海洋平台桩基的打桩分析-岩土工程专业论文.docxVIP

阻力难以准确的确定。为了解决这一问题，本文选用有限单元法和波动方程分析 阻力难以准确的确定。为了解决这一问题，本文选用有限单元法和波动方程分析 法对打桩过程进行了研究。 首先，简述了动力有限元的基本理论，利用有限单元法模拟了在砂土层和粘 土层中的打桩过程，分析了锤击力和土性参数(弹性模量、泊松比、摩擦角和粘 鸱，●一 聚力)对打桩的影响；研究了连续打桩时桩周土体的位移场、应力场以及超孔隙 水压力的变化；讨论了砂土中土的固结过程对打桩的影响；还对打桩造成粘土强 度降低的机理和影响因素进行了分析。 其次，阐述了波动方程分析法的基本原理及其数值求解方法，并在简要介绍 波动方程分析软件GRLWEAP的基础上，对应用GRLWEAP进行打桩分析时主 要参数的选取方法进行了总结。 最后搜集了渤海海域海洋石油开发工程中的36根钢管桩的打桩记录，以这 些实际工程资料为依据进行分析，总结了不同土层中土阻力的变化特点。根据实 际的打桩记录，利用波动方程反分析法确定了打桩时粘土层和砂土层中的土阻 力，并与用现有方法计算得到的土阻力进行了对比，最终对打桩过程中土阻力的 确定方法进行了改进，并以工程实例对该方法进行了验证。 关键词：钢管桩，土gfl力，有限单元法，PLAXIS，波动方程法，GRLWEAP ABSTRACTAs ABSTRACT As a result of large diameter super long steel pipe piles and poor construction environment,pile installation is very difficult in the offshore platforms．Prediction of pile drivability is an essential link before pile construction．In actual projcots，wave equation method is often used to analyze pile drivability．As it is difficult to accurately determine the soil resistance to driving，there are often some differences between the result of pile drivability prediction and actual pile driving record．To solve this problem，finite element method and wave equation method Were used to study the process of pile driving． 寸．1j Firstly,the basic theories of dynamic finite element method Were briefly introduced．Finite element method was used to simulate pile driving process in sand and clay．The influence of impact force and soil parameters Was analyzed．The variation of displacement field，stress field and extra pore water pressure around the pile were studied during continuous pile driving．The influence of consolidation in sand is discussed．The mechanism of reduction in clay undrained strength and influence factors during pile driving were analyzed． Secondly,the basic principles and numerical solution of wave equation method were expounded．The GRLWEAP program Was briefly described，and selection methods of the main parameters Were summarized． Finally,pile driving records of 36 steel pipe piles in offshore engineerings in t