Determination of undrained shear strength using piezocone penetration test in clayey soil for bridge foundation  

桥梁基础工程中基于CPTu的粘性土不排水抗剪强度确定方法(英文)

作　　者：童立元[1] 王强[1] 杜广印[1] 刘松玉[1] 蔡国军[1] 

机构地区：[1]东南大学交通学院,南京210096

出　　处：《Journal of Southeast University(English Edition)》2011年第2期201-205,共5页东南大学学报（英文版）

基　　金：The National Natural Science Foundation of China(No.40702047)

摘　　要：In order to obtain the reasonable undrained shear strength Su for geotechnical analyses of bridge foundations in Yangtze River floodplain clayey soils, a site-specific study is conducted using the imported piezocone penetration test （CPTu） with dissipation phases at the Fourth Nanjing Yangtze River Bridge construction sites. Taking the values of Su from laboratory tests as references, several existing Su-predicted methods based on CPTu are compared and evaluated. To verify the presented cone factor Nk, additional test sites are selected and examined. The results show that the values of cone factors such as Nkt, Nke, and Nau, depend on the shear test mode and disturbance. Generally, the values of Nke show more scattering than those of Nkt and N△u. For the stratified and layered sediments of the Yangtze River floodplain, it is recommended using the net cone resistance qT to estimate Su and the preliminary cone factor values Nkt are from 7 to 16, with an average of 11. It is also confirmed that the CPTu test, as a new technique in site characterization, can present reasonable parameters for bridge foundations.为了给南京长江四桥基础工程设计与分析提供可靠的长江漫滩粘性土不排水抗剪强度Su参数,采用国外引进的孔压静力触探(CPTu)测试系统进行了现场原位试验,并以高质量土样的室内试验作为参考,对几种基于CPTu的Su确定方法进行了对比与评价,同时对所提出的圆锥系数Nk值进行了验证.试验结果表明:圆锥系数Nkt,Nke,NΔu的大小取决于剪切试验模式及试验扰动程度;Nke一般比Nkt,NΔu表现出更大的离散性;对于长江漫滩多夹层粘土地基,建议采用净锥尖阻力qt预测Su,相应的圆锥系数Nkt数值在7～16之间,平均值为11;应用CPTu新技术,可以为桥梁基础工程设计提供合理的设计参数.

关 键 词：undrained shear strength piezocone penetrationtest clayey soil cone factor bridge foundation 

分 类 号：TU413[建筑科学—岩土工程]