Analysis Of Stress And Foundation Settlement Of Large Storage Tank

With the development of the petrochemical industry and the implementation of the national strategic oil reserve base project, the inevitable trend for oil storage tank will be large-scale. The large-scale tank also brings about many new problems, such as reducing the tank stiffness, increasing uneven foundation settlement, leading to distortion of bottom plate due to long-term use, increasing the probability of oil leakage due to bottom plate's corrosion and so on. Some of modifications are proposed to solve these problems. And the appearance of the new environmentally-friendly foundation is an important breakthrough. The environmentally-friendly foundation is composed of gravel ring wall foundation and environmental protection technology. It's outstanding feature is that the outer zone of the foundation is higher than the inner zone, so the bottom plate shows like an upset cone. Whereas the typical ring wall foundation usually used for the large storage tank has no environmental protection technology. And the inner zone is higher than the outer zone, so the bottom plate shows front taper. The back taper foundation has been studied and put into use at abroad. However this kind of foundation was adopted in the NanHai petrochemical industry in our country for the first time, and its mechanical properties is not completely understood by us.In this paper 15×10~3m~3 tank is studied with numerical simulation method. And the front taper foundation tank will be contrasted with back taper. Main conclusion are as follows:1,The 2-D axisymmetric finite element model of large storage tank is established with ANSYS software. The constitutive relationship of subgrade soil is simulated by DP elastoplastic model, and the relationship between tank and foundation adopts contact model.2,The static analysis of tank is done for the comparison of front taper foundation with back taper. It shows that the stress of back taper bottom plate is more smaller than the front taper bottom plate, and the slope of the bottom plate increases after settlement, but the stress of the shell-tot-bottom fillet welds is more bigger. These behaviors could reduce the fold deformation, minish the thickness of the bottom plate. Furthermore the increasing slope is beneficial to environment, because the oil leakage flows to recovery well with help of gravity.3,The influence of the parameter is analyzed for the two type tank, which includes tank parameter, foundation parameter and subgrade parameter, etc.