文档介绍：
复合地基中褥垫层的极限下限分析
周志军 1,王连坤 1,王敏容 1,楼辉波 2,楼旭伟 2
(1. 五邑大学土木建筑学院,广东江门 529020;2. 奉化市交通投资公司,浙江奉化
315500)
摘
要:作为复合地基的重要组成部分,褥垫层影响着路堤下复合地基的桩、土承载力的发挥,所以有必
要对其承载与变形特性进行研究。根据极限分析下限法,在满足应力边界条件和摩尔-库伦屈服条件下,通
过构建应力场、应力叠加计算等步骤,分别推导出褥垫层在厚度无穷大和厚度较小时的极限承载力下限解,
以及桩土应力比计算公式。通过算例及分析,揭示了褥垫层存在压密和塑性流动两个受力变形阶段;桩土
应力比随着内摩擦角的增大而增大,随着褥垫层厚度的增大而减小等规律;以及桩土应力比试验值与理论
计算值偏差的原因。
关键词:复合地基;褥垫层;极限承载力;极限分析法;桩土应力比
中图分类号:TU472
文献标识码:A
Lower bound limit analysis of cushion posite
foundation
Zhou Zhijun1, Wang Liankun1, Wang Minrong1, Lou Huibo2, Lou Xuwei2
(1. School of Civil Engineering and Architecture, Wuyi University, Jiangmen,Guangdong
529020, China; 2. munications pany, Fenghua, Zhejiang 315500,
China)
Abstract: Cushion, an ponent of posite foundation, exerts influences on the
bearing capacity of the pile and soil posite foundation under embankment, so it is necessary to
make a study on the cushion’s bearing and deformation characteristics. According to the lower bound
limit analysis method, through steps like stress filed construction and stress superposition calculation
while the stress of boundary was accorded with the fact condition and cushion’s yield condition was
met with mohr-coulomb criterion, the lower-bound solutions of the cushion’s ultimate bearing capacity
were derived respectively when the cushion’s thickness was infinite and small, and formulas to
calculate the pile-soil stress ratio could also be deduced. Through examples and analyses, two phases in
the cushion’s deformation are revealed, paction and plastic flow process. Furthermore, it is
also found that the pile-soil stress ratio increases as the internal friction angle increases, but decreases
along with the enlargement of the cushion’s thickness. Besides, reasons for the deviation of the
experimental value from the theoretical value of the pile-soil stress ratio are explored.
Key words: composite foundation; cushion; ultimate bearing capacity; limit analysis method; pile-soil
stress ratio