基于离心模型试验的高强度桩复合地基桩帽效应分析  

Analysis on pile cap effect in composite foundation with high strength pile by centrifugal model tests

作　　者：BUI Phu Doanh 罗强[1] 张良[1] 

机构地区：[1]西南交通大学土木工程学院,四川成都610031

出　　处：《岩土工程学报》2008年第8期1158-1164,共7页Chinese Journal of Geotechnical Engineering

基　　金：铁道部科技研究开发计划项目(2007G012)

摘　　要：桩帽的设置及其覆盖率的变化对高强度桩复合地基的工程特性影响巨大,对桩帽尺寸的合理设计是实现高强度桩–桩间土–加筋垫层协调承载和变形控制的技术关键。结合某铁路新建双线段(v≥200 km/h)现场软基处理工点的具体情况,进行了4组设置桩帽的高强度桩复合地基离心模型试验,测试了地基变形、桩身应变、桩帽顶面及桩间土压力、垫层拉筋受力等数据。试验数据表明:①在桩顶设置桩帽能有效发挥高强度桩的承载能力,调整桩和桩间土的荷载分配,提高地基的稳定性;②在桩间距不变的条件下,地基变形、垫层拉筋受力、桩帽顶面及桩间土压力等随桩帽覆盖率的提高而减小,桩土应力比则增加;③垫层拉筋受力沿路基横截面基本呈M型对称分布,峰值出现在左右路肩附近位置,与地基的剪切破坏位置有较好的一致性。The effect of pile caps with various sizes on engineering properties of composite foundation with high strength pile was great. Specific data were collected from the settlement of a soft clay foundation in new double-line railway （v〉200 km/h） project. 4 sets of centrifugal model tests were conducted using CFG pile with different sizes of pile cap for soft clay foundation. The pile strain, distribution of pressure on pile caps and on earth, and stress of reinforcement were measured. It was shown that： （1）The stability of embankments was raised by CFG piles with caps. （2）The larger the size of pile cap, the greater the variation of embankment and decrease of strain of reinforcement with increase of pile strain. （3）The reinforcement was distributed in a shape of M along the transverse section. The peak values occurred at the road abutment, indicating good agreement with the failure position of embankmats.

关 键 词：离心模型试验 软土地基路堤 高强度桩复合地基 桩帽效应 

分 类 号：TU41[建筑科学—岩土工程]