... areases of the railway,highway,sport venue,dyke,water project construction,tunnel,sea beach,inning and so on. PP Needle ... layer of the dykes, river canal, seacoast, concrete slope, retaining walls. At the same time of preventing the clay granule ... , railway, soil-stone dam, breakwater, airport, backfill soil of retaining wall, slope protection, etc in which distributes the earth stress, prevents ...