Improvement of comprehensive performance of compound green soil in sponge city

Abstract

Large-scale constructions of urbanization increase the impervious areas of city, leading to the urban hydrological effects such as urban waterlogging and rainwater runoff pollution. To this end, China proposed to adopt the measure to build sponge cities. However, the existing green soil cannot meet the comprehensive needs of sponge city. In order to quickly evaluate the comprehensive performance of the soil in sponge city, a comprehensive evaluation criterion was designed, which is related to the characteristics of greening soil permeability, porosity, pH, salinity and fertility. Based on the criterion, a new type of composite green soil was obtained with the silt soil: medium sand: sawdust ratio of 72.5%: 20%: 7.5%. Finally, compared with the existing soil, the new green soil not only meets the comprehensive performance requirements of the green soil's fertility, pH, permeability and other factors, but also has higher permeability and water retention. It was proved that the new green soil has apparent advantages in the control of rainwater.