Water stopping and leaking stoppage structure and water stopping and leaking stoppage method for lock catch steel pipe pile cofferdam

The invention discloses a water stopping and leaking stoppage structure and a water stopping and leaking stoppage method.The water stopping and leaking stoppage structure comprises a first semi-arc-shaped plate, a second semi-arc-shaped plate and a third semi-arc-shaped plate, and the inner concave face of the second semi-arc-shaped plate can be attached to the outer wall of a first lock catch steel pipe pile forming the cofferdam; the inner concave face of the third semi-arc-shaped plate can be attached to the outer wall of a second lock catch steel pipe pile forming the cofferdam, and the first lock catch steel pipe pile is adjacent to the second lock catch steel pipe pile. One side of the outer convex face of the first semi-arc-shaped plate is connected with one side of the outer convex face of the second semi-arc-shaped plate in a sealed mode, the other side of the outer convex face of the first semi-arc-shaped plate is connected with one side of the outer convex face of the third semi-arc-shaped plate in