Pit rock blasting excavation construction method

The invention relates to a pit rock blasting excavation construction method. The method is characterized in that: from the center of a spiral flow tank to the periphery, layered construction is performed sequentially in three modes of groove blasting of a middle grooving part, peripheral rock blasting and smooth surface blasting of a pit wall; grooving is implemented at the central part of the tank to perform groove blasting on the middle grooving part; after a middle groove is formed, loose blasting control is performed on the peripheral rock part; and when the construction is pushed to a reserved smooth blasting layer part, the smooth surface blasting process is adopted for construction. By adopting the method, the construction is convenient, the blasting damage effect is effectively controlled, the flying rock is controlled in a pit during blasting, and construction safety is ensured; the rock stability of the pit is ensured; the surrounding wall surface is smooth and complete; the blasted rock is small and convenient for digging; and the consumption of an explosive material is saved by about 20 percent, the mechanical cost (about a machine team, oil and the like) is saved, the labor cost is saved by 10 percent, and the protective cost is reduced by using a closed tent.