How to retrieve the drill bit when it falls into the well:

The manual fishing method uses 3 pieces with a diameter of Φ 28 80m long steel wire rope, along the diameter Φ The steel casing with a length of 2.0m and 7.2m is uniformly distributed, and the lower opening is made into a circular shape and fixed with iron wire at the bottom of the casing. Vertically and smoothly hoist the steel casing, and the diver descends to the top surface of the circular counterweight. A circular hole is made at the upper end of the drill pipe, a steel wire rope is threaded, and both ends of the steel wire rope are led out of the casing, and then the drill bit is lifted. Due to the thick mud and sand layers of the bridge, the hole is prone to collapse. According to mechanical principles, using the difference in friction between the inside and outside of the inclined plane, when the fishing tool is inserted into the drill collar and lifted upwards, the fishing tool supports the inner wall of the drill collar tightly and then lifts it as a whole.