海洋结构物动土压力研究

发布时间：2018-05-09 10:42

本文选题：被动土压力 + 速率影响系数　；参考：《天津大学》2016年硕士论文

【摘要】：随着人类逐渐加大对深海能源的开发利用,大量的基础设施需要建立在深海领域,包括海底输油管线和船舶锚泊系统等,这些结构物的运动位移远远大于自身尺寸。传统的岩土工程基础设计主要针对陆上的静态建筑物,并不适用于深水环境中的这类结构物。结构物受到的动土压力与结构物运动速率、埋置深度以及几何形状等因素相关,因而结构物与土相互作用机理变得十分复杂,这就需要研究新的计算方法来确定运动中结构物受到的土压力。本文首先开展了拖板模型试验,在此基础上通过DEM数值模型模拟分析,取得了如下试验结论和研究成果:1.拖板模型试验表明,任一拖板速率下,运动中平板受到的土压力变化发展均分为四个阶段,首先是土压力缓慢增长阶段;第二阶段是土压力迅速增长阶段;第三阶段可理解为由土拱效应引起的缓慢增长阶段,此阶段内土压力达到峰值;最后是稳定发展阶段。相同埋置深度下,平板受到的土压力随拖板速率增加而增加;相同拖板速率下,平板受到的土压力随埋置深度增加而增加。2.用朗肯土压力计算平板受到的静止土压力和被动土压力,并将得到的计算值与试验测得的土压力值进行比较,证明运动的结构物受到的土压力用朗肯土压力理论计算是不合理的。在模型试验和前人总结的理论公式基础上,拟合出土压力关于结构物运动速度的速率影响系数和关于结构物埋置深度的深度影响系数。同时引入离散单元法,重点介绍了离散元的基本原理、理论以及解决土压力问题的可能性与优势。3.建立三维DEM数值模型模拟拖板模型试验,DEM模型计算的土压力变化规律与试验结果比较吻合,验证了DEM模型能较好模拟运动结构物受到的土压力变化规律。4.通过DEM模型,进一步验证了结构物运动速率和埋置深度是影响受挤压土体的土压力的重要因素。
[Abstract]:With the increasing development and utilization of deep-sea energy, a large number of infrastructure needs to be built in the deep sea field, including submarine oil pipelines and ship mooring systems, and the moving displacement of these structures is much larger than their own size. The traditional geotechnical engineering foundation design is mainly aimed at static buildings on land and is not suitable for such structures in deep water environment. The dynamic earth pressure of the structure is related to the moving rate of the structure, the depth of the structure and the geometric shape, and so on, so the interaction mechanism between the structure and the soil becomes very complicated. Therefore, a new calculation method is needed to determine the earth pressure on the structure in motion. In this paper, first of all, the trailing plate model test is carried out, and on the basis of this, the DEM numerical model simulation analysis is carried out, and the following experimental results and research results are obtained as follows: 1. The results of trawl model test show that the variation and development of the earth pressure on the plate is divided into four stages: the first stage is the slowly increasing stage of the earth pressure, the second stage is the stage of the rapid growth of the earth pressure, the second stage is the rapid growth stage of the earth pressure. The third stage can be understood as the slow increasing stage caused by the soil arch effect, in which the earth pressure reaches its peak value, and finally the stable development stage. At the same embedding depth, the earth pressure on the flat plate increases with the increase of the trawl speed, and the earth pressure on the flat plate increases with the increase of the buried depth at the same trailing rate. The static earth pressure and passive earth pressure are calculated by Rankine earth pressure, and the calculated values are compared with the measured earth pressure values. It is proved that the calculation of the earth pressure of moving structures by Rankine earth pressure theory is unreasonable. On the basis of model tests and theoretical formulas summarized by predecessors, the coefficient of influence of unearthed pressure on the velocity of structure motion and the coefficient of depth of buried depth of structure are fitted. At the same time, the discrete element method is introduced to introduce the basic principle of discrete element, the theory and the possibility and advantage of solving the earth pressure problem. Three dimensional DEM numerical model was established to simulate the variation law of earth pressure in Dem model. It is verified that the DEM model can well simulate the variation law of earth pressure of moving structure. Through the DEM model, it is further verified that the velocity of structure motion and the depth of burial are the important factors affecting the earth pressure of squeezed soil.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：P75;TU432

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