人为侵入体对城市绿地土壤水分入渗特征的影响

在快速城市化过程中,人为侵入体大量混入绿地,改变了土壤的三相组成及孔隙特征,但其对城市绿地土壤的入渗影响仍不清楚。基于一维垂直土柱入渗模拟,以典型人为侵入体砖块和混凝土碎块为例,研究其对城市绿地土壤水分入渗的影响特征。结果表明:(1)人为侵入体的混入均会抑制城市绿地土壤水分下渗,导致其稳定入渗速率降低,累积入渗量、湿润锋距离和土壤体积含水量减小,深层土壤水分变化滞后。同一配比下,以混凝土碎块对土壤水分入渗的抑制作用更为明显(P0.1);(2)随着人为侵入体配比从10%增加到20%,土壤稳定入渗率、累积入渗量、湿润锋距离和土壤体积含水量仍持续减小或略有增加,但差异均不显著(P0.1),其对土壤水分下渗的抑制作用渐趋减弱。(3)不同类型人为侵入体及配比下,城市绿地土壤水分的入渗量随时间变化更加符合Kostiakov模型。研究结果可为未来海绵城市的高效建设提供科学依据。

Influence of Anthropogenic Intrusions on the Soil Infiltration Characteristics in Urban Green Land

Amounts of anthropogenic intrusions are mixed into the urban green land soil with rapid urbanization,which lead to the alteration of solid-liquid-gas composition and porosity characteristics in soil system,but its effect on the infiltration process of soil is still unclear. The influence of typical anthropogenic intrusions (brick and concrete fragments) on soil infiltration characteristics in urban green land was studied according to the simulation experiments by one-dimensional vertical ponding infiltration in soil column. The results showed that: (1) Anthropogenic intrusions decreased the infiltration rate,cumulative infiltration amount,wetting front depth,and soil volumetric water content in urban green land,and more obvious inhibition on infiltration in green land soil was observed in concrete group than bricks group with the equal anthropogenic intrusions ratio (P<0.1). (2) With the anthropogenic intrusions ratios increasing from 10% to 20% in urban green land,the soil infiltration rate,cumulative infiltration amount,wetting front depth,and soil volumetric water content showed a continuous decreasing or slightly increasing trend,but all were not significant (P>0.1),which indicated that the inhibiting effect of anthropogenic intrusions on the soil infiltration was gradually weakened. (3) With different types and ratios of anthropogenic intrusions,Kostiakov model was mostly fitted to the relationship between cumulative infiltration amount and time. This research will provide scientific basis on the constructive establishment of sponge city in the future.