1.Underground drainage materials 2.All-round flooding 3.Resistant corrosion ... are blocked outside,so as to achieve permeability,filtration,drainage once. Features: 1.Pore diameter is small,all- ... slump; 2.Airports,railways,roads,sports grounds,parks greening drainage; 3.Mine last dam,power plant ash dam, ... landfill plant drainage systerm; 4.The back of the tunnel wall ...