摘 要：
桩数沉降关系是按变形控制设计桩基础（减少沉降桩基础设计）的重要依据，受荷载大小、桩位布置和场地类别等多个因素共同影响。结合某工程现场实测数据，运用近似数值方法和平面应变有限元方法对2幢采用不同桩数的多层住宅桩筏基础进行计算分析，研究不同桩间距对地基压缩变形、基础内力和土体应力应变分布的影響，对桩数减少一半时基础沉降几乎没有变化这一问题给出合理解释。结果表明，作用于基础顶面的荷载水平越低，桩侧与桩端土层可压缩性差异越小，基础沉降量对桩数变化越不敏感。对于深厚软土地基中的低承台群桩基础，按变形控制进行桩基设计，能最大程度地节约基础用桩量，可获得十分显著的经济效益。
关键词：
减沉桩；沉降；桩数；近似数值解法；有限元法
中图分类号：TU473.1
文献标志码：A 文章编号：16744764（2018）05003410
收稿日期：20170921
基金项目：
国家自然科学基金（41372274）
作者简介：
杨军（1985），男，博士，主要从事地基基础检测研究，Email：yangjun851113@163.com。
杨敏（通信作者），男，教授，博士生导师，Email：yangmin@tongji.edu.cn。
Received：20170921
Foundation item：
National Natural Science Foundation of China （No. 41372274）
Author brief：
Yang Jun（1985）， PhD，main research interest： foundation testing， Email：yangjun851113@163.com.
Yang Min（corresponding author）， professor， doctoral supervisor， Email：yangmin@tongji.edu.cn.
Case analysis of settlement control mechanism for
settlement reducing pile
Yang Jun1，Yang Min2，Luo Ruping2
（1.Guangdong Hualu Transport Technology Co.， Ltd， Guangzhou 510420， P. R. China；
2.School of Civil Engineering， Tongji University， Shanghai 200092， P. R. China）
Abstract：
The relationship between pile numbers and settlement is the most important reference for pile foundation design， based on the deformation control （or design of reducing settlement pile foundation）， which is affected by several factors， such as the loading magnitude，the pile arrangement and the soil type. Combined with the measured data from case history， the approximate numerical method and plane strain finite element method are put forward to analyze two piled raft foundations with different pile numbers for multistorey residential buildings. The effects of different pile spacings on compressive deformation， internal force of foundation and stressstrain distribution of soils are studied， and a reasonable explanation is given for the problem that foundation settlement is almost unchanged after the pile number is reduced by half. The results show that， the lower the loading magnitude or the smaller the compressibility difference between pile side and pile tip soil layer， the foundation settlement is less sensitive to the change of pile numbers. For lowcap pile group foundation in deep soft soil， pile foundation design based on deformation control can reduce pile numbers considerably， with significant economic benefits.
