Measurement and enhancing prediction of EPBM torque using actual Machine data

Abstract

The cutterhead torque of an Earth Pressure Balance Machine (EPBM) plays a critical role in determining the performance of mechanized tunneling in urban areas. However, as this parameter is not directly set by the operator but is a function of geological conditions, thrust force, screw conveyor revolution speed, and soil conditions, it is closely linked to geotechnical parameters and machine settings. Despite previous attempts to predict EPBM torque using Shi's physical model, accuracy has been lacking. This study aims to improve the accuracy of this prediction by utilizing actual data from an EPBM used in a metro line tunneling project to identify the primary factors influencing torque and to modify related equations accordingly. To evaluate the performance of existing models and the predictions made by the presented method, various metrics are utilized, including the correlation between all torque values, the relationship between torque and thrust values, and the connection between thrust pressure and penetration. The results indicate that in addition to geotechnical parameters, machine settings such as thrust force, cutterhead revolution speed, arching pressure, soil conditions, and chamber pressure significantly impact the torque value. The study found that the thrust force exerted by the EPBM is a key factor influencing torque.