Three-dimensional Drainage Mesh (also known as Three-dimensional Geotextile Drainage Board, Tunnel Drainage Board, and Drainage Board) is composed of double-sided adhesive plastic mesh with a geotextile fabric for permeability. It can replace traditional sand and gravel layers and is mainly used for drainage in landfill sites, road bases, and tunnel interiors.
Technical Parameters and Product Specifications of Composite Geotextile Drainage Mesh
In railway and highway infrastructure, the safety and service life of the projects are inextricably linked to their drainage systems, with geosynthetic materials being an essential component of these systems.
A three-dimensional composite drainage mesh is a new type of geosynthetic material. Its composition structure features a three-dimensional geotextile core, both sides bonded with needle-punched perforated nonwoven geotextile. The three-dimensional geotextile core includes a thick vertical rib, as well as one diagonal rib at the top and bottom. It can quickly drain subsoil water from roads and also has a pore maintenance system capable of blocking capillary water under high loads. Additionally, it serves as a separator and ground reinforcement.
The functional characteristics of the 3D composite drainage mesh:
1. Laid between the subgrade and subbase, it is designed to drain water between them, block capillary water, and effectively integrate with the edge drainage system. This structure automatically shortens the drainage path of the subgrade, significantly reducing drainage time, and allows for the use of a reduced quantity of selected subgrade materials (i.e., materials with more fine particles and lower permeability). It can also extend the service life of the road.
2. Laying a three-dimensional composite drainage grid at the base layer can prevent fine particles from the base layer from entering the subsoil, effectively acting as a barrier. Aggregate base will enter the upper part of the geotextile to a limited extent. Consequently, the composite geotextile drainage grid also has a potential role in restricting the lateral movement of the aggregate base, functioning similarly to the reinforcing effect of geogrids. Generally, the tensile strength and rigidity of the composite geotextile drainage grid are superior to many geogrids used for foundation reinforcement, enhancing the foundation's support capacity through this restrictive function.
3. After road aging and cracking, most of the rainwater enters the cross-section. In this case, directly laying a three-dimensional composite drainage mesh under the road surface instead of a permeable subgrade can be effective. The three-dimensional composite drainage mesh collects water before it enters the subgrade/subbase. Moreover, a film can be wrapped at the bottom of the three-dimensional composite drainage mesh to further prevent water from penetrating the subgrade. For rigid road systems, this structure allows for designing roads with a higher drainage coefficient Cd. Another advantage is that it may enable a more uniform hydration of concrete (research on the extent of this advantage is ongoing). This structure can extend the service life of both rigid and flexible road systems.
4. Under northern climatic conditions, laying a three-dimensional composite drainage net can help mitigate the effects of frost heave. If the depth of freezing is significant, the geotextile can be placed in a shallower position within the subgrade, acting as a capillary action barrier. Additionally, it is often necessary to replace the granular subgrade material with one that is less prone to frost heave, extending downwards to the depth of freezing. The frost-heave-prone backfill soil can be placed directly above the three-dimensional composite drainage net, up to the ground surface level of the foundation. In this case, the system can be connected to the drainage outlet, ensuring groundwater levels are at or below this depth. This can potentially limit the growth of ice crystals, allowing for unrestricted traffic loads during spring thaw in cold regions.
