自然失水条件下土壤的入渗特性研究

STUDY ON INFILTRATION CHARACTERISTICS OF SOIL UNDER NATURAL DRYING PROCESS CONDITIONS

下凹绿地、雨水花园等生物滞留设施可参与雨水和地表径流的自然下渗与调节,是海绵城市建设的重要组成部分,雨水入渗对削减雨水外排具有重要作用。目前对土壤渗流的设计主要基于达西定律,但对非饱和土壤来说,达西定律并不广泛适用。对不同初始含水率土壤进行变水头渗透试验,得出其变水头渗透速度与时间的关系,并与达西定律计算结果进行对比,变水头渗透速度与时间的关系式可为海绵城市中土壤入渗的设计计算提供参考。

Bio-retention facilities,such as green space and rain garden participate in the natural infiltration and regulation of rainwater and surface runoff,and are important parts of the sponge city.The infiltration of rainwater plays an important role in the reduction of rainwater discharge quantity.At present,the design of soil seepage is mainly based on Darcy’s law,but Darcy’s law does not apply to the unsaturated soil.In the laboratory,the water head penetration test of different initial soil moisture content of the same soil was carried out.The change of initial soil moisture content was obtained by long-term natural water loss.A function relating water head penetration velocity and time was obtained and compared with the calculation result of Darcy’s law.The results may provide reference for calculation in future design of soil infiltration in sponge city.