Analysis of the drainage effect of unsaturated soil subgrade with different drainage materials and technology

The groundwater in the subgrade always fluctuates under the influence of the atmosphere (rainfall, drainage, the fluctuation of river), especially in unsaturated soil. Thus, it is necessary to study the drainage effect of different drainage materials in unsaturated soil subgrade. This paper studies the drainage hydraulic calculation method of underground sewers, as well as its drainage effect in unsaturated soil subgrade. It shows that an underground sewer in the subgrade is necessary. The numerical calculation method of sewer drainage can be used to analyze the groundwater seepage in subgrade soils. The sewer can discharge the groundwater in sprinklers effectively. The other methods should be implemented to ensure the subgrade is in steady moisture, and the drainage ability is strong when the sewer is deep and it can be enhanced by increasing the number of sewers and reducing the space of the sewers.