The composite drainage net has excellent drainage performance, capable of effectively removing surface seepage and stabilizing the slope of the landfill closure. The gas drainage layer of the landfill closure system may have insufficient exhaust capacity or lack a flat gas drainage layer, leading to excessive gas pressure applied to the impermeable layer, which could potentially damage the closure system. The gas drainage layer of the closure system can utilize the high-performance composite drainage net. The high-performance composite drainage net or a three-dimensional composite drainage net combined with sand and gravel can be used to form the gas drainage layer of the landfill closure system. Utilizing the three-dimensional composite drainage net as both the surface water drainage and gas drainage layer in the landfill closure system is suitable for steep slopes, as its high drainage performance can effectively remove seepage and gas, ensuring slope stability.

The purpose of the final landfill cover closure system is to limit precipitation infiltration into the landfill and minimize the production of leachate that could contaminate water sources. In the closure system, the surface water drainage layer's function is to discharge water that infiltrates the cover soil, preventing accumulation on the impermeable layer. Water accumulation on the closure impermeable layer can generate pore water stress, potentially causing the vegetation cover soil to slide and damaging the closure slope. Traditionally, sand and gravel are used as the surface water drainage layer for closures, which is challenging to place on steep slopes. However, the use of three-dimensional composite drainage grids can be suitable for steep closure slopes and also increase the landfill volume.

The lifespan of the three-dimensional composite drainage mesh is primarily determined by whether the plastic film loses its impermeable water-sealing function. According to Soviet standards, polyethylene film with a thickness of 0.2m and stabilizers used in hydraulic engineering can last 40 to 50 years under clean water conditions and 30 to 40 years under wastewater conditions. Therefore, the lifespan of the three-dimensional composite drainage mesh is sufficient to meet the requirements for the dam's impermeability.

The渗漏 prevention effectiveness of the three-dimensional composite drainage grid depends on the integrity of the plastic film during construction and operation. To prevent trampling by humans and animals, as well as damage from plants and animals, and to reduce the effects of light and heat, since they are high molecular fiber polymers, direct sunlight exposure should be avoided. Therefore, a protective layer should be laid over the three-dimensional composite drainage grid.