Function and Characteristics of the Wantong Composite Drainage Network

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. The creep test retains more than 60% of the thickness after withstanding a load of 1200kPa for 10000 hours.

3D drainage network

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

4. The nonwoven geotextile has an apparent pore diameter of 0.18mm, a water 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 elongation strength of 50%, and a burst strength of 2750kPa.

Function characteristics of three-dimensional composite drainage network:

1. It is laid between the foundation and subbase to drain the accumulated water between the foundation and subbase, block the capillary water and effectively integrate it into the edge drainage system. This structure automatically shortens the drainage path of the foundation, greatly shortens the drainage time, and reduces the use of selected foundation materials (i.e., materials with more fine materials and lower permeability). It can prolong the service life of roads.

2. Laying a three-dimensional composite drainage network on the subbase can prevent the fine subbase materials from entering the subbase (that is, it plays an isolation role). The aggregate base course will enter the upper part of the geotextile to a limited extent. In this way, the composite geotextile drainage network also has a potential role in limiting the lateral movement of the aggregate base. In this way, its role is similar to that of the geogrid reinforcement. In general, the tensile strength and rigidity of composite geotextile drainage network are superior to many geogrids used for foundation reinforcement, and this limiting effect will improve the supporting capacity of the foundation.

3. After the road is aged and cracks are formed, most of the rainwater will enter the section. In this case, the three-dimensional composite drainage network is directly laid under the pavement to replace the drainage foundation. The three-dimensional composite drainage network can collect water before it enters the foundation/subbase. In addition, a film can be wrapped at the bottom of the three-dimensional composite drainage network to further prevent moisture from entering the foundation. For the rigid road system, this structure allows the road to be designed with a higher drainage coefficient Cd. Another advantage of this structure is that it is possible to hydrate the concrete more evenly (research on the extent of this advantage is ongoing). Whether for rigid roads or flexible road systems, this structure can extend the service life of roads.

4. In the northern climate, the laying of three-dimensional composite drainage network can help reduce the impact of frost heave. If the freezing depth is very deep, the geotextile can be laid at a shallow position in the subbase as capillary blockage. In addition, it is often necessary to replace the granular subbase that is not easy to frost heave, extending down to the freezing depth. The backfill soil easy to frost heave can be directly filled on the three-dimensional composite drainage network until the ground surface line. In this case, the system can be connected to the drainage outlet so that the groundwater level is at or below this depth. In this way, the development of ice crystals can be potentially limited. When ice melts in cold regions in spring, there is no need to limit the traffic load.