Abstract: A mechanical modelof the earth pressure balance shield screw conveyor is built byconsidering the earth pressure balance. An expression of thepressure at the bottom of the screw conveyor is obtained according to themodel. The relationships between the bottom pressure and theparameters of the screw conveyor and the residual soil are discussed. The expressionprovides a simple method to design, improve, select and evaluate the earthpressure balance shield screw conveyor.