按桩顶沉降控制的嵌岩桩嵌岩深度计算方法  

Calculation Method of Socketed Length of Rock Socketed Pile Based on Requirement of Pile Top Settlement

作　　者：雷勇[1] 赵明华[1] 马缤辉[1] 

机构地区：[1]湖南大学岩土工程研究所,湖南长沙410082

出　　处：《公路交通科技》2011年第5期86-91,共6页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金项目(50378036)

摘　　要：深入探讨了嵌岩桩的荷载传递机理,针对目前规范采用的嵌岩桩嵌岩深度计算方法的不足,根据嵌岩桩承载机理建立荷载传递方程,提出按基桩竖向荷载传递特性确定嵌岩桩嵌岩深度的计算方法,并得到桩端荷载分担比与嵌岩深度的表达式。通过算例深入研究了嵌岩深度及桩端荷载分担比随桩顶沉降变化规律。结果表明,同等条件下桩顶沉降要求越小,所需嵌岩深度越大;沉降越大,桩端所承受荷载比例越大;桩端荷载分担比随嵌岩比的增加而减小。该方法可同时考虑上部结构对沉降的要求与桩端荷载分担的比率,从安全和经济角度综合确定嵌岩桩的嵌岩深度。Loading transfer mechanism of rock-socketed pile was deeply discussed.In view of the existing deficiency of the calculation method used in current standard for socketed length of rock-socketed pile,the load transfer equation was established according to the bearing mechanism of rock-socketed pile,the calculation method of the socketed length of rock-socketed pile was obtained based on the vertical load transfer characteristics of pile,and the expressions of pile tip load-sharing ratio and rock-socketed length were obtained.Finally,the variational behaviors of rock-socketed length and pile tip load-sharing ratio with pile top settlement were studied based on an engineering example.The results indicate that under the same conditions,（1） the smaller the requirement of pile top settlement is,the greater the required rock-socketed length is;（2） the greater the settlement is,the greater the bearing contribution of pile tip is;（3） the pile tip load-sharing ratio decreases with the increase of rock-socketed proportion.This method takes into account the settlement requirements of upper structure as well as the load-sharing ratio of pile tip,so the rock-socket length can be determined comprehensively from safety and economic aspects.

关 键 词：桥梁工程 嵌岩桩 荷载传递机理 桩端荷载分担比 嵌岩深度 

分 类 号：U443.15[建筑科学—桥梁与隧道工程] TU473[交通运输工程—道路与铁道工程]