... .Widely used in the drainage of railway,highway ,tunnel HDPE double-wall corrugated pipe using HDPE as main material, and adds ... content, etc.1 Municipal engineering rainwater, sewage discharges;2 Industrial wastewater discharge, residential drainage works;3 Mine ventilation, drainage works;4 ... ,and the inner wall should be smooth , no burr. HDPE double-wall corrugated pipe