敞口混凝土管桩土塞形成机理与荷载传递

项目名称： 敞口混凝土管桩土塞形成机理与荷载传递

项目编号： No.41502304

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 地质学

项目作者： 刘俊伟

作者单位： 青岛理工大学

项目金额： 21万元

中文摘要： 土塞效应显著影响敞口混凝土管桩的贯入和承载特性。本项目拟结合室内模型试验、数值仿真模拟及理论分析，对敞口混凝土管桩土塞形成机理与荷载传递特征开展系统研究。具体内容包括：（1）通过可视化双壁模型桩试验和恒刚度界面剪切试验，研究沉桩及加载过程中土塞的细观演变和宏观力学响应，揭示多工况多因素下土塞的形成机理和工作机制，建立细观参数与宏观力学指标的关联；（2）考虑土颗粒的破碎及内壁的磨损，基于室内试验结果建立颗粒流仿真模型，揭示沉桩方式、截面尺寸及土层分布对土塞效应的影响规律；（3）考虑残余应力的影响，基于试验及数值分析成果，构建并解答敞口混凝土管桩荷载传递理论模型，建立土塞对敞口混凝土管桩贯入及承载性能影响机制的函数表达。研究成果将为敞口混凝土管桩的设计和施工提供理论依据。

中文关键词： 敞口混凝土管桩；土塞；荷载传递；桩基贯入；残余应力

英文摘要： Soil plug has a marked impact on the installation of open-ended concrete pipe pile and its bearing capacity. This project proposes a systematic study on the soil plug formation mechanisms and load transfer characteristics related to open-ended concrete pipe pile through combining laboratory model tests, numerical calculation and theoretical analysis. Main research content includes: (1) Based on visualized double-skinned model pile tests and constant normal stiffness direct shear tests, study is carried out on the microscopic developments and macro mechanical responses of soil plug during pile sinking and loading with a view to revealing the formation and working mechanisms of soil plug under different influence factors and establishing the correlation between the microscopic parameters and macro mechanical index; (2) Considering soil particle crushing and the wear of inner wall of pile, the particle flow is simulated numerically based on the laboratory test results to reveal the influences of installation method, section dimension and soil distribution on the soil plug effects; and (3) Taking the residual stress into account, the load transfer model of open-ended concrete pipe pile is established and resolved on the basis of test and numerical analysis results, and a regression equation will be established to express the influence of soil plug on the characteristics of pile installation and bearing capacity. The research results shall provide theoretical references for the design and construction of open-ended concrete pipe pile.

英文关键词： Open-ended concrete pipe pile;Soil plug;Load transfer;Pile installation;Residual stress