Stability investigation of buried horizontal tank

Key words:  buried storage tanks  radial pressure  tangential pressure  eigen value buckling  critical depth

Abstract:

The loading conditions are very complex for the buried horizontal storage tank, and therefore it is difficult to calculate its stress and deformation accurately. Based on the real loads of the pressure vessel, the finite element model on the stability of the tank was built. Non-linear radial and tangential forces were adopted to describe the casing pressure of the tank with a given depth, and buckling analysis of the tank model was carried out by the ANSYS software. The eigen values obtained by the buckling analysis were used as iteration parameters to calculate the new buried depth of the tank, and the new buckling analysis is made with the updated data. The result shows that the calculation method of the critical buried depth on the instability of the tank can be used to perform the analysis of tank buckling. The eigen value from series of buckling analysis comes close to the value of one, and in this case the corresponding buried depth is just the critical in stability value. It indicates that adding a strengthening ring can enhance the stability of the buried tank, which can provide enough safety margin for the design of tanks with a big buried depth.