Study on sponge transformation of old residential area based on permeable filter element technology

The existing sponge reconstruction measures in old residential areas each have their own advantages and disadvantages in application. Building upon this, a seepage well technology using a pervious concrete filter core is proposed. Preliminary calculations for this technology were conducted through numerical simulation and compared with common unrestricted site conditions to examine its applicability. Rainfall simulations were performed for infiltration devices with spacings of 2, 3, and 5 m, as well as for unrestricted sites, and the resulting cloud images of total water head, pore water pressure, and saturation were compared and analysed. In addition, further comparative analysis was carried out using numerical simulations in the MIDAS software. The results indicate that after rainfall, the overall total water head in the area equipped with filter elements shows a general declining trend. Saturation across the site gradually increased with prolonged rainfall duration. The arrangement of filter elements can effectively enhance soil seepage velocity, mitigate surface water accumulation, and consequently reduce soil saturation. The deployment of permeable filter elements can thus effectively alleviate waterlogging and improve the environmental conditions.