摘要
为了进一步明确筒桩桩承式加筋路堤的工作机制,在广州绕城高速公路九江—小塘段进行现场试验。试验结果证明,筒桩单桩竖向承载力大,均以刺入方式破坏,并且筒桩单桩复合地基承载力大,沉降小。筒桩桩承式加筋路堤荷载传递机制主要受"土拱效应"和"拉膜效应"控制,桩土应力比随路堤荷载以及桩顶与桩间土之间沉降差的变化而变化。路堤荷载下筒桩复合地基,总沉降小,桩帽上和桩间土上的土体存在沉降差,沉降差的发展可以反映土拱效应的发挥程度。另外,路堤荷载在地基土中产生的超孔隙水压力很小,且随深度迅速减小,地下6.0m处超孔压已接近0。路堤侧向变形小且随深度迅速减小,最大侧向变形发生在地下3.0～4.5m处。
To validate the working mechanism of reinforced embankment supported by cast-in-situ thin-wall tubular piles,field test has been performed in a highway section from Jiujiang to Xiaotang around Guangzhou City.Test results show that tubular pile has a large vertical bearing capacity,and punching failure happens to most piles in static tests.Moreover,the bearing capacity of single tubular pile composite foundation is also large with small settlements.Tests still suggest that soil arching effect and tension membrane effect are the two key factors influencing the load transfer mechanism.The pile-soil stress ratio varies with the embankment loads and differential settlements between piles and soil.The total settlement of tubular pile composite foundation under embankment load is small.Differential settlements are found between soil above pile cap and soil among piles,respectively,and increase of this difference can reflect the degree of soil arching effect.In addition,excess pore water pressure,which is induced by embankment loads,turns up slightly and decreases rapidly along depth.It is nearly zero at the depth of 6.0m.The lateral deformation of embankment is small,and decreases rapidly along depth;and it reaches its peak value at the depths of 3.0 to 4.5m.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2010年第9期1929-1936,共8页
Chinese Journal of Rock Mechanics and Engineering
关键词
桩基工程
筒桩
桩承式加筋路堤
现场试验
pile foundations
cast-in-situ thin-wall tubular pile
pile-support reinforced embankment
field test
