附加应力法计算刚性桩复合地基路基沉降  

Superimposed stress method to calculate settlement of embankment with rigid-pile composite foundation

作　　者：刘吉福 郑刚[2] 龚晓南[3] LIU Ji-fu;ZHENG Gang;GONG Xiao-nan(CRCC Harbour ＆ Channel Engineering Group Co.,Ltd.,Zhuhai 519000,China;School of Civil Engineering,Tianjin University,Tianjin 300072,China;Research Center of Coastal and Urban Geotechnical Engineering,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]中国铁建港航局集团有限公司,广东珠海519000 [2]天津大学建筑工程学院,天津300072 [3]浙江大学滨海与城市岩土工程研究中心,浙江杭州310058

出　　处：《岩土工程学报》2018年第11期1995-2002,共8页Chinese Journal of Geotechnical Engineering

摘　　要：部分刚性桩复合地基路基实际沉降超过计算沉降的重要原因之一是现有沉降计算方法存在严重缺陷。在分析桩土沉降关系和桩土作用的基础上,提出了路堤下刚性桩复合地基沉降计算新方法——附加应力法。首先根据桩土作用计算桩土附加应力,然后采用分层总和法计算复合地基沉降。经工程实例验证后,利用附加应力法研究了桩长、桩间距、扩底、桩帽等因素对路基沉降的影响,并与现行方法计算的沉降进行对比。分析表明：附加应力法可以考虑单桩竖向承载力、桩帽转移荷载能力、桩土相互作用等因素的影响,计算沉降与实测沉降接近;利用桩帽将路堤大部分荷载转移到桩顶可以有效减小路基沉降;扩底比桩长加大更经济合理;按＂强桩、大间距、大桩帽＂原则设计的复合地基比密桩复合地基更经济合理。An important cause for the practical settlement of some embankments with rigid-pile composite foundation larger than calculated settlement is the severe serious defects of the existing methods for settlement calculation. The superimposed stress method is proposed for calculating the settlement of a rigid-pile composite foundation under embankment by analyzing the differential settlements and interactions between piles and soils. The settlement of the composite foundation is gotten by the layer-wise summation method after the superimposed stresses of piles and soils among piles are calculated based on the analysis of interactions between piles and soils. The proposed method validated by a practical project is applied to investigate the influences of length, distance, enlarged base and cap of rigid piles on the settlements of composite foundation of embankment. The settlements calculated by the proposed method and the existing methods are compared. It is proven that the bearing capacity of piles, load transferred to piles by pile cap, interaction between piles and soils can be taken into account by the proposed method, and the calculated settlement is close to the practical settlement. The pile cap which transfers most embankment load to the piles can decrease settlement prominently. The under-reamed pile is more economical and reasonable than the length-increasing pile. The composite foundation consisting of sparse strong piles with large caps is more economical and reasonable than the composite foundation consisting of dense piles.

关 键 词：刚性桩 路基 沉降 附加应力法 扩底桩 桩帽 等沉面法 等沉区法 

分 类 号：TU470[建筑科学—结构工程]