Mining method underground tunnel waterproof curtain and construction method

The invention discloses a mining method underground tunnel waterproof curtain and a construction method. The construction method comprises the following steps: excavating and penetrating through upper layer No. 1 and No. 2 caverns located at an underground water level to construct a primary support structure; downward grouting is conducted at the bottom corners of the two outer sides of the first cavity and the second cavity which penetrate through the first cavity and the second cavity, and a grouting body stretching into the waterproof stratum by a certain depth is formed and serves as wall type waterproof curtains on the two sides; a transverse grouting body is constructed in the direction perpendicular to the excavation direction from the upper layer cavern at a certain distance from the front of the tunnel face, enters the water-proof stratum by a certain depth, serves as a transverse wall type waterproof curtain and is closed with the wall type waterproof curtains on the two sides; underground water in