自升式平台仿生桩靴设计与作业评估

发布时间：2018-04-26 00:30

本文选题：自升式平台 + 螺壳　；参考：《江苏科技大学》2017年硕士论文

【摘要】：现役自升式平台存在桩土连接刚度低、刺穿和滑移事故率高、拔桩阻力大等问题,无法满足钻井作业深水化趋势及工作安全性要求。为此,提出“复合仿生”理念,基于螺壳独特的膨胀层特性和蛋壳优异的流线型结构,开展自升式平台仿生桩靴设计与作业评估,具体研究内容如下:(1)以螺壳表面螺旋部、缝合线以及蛋壳轮廓形状为基础,开展轮廓扫描试验,分别对两者的形状特征进行统计;通过Hypermesh软件提取特征点,利用Origin软件推导并拟合出符合要求的两种螺旋线、体螺层曲线以及蛋壳轮廓线的数学表达式;最后结合Matlab软件和皮尔逊相关系数对拟合出的曲线进行验证,保证曲线与生物原型的高度吻合。(2)通过分析现有的桩靴承载力理论公式,研究单层、多层地基的插桩阻力;接着运用孔扩张理论推导出基于SMP准则的插桩阻力,并与土工试验进行对比;然后分析国内外拔桩阻力的理论公式;最后对理论公式在实际应用和仿生桩靴中的可行性进行分析。(3)结合体螺层特点及函数,构建桩靴下半部分的螺壳形仿生模型;结合蛋壳钝端特点及蛋形函数,构建桩靴上半部分蛋形仿生模型。研究螺壳形仿生模型与蛋形仿生模型之间的复合机制,进而建立“螺壳-蛋壳”形桩靴复合仿生模型。运用仿生桩靴与土壤耦合力学行为分析方法,利用Abaqus数值分析方法,分析“螺壳-蛋壳”形仿生桩靴插桩工况下的插桩载荷与深度的定性关系。最后在后处理过程中研究插桩工况下土壤流动失效模式,并分析土壤流动失效对插桩载荷的影响机制。(4)利用Abaqus数值分析方法,在不考虑渗流-应力耦合情况下研究拔桩阻力变化,并与在渗流-应力耦合情况下的插桩阻力进行对比。其次,通过有限元方法,研究两种桩靴上下表面的孔隙压力变化;最后,研究拔桩工况下土壤流动失效模式,并分析土壤流动失效对拔桩载荷的影响机制。
[Abstract]:There are some problems such as low stiffness of pile-soil connection, high accident rate of puncture and slip, and large resistance of pulling pile, which can not meet the requirements of deepwater drilling operation and safety. Therefore, the idea of "composite bionics" is put forward. Based on the unique characteristics of the expansion layer of the shell and the excellent streamlined structure of the shell, the design and operation evaluation of the bionic pile boots of the jack-up platform are carried out. The specific research contents are as follows: 1) the helical part of the spiral surface of the spiral shell. On the basis of suture line and eggshell contour shape, the contour scanning test is carried out, and the shape characteristics of the two lines are statistically analyzed. The feature points are extracted by Hypermesh software, and the two helical lines that meet the requirements are deduced and fitted by Origin software. The mathematical expressions of the snail curve and the eggshell contours are given. Finally, the fitting curves are verified with Matlab software and Pearson correlation coefficient. By analyzing the existing theoretical formulas of bearing capacity of pile boots, the pile insertion resistance of single-layer and multi-layer foundation is studied, and then the pile insertion resistance based on SMP criterion is derived by using the hole expansion theory. And compared with the geotechnical test, then analyzed the theoretical formula of pulling pile resistance at home and abroad, finally analyzed the practical application and feasibility of bionic pile boots. The snail shell bionic model of the bottom half of the pile shoe is constructed, and the egg shape bionic model of the upper half of the pile shoe is constructed by combining the characteristics of the shell blunt end and the egg shape function. The composite mechanism between the snail shell bionic model and the eggshell bionic model is studied, and the composite bionic model of the "snail shell-eggshell" pile shoe is established. By using the method of bionic pile boots and soil coupling mechanical behavior analysis and using Abaqus numerical analysis method, the qualitative relationship between the load and the depth of the inserted pile under the condition of "screw shell and eggshell" type bionic pile boots was analyzed. Finally, the failure mode of soil flow under the condition of pile insertion is studied in the post-treatment process, and the influence mechanism of soil flow failure on the load of pile insertion is analyzed. (4) Abaqus numerical analysis method is used. The variation of pile pulling resistance is studied without considering seepage and stress coupling and compared with that of pile insertion under seepage stress coupling. Secondly, the change of pore pressure on the upper and lower surface of two kinds of pile boots is studied by finite element method. Finally, the failure mode of soil flow under the condition of pile pulling is studied, and the influence mechanism of soil flow failure on pile pulling load is analyzed.
【学位授予单位】：江苏科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU473.1

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