Determination of thrust force for shield tunneling machine

Various influential factors related to determining thrust force were analyzed in order to reduce the uncertainties existing in determination of total thrust force of shield tunneling machine by traditional method. All resistance forces acted on a metro shield machine with 6 m diameter were calculated, and the approximate calculation model composed of several components was given by neglecting the minor components. Experiments were conducted on an earth pressure balanced shield test rig. Results show that earth pressure plays a key part in thrust force calculation, regardless of in clay and sandy soil. Cutting ratio and a relationship with thrust force were developed to establish a more accurate model based on two important factors of earth pressure and cutting ratio.