未打穿砂井复合地基承载机理模型试验研究  

Bearing behavior of ground with partially penetrated sand wells by model testing

作　　者：邹新军[1] 杨眉[1] 赵明华[1] 

机构地区：[1]湖南大学土木工程学院,湖南长沙410082

出　　处：《岩土工程学报》2010年第S2期1-4,共4页Chinese Journal of Geotechnical Engineering

基　　金：湖南省自然科学基金项目(07JJ4015);国家863计划项目(2006AA11Z104)

摘　　要：为探讨未打穿砂井复合地基处治软土时的承载机理与固结特性,基于相似理论设计并完成了未加固软土地基、单桩、三桩及七桩砂井复合地基模型载荷对比性试验,获得了地基的荷载-沉降曲线,以及单桩、三桩及七桩砂井复合地基中桩顶应力分担比及孔隙水压力随荷载的变化曲线。结果表明:砂井复合地基可显著改善软土地基的承载能力与沉降特性,其中单桩复合地基提高承载力可达到60%,且相比之下沉降最小,但存在"群桩效应",如三桩和七桩砂井复合地基承载力分别约为单桩砂井复合地基承载力的73%和58%,故工程中应慎选井距。To study the bearing and consolidation behavior of sand well composite foundation,a group of indoor model loading tests on the untreated soft subsoil and sand well composite foundation with single,three and seven sand drains are designed and completed in terms of the similarity theory.Based on the obtained test data,the load-settlement curve,the stress ratio and the pore water pressure changing curves along with the exerted load at the well top and of sand well composite foundations are discussed.The changing rules of these curves show that,sand well composite foundation can significantly improve the bearing capacity and decrease the settlement of subsoil.As for the single-pile composite foundation,a relative increase of 60% may be achieved in the bearing capacity with a smallest settlement.However,the 'pile group effect' is also found,i.e.,the bearing capacities of the three and seven sand wells composite foundations are equal to 73% and 58% of that of the single sand well composite foundation respectively.This means obvious decreasing of the bearing capacity and increasing of the settlement of composite foundation if more sand wells were included under the bearing plate during the loading test.Therefore,appropriate well spacing should be selected in engineering practice.

关 键 词：复合地基 砂井 模型试验 承载机理 

分 类 号：TU470[建筑科学—结构工程]