Main drive turn-over device and method for super-large-diameter shield tunneling machine

The invention discloses a main drive turn-over device and method for a super-large-diameter shield tunneling machine. The main drive turn-over device comprises an arc-shaped turn-over base, and turn-over parts mounted at the two ends of the turn-over base. The main drive turn-over method comprises the following steps: the lower part of a shield body block serves as the turn-over base; an upward turning part is lifted; lifting lugs are connected for turning over; after a main drive rotates by 90 degrees, hook replacing operation is conducted; after hook replacing is successful, turning over continues; when the main drive rotates by 180 degrees, after a motor and a speed reducer are mounted, lifting hooks are connected, and two lifting parts reversely act till the main drive is located in the vertical position; and the main drive is lowered through hydraulic oil cylinders on the two sides. Previous overall lifting turning-over operation of the main drive is cleverly converted into rotation turning-over operatio