基于离心试验的斜顶桩接岸结构负摩阻力研究

Research on Negative Skin Friction in Inclined Pile Link-banked Structure Based on Centrifugal Test

上海洋山港高桩码头后方接岸结构采用斜顶桩接岸结构,目前对该结构中斜顶桩、板桩的负摩阻力鲜有研究,且缺乏对负摩阻力主要产生原因的认识。为对接岸结构中各桩负摩阻力特性有较全面的认识,通过简化边界条件建立概化物理模型,利用土工离心试验来实测接岸结构在特定条件下的变形和受力情况。根据相关资料和试验数据,着重分析了结构和土体变形,进而分析各桩轴向力和负摩阻力沿桩深分布规律,并对负摩阻力产生的主要原因进行阐述,最后采用原型观测验证物模结果。试验研究结果表明:接岸结构各桩均在桩身一定范围内产生负摩阻力,其中性点位置与桩长比例范围约为0.63~0.75;且软黏土固结是斜顶桩接岸结构中桩基负摩阻力产生的主要原因。

Inclined pile link-banked structure is used as a kind of retaining structure behind the high-piled wharf in Shanghai Yangshan harbor, in which there is little research on negative skin friction of inclined support pile and the sheet pile and its＇ main producing reason at present. In order to acquire a comprehensive understanding of negative skin friction＇ s characteristics about different kinds of piles,geotechnical centrifugal test is selected to survey this structure＇ s deformation and stress distribution under certain conditions by simplifying boundary conditions and establishing generalized physical model. According to relevant information and test data, the deformation of structure and soil, along with the distribution of axial force and side friction along the depth of different piles are emphatically analyzed in this experiment. Besides, the main producing reason of negative skin friction is explained. Finally, prototype measurement is used to verify the outcome of physical model. The results show that negative skin friction appears within the scope of each pile and the ratio range of neutral point and pile length is about 0. 63 ~ 0. 75. What＇ s more, the consolidation of soft clay is the main producing reason of negative skin friction in inclined pile link-banked structure.