Composite drainage board (also known as 3D composite drainage network, drainage grid) is a new type of drainage geotechnical material. It is made of high-density polyethylene (HDPE) and processed by a special extrusion process, with a three-layer special structure.

The drainage board is made of high-density polyethylene (HDPE) or polypropylene (PP), which is heated and pressed to form a lightweight sheet that can create a drainage channel with a certain three-dimensional spatial support rigidity and can also store water.