Hello, I have to analyse strengh of a thank that is underground. It's completely contrained on concrete at it's bottom and it's stressed by the pressure of the ground (topsoil + water = 1.7 density). What kind of stress I must apply (constant pressure, force...) ? Can someone give me an idea or a link that explain how this should be set ? I know there are several methods to calculate soil pressure (Coulomb, Rankine...) but I don't know how to use them and I don't know what kind of soil it is. Perhaps I could calculate as a tank fixed in a liquid ?