海绵城市建设中土水特征曲线对产流的影响

Effect of Soil-water Characteristic Curve on Runoff in Sponge City Construction

土壤土水特征曲线是海绵城市建设中源头控制阶段的重要参数,是降雨入渗及产流研究的理论基础。针对海绵城市试点庄河市建设的实际情况,对当地3类土壤进行土水特征曲线测定,拟合计算得到土壤基质吸力、非饱和导水系数方程,结合Green-Ampt改进模型计算各类土壤所处区域在不同降雨强度下的雨水入渗及产流情况。结果表明:土壤入渗能力总体呈现为人工回填土>裸露坡地土>耕种土,人工回填土的入渗率是其他土壤的1.1~4.4倍。在降雨强度为大暴雨等级时,人工回填土的延迟产流时间是其他土壤的1.9~5.8倍;在特大暴雨时,3类土壤短时间内均会产生超渗产流,此时在延缓洪峰时间、控制洪峰流量上没有明显作用。

The soil-water characteristic curve of soil is an important parameter in the source control stage of sponge city construction,and it is the theoretical basis for the study of rainfall infiltration and runoff.According to the actual situation of sponge city construction of Zhuanghe(a pilot sponge city),the soilwater characteristic curves of three local soils were determined,and the soil matrix suction and unsaturated permeability equation were obtained by fitting calculation.Then,the rainfall infiltration and runoff under different rainfall intensities were calculated by using the Green-Ampt improved model.The order of soil infiltration capacity was as follows:manual backfill soil>bare slope soil>tillage soil,and the infiltration rate of the manual backfill soil was about 1.1-4.4 times that of the other soils.During a heavy rain,the delayed runoff time of the manual backfill soil was 1.9-5.8 times that of the other soils.In the case of an extremely heavy rain,all the three kinds of soil would produce excess runoff in a short time,which had no obvious effect on delaying flood peak time and controlling flood peak flow.