soil,etc.,frictional resistance experimental study is necessary to decide the pile lateral friction and the bearing capacity of pile foundation. Low speed load-keeping method is adopted in this thesis to measure the Q ~ s curve of the test pile,and thus get the axial force of pile shaft,resistance around the pile,pile end resistance change,and the friction resistance and end resistance of the pile in different soil under ultimate bearing capacity,etc. The experimental results show that the axial stress of the pile would decrease with the increase of the depth of the pile,which reflects the characteristics of the friction pile; The distribution of friction resistance along the pile shaft is unimodal; Under ultimate load,the end-bearing capacity of the test pile only accounts for 2. 1% ~ 8. 1% of the pile top load. The experiment has not only optimized the bridge foundation design of Zhengzhou-Xi＇an Passenger Dedicated Line, but also created considerable economic benefits,and provided a reference for the pile foundation design of similar sites.

关 键 词：桥梁桩基 摩阻力 试验研究 极限承载力 湿陷性黄土 

分 类 号：U443.15[建筑科学—桥梁与隧道工程]