超长大直径群桩基础室内模型试验的研究.pdf

摘要超长大直径群桩基础室内模型试验研究摘要本课题是国家科技支撑计划项目(2006BAG04800),是《千米级斜拉桥技术标准和关键结构及特性研究》项目下的子项目,本文以室内模型试验为基础,对超大直径单桩、群桩承载性能进行了研究。开展的主要工作如下: 首先,通过调研,总结了关于超大直径桩的工作性能及荷载传递机理,总结了目前一些学者提出的桩侧、桩端荷载传递函数方法以及目前国内外关于超长桩室内模型试验的研究成果; 其次,通过调研和分析,设计并完成了国内最大的超长大直径群桩模型试验,这包括对桩模型的相似比的计算、桩型的选择、数据线的布置、模型的埋置和仪器的选用与架设等等,并通过测试, 获得了可靠的实验数据; 第三,通过超长桩模型试验研究结果分析,研究超长灌注单桩和群桩在竖向荷载作用下的荷载传递机理等问题,得出了一些有实际指导意义的结论; 最后,以试验数据为基础,,验证了课题组关于单桩的荷载传递函数符合双曲线模型的结论;室内模型试验测试Q-s[曲线与按等效墩模型计算的Q-s 曲线进行对比,可以看出两者很接近,验证了按等效墩模型计算本群桩试验模型是适合的。关键词:群桩基础,超大直径,模型试验,荷载传递机理,数值模拟 ABSTRACT Modle TestStudy On Super-long And Big—diameter PileGroup ABSTRACT Being part ofNational Science and Technology Fund projects,thissubject isthesubproject of Technical SmndardS and Key Characteristics ofThousand-meter Scale Cable-stayed indoor model test,thebearing performance ofthelarge diameter piles and thepile groups main work asfollows: Firstofall,through researching thispaperaggregates thelarge-diameter pile on thework performance and load transfermechanism,and sums up thecurrent number ofacademics side ofthepile,pile—load transfer function method and theresults ofthe current domestic and long pile 011theindoor model Secondly,through research andanalysis,the paper designs the nation's largest modle test on super-long and big-diameter includes thecalculation ofsimilarity scale on pile,the selection ofpile model,the layout of dataline,model buried,reasonable choice and erection ofinstruments, ,a reliableexperimental data obtained. Thirdly,through researching on theresult ofthemode teststudy on super-long andbig-diameter pile group,the load-transfermechanism ofthesuper-long bored pile areresearched,some guidance conclusions 羽屯given. Eventually,parison ofthemeasured andcalculated values Oilpileload-settlement curve on apilot basis of testdata,verifies thatthepile of loadtransfer function isin linewith theconclusions of hyperbolic model. By contrasting the9昭curve of