Abstract: Nowadays, Rankine’s earth pressure theory is still playing an important role on calculating soil earth pressure. Based on Rankine’s theory, active earth pressure behind the wall is distributed to reach a limit equilibrium state in which the sliding surface of limit soil mass is considered as a cluster of planes. Proceeding from limit equilibrium theory, it is pointed out that the boundary of limit soil mass is a combination of sliding surface and crack section. This proposed sliding-cracking surface, which is in full compliance with Rankine’s theory with regards to active earth pressure distribution and resulting force, can be considered as an actual sliding surface when the soil failure occurs under active earth pressure. On the other hand, Rankine’s theory is applied to evaluate the soil tensile stress behind the wall under passive earth pressure, verifying that the sliding surface of limit soil mass can also be considered as a cluster of planes under passive earth pressure. The study result enhances the application of the Rankine’s earth pressure theory.

Key words: Rankine’s earth pressure theory, limit equilibrium, limit soil mass, sliding surface