Mining method construction interval air shaft air duct and method for breaking shield tunnel duct pieces

The invention discloses an air shaft duct and method for breaking shield tunnel duct pieces in a mining method construction interval. The method comprises the steps that the air shaft duct is transversely excavated on one side of an existing shield tunnel; excavating air shafts and air ducts by using a step method according to pilot tunnel numbers in a layered and segmented manner, and constructing a primary support; the upper-layer pilot tunnel is constructed above the top of the tunnel, transversely crosses the existing tunnel and is excavated to a first air shaft air duct end wall A for blocking, and the lower-layer pilot tunnel is constructed below the top of the tunnel, transversely excavated to a second air shaft air duct end wall B close to the outer edge of the shield tunnel for blocking; constructing a waterproof layer and a secondary lining structure of the air shaft duct; a first vertical shaft and a second vertical shaft are excavated on the side edges of the two tunnels in the air shaft air duct