As Mongol raids continued periodically over the years, the Ming devoted considerable resources to repair and reinforce the walls.
由于蒙古族的多年持续入侵，明朝投入大量财力、物力对长城进行修筑及加固。
2
The plan to repair and reinforce the underground inclined channel of a uranium tailings dam and the application of PCC material in the project are introduced in detail.