Abstract: As a rainwater runoff control technology, bioretention facilities play an important role in restoring regional hydrological cycle. However, due to the differences in underground soil quality in different regions, the operational effectiveness of bioretention facilities will be affected differently. The water transport process of bioretention facilities under a single rainfall event was studied by the VADOSE/W model. The influence characteristics of four in-situ soil types such as silt loam, loam, sandy clay loam and sandy loam on the surface ponding, underdrain outflow, exfiltration and runoff regulation effects of bioretention facilities were studied. The research results show that when bioretention facilities are not equipped with an underdrain and the permeability coefficient of in-situ soil is relatively small, it is easy to prolong the surface ponding time and increase the overflow water amount. The underdrain outflow in bioretention facilities is significantly affected by the in-situ soil. With the decrease of the permeability coefficient of in-soil, the outflow peak value of underdrain increases and the outflow duration is prolonged. The exfiltration of bioretention facilities is dominated by bottom seepage, the amount of exfiltration volume per unit area can reach 2.78~7.82 times that of lateral seepage, and as the in-situ soil permeability coefficient increases, the exfiltration volume at the bottom correspondingly increases. With the increase of in-situ soil permeability coefficient, the reduction rate of runoff, the reduction rate of runoff peak and the delay time of runoff production of bioretention facilities are all relatively increased.

Key words: highway engineering; environmental engineering; road bioretention; in-situ soil; hydrological effect

摘要： 生物滞留设施作为一种雨水径流控制技术对恢复区的水文循环具有重要作用，但由于不同地区地下土质的差异性，会对生物滞留设施的运行效果产生不同影响。通过VADOSE/W模型对生物滞留设施在单一降雨事件下的水分运移过程进行了研究；分析了淤泥质壤土、壤土、砂质黏壤土、砂壤土等4种原位土类型对生物滞留设施的表层积水、穿孔管产流、水分外渗及径流调控效应的影响特性。研究结果表明：当生物滞留设施未设置穿孔排水管且原位土渗透系数相对较小时，易导致表面积水时间延长、溢流水量增大；生物滞留设施的穿孔管产流受原位土影响显著，随着原位土渗透系数减小，穿孔管产流峰值增大，产流历时延长；生物滞留设施的外渗以底部渗透为主，单位面积的外渗水量可达到侧向的2.78~7.82倍，且随着原位土渗透系数增加，底部外渗水量相应增大；随着原位土渗透系数增大，设施的径流量消减率、径流峰值消减率及产流延时均相对提高。

关键词: 道路工程；环境工程；道路生物滞留；原位土；水文效应