大型LNG储罐高承台桩基沉降特性及隔震效果分析

发布时间：2018-03-10 22:26

本文选题：大型LNG储罐　切入点：桩基　出处：《河北农业大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着我国经济的飞速发展,资源需求的快速膨胀,高效环保型LNG能源在我国已经得到了广泛应用。为保障我国LNG的供应和储备,我国大多采用大型LNG储罐对其进行存储。大型LNG储罐具有大直径、大体积、质量大等特点,对地基基础要求较高。在大型LNG储罐工程建设中基础建设尤为重要。本文依据天津某LNG接收站工程实例,采用岩土工程专业数值模拟软件FLAC3D建立数值模型,模拟桩基工作原理,分析桩基工作性质。从大型LNG储罐下桩基沉降计算方法、布桩方式、隔震设计三方面进行优化分析,并提出可行的合理化建议,为今后类似工程提供经验和参考。在查阅国内外大量文献的基础上本文所做工作如下:(1)总结国内外常用的桩基沉降计算方法,并进行分析与评价。采用等代墩基法、修正等代墩基法、荷载传递法、对桩基沉降进行计算,建立FLAC3D数值模型,模拟桩基沉降,最终得出模拟沉降结果。(2)采用变刚度调平设计理念,通过改变桩长、桩距等方法调整桩基不均匀沉降。运用岩土工程专业数值模拟软件FLAC3D建立两组大型LNG储罐高承台桩基调平方案。分析得出:两组不同方案下桩基沉降均呈现内大外小的“碟型”分布特征,与以往经验相吻合。增加桩长可以有效的减小桩基沉降,对桩基不均匀沉降作用效果较小。非等间距布桩下,局部加强结合长短桩布桩方式不但有效的减小了群桩基础的沉降量,在控制差异沉降中也有明显的效果,为最理想的变刚度调平方案。(3)分析实际地震记录天津波、唐山波、EL-Centro波和Taft波作用下,加入隔震设计前后承台位移变化和速度变化。加入隔震垫的承台位移峰值和速度峰值有明显下降趋势。其结果充分说明了隔震层起到了很好的隔震效果,大幅度减小了承台的地震响应。
[Abstract]:With the rapid development of China's economy and the rapid expansion of resource demand, efficient and environment-friendly LNG energy has been widely used in China. In China, large LNG tanks are mostly used to store them. Large LNG tanks are characterized by large diameter, large volume and large quality. The foundation is very important in the construction of large LNG storage tank. According to the example of a LNG receiving station in Tianjin, the numerical model is established by using the numerical simulation software FLAC3D of geotechnical engineering, and the working principle of pile foundation is simulated. The working property of pile foundation is analyzed. The settlement calculation method of pile foundation under large LNG storage tank, pile layout method and isolation design are optimized and analyzed, and some feasible rational suggestions are put forward. It provides experience and reference for similar projects in the future. On the basis of consulting a large number of literatures at home and abroad, the work done in this paper is as follows: 1) summing up the common calculation methods of pile foundation at home and abroad, and analyzing and evaluating them. Modified equivalent pier foundation method, load transfer method, calculate pile foundation settlement, establish FLAC3D numerical model, simulate pile foundation settlement, finally get simulated settlement result. Finally, adopt variable stiffness leveling design idea, by changing pile length, The non-uniform settlement of pile foundation was adjusted by means of pile spacing and other methods. Two groups of large LNG storage tank high cap pile foundation leveling schemes were established by using the numerical simulation software FLAC3D of geotechnical engineering. It was concluded that the settlement of pile foundation in two groups of different schemes showed a large internal size. Small "disc" distribution, In accordance with previous experience, increasing pile length can effectively reduce the settlement of pile foundation, and has little effect on uneven settlement of pile foundation. The method of local strengthening combined with long and short piles not only effectively reduces the settlement of pile group foundation, but also has obvious effect in controlling the differential settlement. It is the most ideal leveling scheme of variable stiffness to analyze the actual seismic recorded Tianjin wave. Under the action of EL-Centro wave and Taft wave, Before and after the design of isolation, the displacement and velocity changes of the cap are changed. The peak displacement and velocity of the cap with the isolation cushion have an obvious downward trend. The results show that the isolation layer has a good isolation effect. The seismic response of the cap is greatly reduced.
【学位授予单位】：河北农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU473.1;TU433

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