Composite Drainage Net

Composite drainage net is a new type of drainage geotechnical material. Made from high-density polyethylene (HDPE) as the raw material, it is processed through a special extrusion molding technique and features a unique three-layer structure. The central ribs are highly rigid and arranged longitudinally to form drainage channels, while the upper and lower cross-arranged ribs provide support to prevent geotextile from embedding into the drainage channels, maintaining high drainage performance even under heavy loads. When bonded on both sides with permeable geotextile, it offers comprehensive functions of "filtration—drainage—breathability—protection," making it an ideal drainage material currently available.

Product Applications:

Mainly used in drainage projects for railways, highways, tunnels, municipal engineering, reservoirs, slope protection, etc., with significant effects.

Product Features:

1. High drainage capacity (equivalent to one meter thick gravel drainage).

2. High tensile strength.

3. Reduces the likelihood of geotextile embedding into the net core, ensuring long-term stable drainage.

4. Capable of withstanding high-pressure loads over the long term (can bear compressive loads of approximately 3000 kPa).

5. Corrosion-resistant, acid and alkali resistant, with a long service life.

6. Easy construction, shortens project duration, and reduces costs.

Functions: 1. Laid between the foundation and subbase, it is used to drain accumulated water between the foundation and subbase, block capillary water, and effectively integrate into the edge drainage system. This structure automatically shortens the drainage path of the foundation, significantly reducing drainage time, and allows for the use of fewer selected foundation materials (i.e., materials with more fines and lower permeability). It can extend the service life of roads.

2. Installing a drainage net in the subbase can prevent fine subbase materials from entering the foundation layer (i.e., acting as a separator). The aggregate base will partially enter the upper section of the geonet to a limited extent. In this way, the composite geotechnical drainage net also has a potential role in restricting the lateral movement of the aggregate base, functioning similarly to the reinforcement effect of geogrids. The tensile strength and rigidity of the composite geotechnical drainage net are comparable to many geogrids used for foundation reinforcement, and this restraining effect will enhance the foundation's load-bearing capacity. 

3. After road aging and crack formation, most rainwater will enter the cross-section. In such cases, the drainage net is laid directly under the pavement to replace the drainable foundation. The drainage net can collect moisture before it enters the foundation/subbase. Additionally, a membrane can be wrapped around the bottom of the drainage net to further prevent moisture from entering the foundation. For rigid road systems, this structure allows for the design of roads with a higher drainage coefficient Cd. Another advantage of this structure is that it may promote more uniform hydration of concrete (research on the extent of this benefit is ongoing). Whether for rigid or flexible road systems, this structure can extend the service life of the road.

4. In northern climates, installing a drainage net can help mitigate the effects of frost heave. If the frost depth is significant, the geonet can be placed at a shallower depth within the subbase to act as a capillary block. Additionally, it is often necessary to replace the subbase with non-frost-susceptible granular material extending down to the frost depth. Frost-susceptible backfill can be placed directly on top of the drainage net up to the foundation grade. In this scenario, the system can be connected to a drainage outlet to keep the groundwater level at or below this depth. This can potentially limit the development of ice lenses, allowing for unrestricted traffic loads during spring thaw in cold regions without the need for load restrictions.