Table 1.

Input feature description and feature selection results.

Input features	Feature description	Feature selection
Total thrust	The total thrust of the jacks during tunneling. It reflects the load of the shield (KN)	√
Advance speed	The speed of the shield when tunneling (mm/min)	√
Cutter disk torque	The torque of the Cutter disk when spinning (N˙m)	√
Earth pressure	The value of the earth pressure sensor in the soil compartment (bar)	√
Shield rear slope	The value of the angle sensor of the rear shield (°)	√
Segment slope	The slope of the last segmental ring (°)	×
Slope variance	The variance of the shield rear slope within an interval	√