1) Three-D Drainage Net 2) Net core: HDPE plastic It is ... filling site, road base and the inside of the tunnel.Three-D drainage net (also called 3D geotechnical drainage board, tunnel- ... filling site, road base and the inside of the tunnel. Three-D Drainage Net Technical Data Technical Data experimental technique units Type ... =1δv=20kPaISO12958l/m/s1.401.50a,b,c,d,eδv=100kPaISO12958l/m/s1.201.30a,b,c ...