International Core Journal of Engineering 2020-26 | Page 53

2019 International Conference on Artificial Intelligence and Advanced Manufacturing (AIAM) Computer Simulation Model on Tank’s Foundation Settlement Zhao Yongtao Lin Yuming Safety Technology Research Institute CNPC Research Institute of Safety & Environment Technology Beijing, China E-mail: [email protected] Mechanical and Transportation Engineering College China University of Petroleum (Beijing) Beijing, China E-mail: [email protected] Abstract—Many large oil storage tank bases in China are built among areas along sea, and the foundation of storage tank is vulnerable to settlement, which can cause negative effect on the safety of storage tank. Fourier decomposition method is used to process the actual measured data of storage tank’s foundation settlement, depending on which three different finite element models of storage tank are established for calculation. Based on the result of calculation, the behavior of tank under foundation settlement is analyzed and assessment on three models is made through comparison. Conclusions drawn from the analysis can offer guidance to the maintenance of tank safety. models of storage tanks are established based on the measured settlement data of a 100000m 3 large floating roof tank. The measured sedimentation data were processed using Fourier decomposition to consider the interaction between the tank bottom and the foundation soil. On this basis, the structural response of the tank underground settlement conditions was studied to analyze the stress and deformation of the tank after settlement, and the three models were evaluated by comparison. II. F OURIER DECOMPOSITION OF SETTLEMENT DATA The study on the settlement of storage tank foundation has been carried out by many scholars. After years of research and development, the widely used method is using Fourier decomposition to deal with the settlement data of the tank foundation and then use it for subsequent research. Keywords—safety of storage tank, foundation settlement, Fourier decomposition, finite element model I. I NTRODUCTION With the rapid development of the country’s industry, China’s demand for oil resources is increasing day by day. Oil reserves have begun to enter the national strategic level, and at the same time, the construction of commercial reserve banks has been steadily progressing. The construction of large-scale national reserve banks and commercial reserve banks indicates that China's large-scale crude oil reserve construction has entered a period of rapid development. In 1982, Marr et al. [3] suggested that the method of Fourier decomposition was used to study the settlement of the tank, and it was suggested that it is necessary to analyze the influence of the higher order of harmonic settlement on the structure of the tank. In 1989, Kamyab et al [4] used the Fourier decomposition method for the first time to study the force performance and deformation of the tank under the foundation settlement, which is the actual settlement of the tank is carried out by Fourier series shown in Equation (1). Taking into account the construction costs and operating costs of the reserve pool, many large crude oil reserve bases are currently being constructed in the coastal zone [1] , and most of them are built on soft soils formed by land reclamation. This kind of soft soil has poor soil quality, low strength, and high compressibility, which can easily lead to settlement of the tank foundation. The settlement of the tank foundation will cause the deformation of the tank structure. When the settlement is large, the deformation of the tank caused by this will be large, which may cause the chuck phenomenon [2] , affecting the normal production operation of the tank. In severe cases, the structure of the tank may even be destroyed, causing a leakage accident. Therefore, under the background of the vigorous development of the national large-scale crude oil reserve, it is of great practical significance to conduct in-depth research on the structural response of the tank under the settlement of the foundation. At the same time, the study of the structural response of the tank under the settlement of the foundation provides a valuable reference for guaranteeing the normal operation of the tank and the settlement control of the tank foundation. k u u 0  ¦ u n cos( n M  I n ) (1) n 1 In Equation (1), u 0 represents the overall uniform settlement of the storage tank, u n represents the amplitude of the harmonic settlement of each order, n is the order of harmonic settlement, M is the angle of each point in the tank, and I n is the initial phase angle of the harmonic settlement of every order. Gong et al [5] established a tank finite element model to analyze and study the harmonic orders that need to be taken into consideration after Fourier decomposition of the measured settlement of the tank foundation. It is concluded that the selected harmonic order should be less than or equal to [N/3], where N is the number of horizontal observation points of the tank foundation and [] is a round function. In this paper, three full-scale finite element analysis 978-1-7281-4691-1/19/$31.00 ©2019 IEEE DOI 10.1109/AIAM48774.2019.00013 The actual settlement of the tank can be deduced by 31