Stress Analysis Of Large Tank Under Foundation Settlement

Refined oil storage tanks,as a refined oil reserve facilities,the major trend in the development of storage tanks is large-scale.Once the refined oil depot had an accident,the consequences could be much more disastrous.Therefore,the research does an in-depth study on the safety and strength of refined oil tank.In this paper,an inner floating-roof oil tank with a capacity of 50000m3 is taken as the research object,the stress distribution on the tank wall and tank bottom,the radial displacement of the tank wall are studied.The paper aimed at the problem:settlement of large tanks.The three-dimensional model of the tank is established by ABAQUS,and the model takes the ring wall foundation,the tank top,tapered wall thickness and the wind girder into account.Firstly,the stress of the tank wall under nonnal working condition is analyzed and compared with the theoretical calculation value,the results show that the model has high accuracy.Then,by changing the width of the outer edge of the tank bottom and the width of the ring wall,a more suitable width of the outer edge plate and the width of the ring wall are proposed.Secondly,analyze the stress distribution of the tank wall and the tank bottom under the inclined settlement.The stress intensity at the shell-to-bottom fillet welds will reach the permissible stress first,but the effect on tank wall is small.Thirdly,analyze the stress distribution of the tank under harmonic settlement.The harmonic settlement function is obtained by Fourier decomposition.Analyze the effects of single harmonic on the tank wall and tank bottom.Changing the harmonic order,the amplitude of hannonic settlement and the liquid level,by means of stress evaluation of the tank wall and tank bottom,figure out the dangerous position of the tank under single harmonic settlement,and then obtain the critical sedimentation amplitude.Then,propose the angle of the fillet weld,the stress at the inner fillet weld is effectively reduced,the safety of the tank is improved.Finally,consider the variation of the radial displacement of the tank wall under the settlement,the critical sedimentation amplitude of the tank is detennined by the stress distribution of the tank and the radial displacement distribution of the tank wall.Then,analyze the change rule of radial displacement of the tank wall under the single harmonic settlement.Consider the displacements of different settlement amplitude,different liquid level and different height of tank wall,determine that full load has a greater effect on the radial displacement.Then fit the calculation formula of the radial displacement of the tank wall at the highest level under single harmonic settlement and the superposition of harmonics settlement.Simulate the displacement of the tank wall under the superposition of harmonics settlement by the finite element method,and the relative coincidence degree of the two is better.So the fitting formula has a significant reference value and guiding significance to the engineering practice.