承台钻孔桩基础用叠加法的实用计算  

Practical Calculation with Superposition Method for Drilled Pile Foundation

作　　者：沈中治[1] 王腾[1] 

机构地区：[1]北京市市政工程设计研究总院有限公司,100082

出　　处：《特种结构》2016年第4期90-99,共10页Special Structures

摘　　要：本文介绍桥梁承台钻孔桩基础的一种实用计算方法,其要点是:将地面以上外露的桩群、承台设定为竖向整体悬臂梁,地面以下为弹性基础,外荷载作用在承台底面。整个计算过程是将三种外荷载:水平力、弯矩、竖向力按单项分别作用下计算出桩基的受力效应,最后将各单项结果进行总体叠加,得到上述桩基础的内力、变形的统一计算公式。桩的弹性基础采用m法,计算中取用弹性桩,桩的变形系数αh≥2.5,针对工程中常能满足的出≥4.0的条件,将求内力、变形公式中的系数按αh≥4.0制成图表供以查用,节省了计算工作量。本方法概念明确、表达简单、使用方便,适合初步设计、施工图设计审查时使用。An application of superposition method in drilled pile foundation calculation in bridge design was introduced in this paper. The key point is that it assumes the piles and caps working as a cantilever beam bridge above ground, and as an elastic foundation underground, and external forces work on the bottom of the caps. Pile stress was calculated with such an assumption that three types of external forces-horizontal force, vertical force and bending force work individually, then the formulas of force and transformation were deduced after adding the calculation results together. Method m was used when pile was in elastic state. And its reformation coefficient is αh≥2. 5. TO save time, coefficients in the formulas were calculated and tabulated when αh≥4. 0 which can usually be satisfied in common engineering. With clear concept, simple expression and easy way to use, this method is appropriate in the supervision process of preliminary design and construction design.

关 键 词：钻孔桩 叠加法 变形系数 柔度系数 承台桩基础 

分 类 号：U443.15[建筑科学—桥梁与隧道工程]