Study On The Sloshing Problem Of Large Vertical Storage Tanks Nnder Long-period Earthquakes

Vertical storage tanks were widely used in the petrochemical industry.With the development of the petrochemical industry and the implementation of the national petroleum strategic reserve,the design and construction of vertical storage tanks is increasing.Large vertical storage tanks are usually used to store flammable,explosive,and toxic media.If they occur under the action of earthquakes,they will cause secondary disasters such as fires and leaks,posing a threat to personal safety and the living environment.The sloshing problem of large vertical storage tanks under earthquake action is an important indicator of seismic design of storage tanks.Whether the design of this index is reasonable is directly related to the safety performance of storage tanks under earthquake action.At the present stage,the wave height calculation in the seismic specification of the storage tanks in the world,the multi-pair short-period periodic ground motion is fortified,and the wave height under the long-period ground motion excitation is small.In view of this,this paper will select ground motions with different spectral characteristics as seismic excitation to study the sloshing effect of the reservoir under its action.With the comparison of national tank specifications,shaking table test and numerical simulation as the support,the sloshing effect is studied,and the wave height under the action of long-period ground motion is revised.The specific research contents are as follows:1.From the theoretical traceability,the fortification benchmark,the fortification target,the site division,the response spectrum,etc.,a systematic comparative analysis of the seismic specifications of storage tanks at home and abroad was carried out,and the sloshing wave height of each standard was calculated,and the Chinese standard was compared with the United States and Japan.In Europe and other countries,the calculation value of wave height is too large,and its value is mainly for the fortification of wave and medium-period ground motion excitation wave height,and the defense of long-period ground motion is insufficient.2.Through the vibration test of the specific tank type,the correlation between the sloshing wave height and the ground motion period parameters and the peak acceleration is obtained.The finite element software ADINA is used to simulate the sloshing of the model tank,and the simulation wave height and the test wave height have a good fit.Both can verify each other.3.The numerical analysis of the sloshing of the 10000m~3 vertical storage tank is carried out,and the relationship between the liquid storage ratio and the peak acceleration of the ground motion and the wave height is discussed respectively.At the same time,the sloshing of the reservoir by the wavefront vibration analysis is the result of superposition of the multi-mode.The sloshing numerical simulation under a large amount of ground motion is used to characterize the wave height with the excellent period as the ground motion period parameter,and the Chinese standard wave height and the simulated wave height are compared to obtain the Chinese standard wave height calculated value for the long period.The envelope rate of the ground motion excitation wave is low,and it is necessary to consider the adverse effects of long-period ground motion on the tank wave height design.4.The long-period ground motion is defined by different methods.From the occurrence probability of long-period ground motion,and the comparison of its response spectrum and norm spectrum,the root mean square method and mode decomposition reaction spectrum method are proposed to lengthen the Chinese standard wave height formula.The cycle correction and adjustment of the double damping correction problem in the wave height formula of GB 50341-2014"Design Specification for Vertical Cylindrical Steel Welding Oil Tank"has certain reference significance for the wave height design of the actual engineering neutral storage tank.