Geotextile has good water conductivity, it can form a drainage channel inside the soil, and discharge the unnecessary liquid and gas from the soil.Geotextile used for drainage generally includes two methods of vertical penetration and horizontal drainage. When the impermeable asphalt bonding layer is laid on the base layer, the drainage channel of the geotextile is mainly horizontal drainage. When there is no asphalt bonding layer on the roadbed, the drainage path is mostly vertical, but the horizontal drainage is also carried out at the same time.
In the initial stage of the roadbed without asphalt bonding layer, due to gravity and the permeability of the base water, the vertical penetration is more, but as the water absorption becomes saturated and the water permeability decreases, the horizontal drainage will be more. This is why some roads are fine with light rain when the lateral drainage is not good, but they become muddy when there is a lot of rain.
2. Horizontal drainage:
The pavement where waterproof and drainage measures are taken when laying the base course has more horizontal drainage. In addition to the impervious asphalt layer above, the waterproof measures should also take necessary drainage measures, such as drainage canals on both sides, etc. When laying geotextiles as a basic drainage measure, the lateral drainage capacity should be strengthened to drain the base water as soon as possible. Ensure the stability of the grassroots and improve the performance of road traffic.