【作者】 陈波；

【导师】 闫澍旺；

【作者基本信息】 天津大学 ， 岩土工程， 2003， 博士

【摘要】 海洋桩基平台打桩问题是一个涉及动力学、结构力学、土力学等多学科领域的综合、复杂、系统的研究课题。本文紧密结合大量工程实测数据和我国南海某大型油气田开发所提出的平台超大直径、超长、深贯入桩基的动力打桩可打入性和承载力的高精度预测分析研究课题，同时跟踪本学科前沿领域，对以下几个方面进行了较为深入的探讨和研究。1. 针对实际打桩工程中常忽略桩自由站立稳定性问题，引入三维几何非线性有限元分析方法研究了系统的非线性、桩的倾斜度、桩的自由站立长度以及桩顶水平载荷等因素对桩自由站立稳定性的影响。2. 根据土的非线性和非弹性特性以及室内与现场试验结果，而且基于桩侧土体与桩端土体在竖向荷载作用情况下的变形和破坏机理不同，提出应采用不同土体模型分别模拟桩侧、桩端土体在打桩过程中所发挥的静阻力，即：建立了桩侧土体双曲线模型，并推导了桩端土体理想弹塑性模型。3. 土塞对大直径、超长桩的可打入性有重要影响，而桩径大小直接影响土塞特性，本文建立了大直径（超大直径）、超长、深贯入桩土塞闭塞效应判断方法和土塞非线性双曲线计算分析模型，并提出了“内侧极限摩阻力动态分布” 模式。4. 基于上述模型，以一维应力波为基本理论编制出打桩分析程序ADP，并采用多项打桩工程实例进行验证分析。5. 将ADP程序应用于多项实际工程中。更多还原

【Abstract】 Pile driving in offshore platform foundation is a synthetic、complex and systemic research involved subjects such as dynamics, structure mechanics and soil mechanics. Based on the data of pile driving records of a great number of piles in offshore platforms and the project about driveability analysis of super large diameter, super length, deep penetration pile of one oil-gas field in our South Sea，simultaneously, following up the front of the research of pile driving, studies have been performed as followings: 1. The stability of pile stick-up is usually ignored in practical engineering of pile driving. Numerical stimulation analysis for stability of pile stick-up with geometrical nonlinear 3-D finite element method (FEM) in pile foundations of offshore platform was performed. i.e., the effect of Linear and nonlinear analysis, the gradient of pile, the length of pile stick-up, and the horizontal force on the stability of pile stick-up were studied in details. 2. Based on the difference of deformation and failure mechanism for pile side soil and pile toe soil, soil mechanics theory, and results of laboratory experiments and field tests, hyperbolic model and ideal elastic-plastic model were proposed to describe the behavior of the soil adjacent to the pile shaft and the soil at the pile toe, respectively. And the hyperbolic model was established. 3. The soil plug has an important effect on the pile driveability, and the pile diameter has an important effect on the property of soil plug, too. Then the plugged effect judging method and nonlinear model of soil plug of the large ( super large ) diameter, super length, deep penetration pile have been established. Hyperbolic model of soil plug was also proposed to calculate the inside static resistance. And the mode of dynamic distribution of inside extreme static resistance was firstly proposed. 4. Based on the above hyperbolic model for the shaft soil and the soil plug, 1-D stress wave theory and Smith method, a program of analysis driving pile (ADP) was<WP=4>developed and applied in calculation of piling in several offshore platform foundation engineering. The results show that the program can be used to study on the large (super large), super length, deep penetration pile driveability and bearing capacity.5. The prediction analysis of pile driveability and bearing capacity in several projects was performed with the ADP program.更多还原