A load-balancing-oriented symmetrical uneven layout design for thrust system in tunneling machines under composite ground

Abstract

Mechanized tunneling is characterized by high automation, efficiency, safety, and environment-friendly during tunnel construction progress. Studies to improve the force transmission performance of the thrust system playing an important role among all sub-systems in shield machine have been conducted recently. In this paper, a new nonequidistant arrangement with load-balancing-oriented ability has been proposed under complex ground. Firstly, the required mechanical functions are derived from the force transmission ellipse model. Secondly, the symmetrical uneven thrust system model has been set up to solve the mechanical functions. Then, all characteristics for the symmetrical shape driving system model have been investigated in detail. Finally, applying the solving model to the thrust system of a shield machine with a diameter 6.28 m, which has been used to construct some tunnels, the comparison of force transmission between the designed uneven thrust system and the even system manifests that the performance for nonuniform driving system is more uniform than the latter. The results also proved that nonequidistant thrust system with the better transmissibility in force can be preferred under some mixed ground.