Vertical shaft type tailrace surge chamber adit excavation construction method

The invention discloses an adit excavation construction method for a vertical shaft type tailrace surge chamber. The vertical shaft type tail water surge chamber comprises a top arch, a middle partition wall, a left surge chamber body and a right surge chamber body, the left surge chamber body and the right surge chamber body are formed through separation of the middle partition wall and arranged in parallel, an adit excavation construction method is adopted for excavation, layering is conducted from top to bottom, and each layer is excavated in a partitioned mode; during excavation, a zigzag temporary slope ramp is arranged, and a tail adjusting middle adit, two middle partition wall connecting holes and a tail adjusting lower adit are arranged to serve as communicating channels of all surge chambers and the outside; the maximum gradient of the zigzag temporary slope ramp is less than 17%; according to the construction method, the problem that the slag slipping wellhead is difficult to protect is solved, the