In transportation infrastructure such as railways and highways, the safety and service life of the project are closely related to its own drainage system, and geosynthetic materials are an important component of the drainage system.

Two dimensional composite drainage network

Three dimensional composite drainage network is a new type of geosynthetic material. The composition structure is a three-dimensional geotextile core, with needle punched non-woven geotextiles glued on both sides. The three-dimensional geonet core consists of a thick vertical rib, as well as one diagonal rib at the top and one at the bottom. It can quickly discharge groundwater from roads and has a pore maintenance system that can block capillary water under high loads.

Three dimensional composite drainage network

Three dimensional composite drainage network

At the same time, it can also serve as an isolation and foundation reinforcement function. A new type of geosynthetic material.

The three-dimensional composite drainage network is made of a unique three-dimensional geonet double-sided bonded geotextile. Combining geotextile (filter function) and geonet (drainage and protection function), providing a complete "filter drainage protection" effect.

The unique three-dimensional structure of the core of the three-dimensional composite drainage network can withstand high compressive loads and maintain a considerable thickness throughout the entire use process, providing excellent hydraulic conductivity.

3 Characteristics

Characteristics of 3D composite drainage network:

1. When the load is 720kPa and the gradient is 2%, the permeability is 2500m/d and the flow rate is 13pm/m.

2. After withstanding a load of 1200kPa for 10000 hours, the creep test retained over 60% of the thickness of the three-dimensional drainage network

3. The carbon black content of the three rib drainage network core is not less than 2%, the density is 0.94g/cm3, the tensile strength is not less than 36.5kN/m, the melt index is 1.0 g/10min, and the thickness is 7.6mm.

4. The non-woven geotextile has an apparent pore size of 0.18mm, a permeability of 0.26 Sec-1, a permeability of 0.2cm/sec, a puncture strength of 580N, a trapezoidal tear strength of 356 N, a grip tensile strength of 900 N, a grip tensile strength of 50%, and a burst strength of 2750kPa.

4 Functions

The functional characteristics of three-dimensional composite drainage network:

1. Laying between the foundation and base, used to drain accumulated water between the foundation and base, block capillary water, and effectively integrate into the edge drainage system. This structure automatically shortens the drainage path of the foundation, greatly reduces the drainage time, and can also reduce the amount of selected foundation materials used (i.e., materials with more fine materials and lower permeability can be used). It can extend the service life of roads.

2. Laying a three-dimensional composite drainage network on the subgrade layer can prevent fine materials from entering the subgrade layer (i.e., serve as a barrier). The aggregate base layer will enter the upper part of the geonet to a limited extent. In this way, the composite geotextile drainage network also has a potential function of restricting the lateral movement of the aggregate base layer, similar to the reinforcement effect of geogrids. Generally speaking, the tensile strength and rigidity of composite geotextile drainage networks are superior to many geogrids used for foundation reinforcement, and this limiting effect will improve the support capacity of the foundation.

3. After the road ages and cracks form, most of the rainwater will enter the cross-section. In this case, the three-dimensional composite drainage network is directly laid under the road surface instead of a drainage foundation. The three-dimensional composite drainage network can collect water before it enters the foundation/subgrade layer. Moreover, a layer of film can be wrapped around the bottom of the three-dimensional composite drainage network 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 enable more uniform hydration of concrete (research on the extent of this advantage is currently underway). This structure can extend the service life of both rigid and flexible road systems.

4. Under northern climate conditions, laying a three-dimensional composite drainage network can help alleviate the impact of frost heave. If the freezing depth is very deep, the geonet can be laid in a shallower position in the foundation to block capillary action. In addition, it is often necessary to replace it with a granular base layer that is not prone to frost heave and extends downwards to the freezing depth. The backfill soil that is prone to frost heave can be directly filled on top of the three-dimensional composite drainage network until the ground surface line is reached. In this case, 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 crystals, without restricting traffic loads during spring ice melting in cold regions.

Three dimensional composite drainage network is a new type of geotechnical material for drainage. Made from high-density polyethylene (HDPE) as raw material and processed through a special extrusion molding process, it has a three-layer special structure. The middle reinforcement has high rigidity and is arranged longitudinally to form a drainage channel. The cross arranged reinforcement forms a support to prevent the geotextile from being embedded in the drainage channel, and can maintain high drainage performance even under high loads. Double sided adhesive permeable geotextile composite use, with comprehensive performance of "filtration drainage breathability protection", is currently the most ideal drainage material.

5 Product Applications

Mainly used in drainage projects such as railways, highways, tunnels, municipal engineering, reservoirs, and slope protection, the effect is significant.

6 Product Features

1. Strong drainage (equivalent to one meter thick gravel drainage).

2. High tensile strength.

3. Reduce the probability of geotextile embedding into the mesh core and maintain long-term stable drainage.

4. Long term withstand of high-pressure loads (able to withstand compression loads of approximately 3000 Ka).

5. Corrosion resistance, acid and alkali resistance, and long service life.

6. Convenient construction, shortened construction period, and reduced costs.

Joint and overlap of 7 three-dimensional composite drainage networks

1. Adjust the direction of geosynthetic materials so that the length direction of the material roll is perpendicular to the road.

2. The composite geotextile drainage network must be terminated, and the geotextile on adjacent geotextile cores should be overlapped along the material roll.

3. Connect the geotextile cores of adjacent geotextile rolls with white or yellow plastic buckles or polymer straps to connect the material rolls. Connect with straps every 3 feet along the length of the material roll.

4. The direction of the overlapped geotextile should be consistent with the direction of the filling material stacking. If the geotextile material is laid between the foundation/base layer and the sub base layer, continuous wedge welding, flat head welding or stitching should be carried out to fix the overlapping geotextile upper layer. If suturing, it is recommended to use flat head sewing method or general sewing method to achieve the minimum requirement for stitch length.

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