Product technology of geosynthetic clay liner(GCL): Geosynthetic clay liner(GCL): is a new type of geosynthetic material. It adopts sodium-based bentonite particles through special technology and equipment to fix the bentonite particles between two layers of geotextile to make a bentonite mat. It has all the characteristics of geotechnical materials and has excellent waterproof (seepage) performance. The sodium-based bentonite mat produced by our company using needle punching method is a carpet-like material formed by needle punching of two layers of geotextile wrapped with sodium-based bentonite particles, as shown in the figure. Expressed with GCL-NP.