长治市典型建成小区绿地土壤入渗特性研究

Study on Soil Infiltration Characteristics of Typical Existing Community Green Land in Changzhi

“渗”为海绵城市技术要素之首,而城市绿地是海绵城市建设的重要组成,开展城市绿地土壤入渗性能研究可为长治市构建城市“海绵体”提供科学支撑。以长治市典型建成小区绿地土壤为研究对象,采用野外单环入渗法测定了典型建成小区绿地表层土壤入渗过程,同时探讨了长治市城区典型建成小区绿地土壤物理性质对表层土壤入渗的影响,评价了3种常用入渗模型在该区域的适应性,并基于最优模型计算了不同平均雨强下典型建成小区绿地的溢流时间。结果表明:长治市典型建成小区绿地整体入渗能力较好,稳定入渗时间为50~100 min,稳定入渗速率在0.109~3.633 mm/min之间,其中老旧小区绿地稳渗最快;土壤理化性质空间异质普遍存在,入渗参数与容重、初始含水量成负相关,与田间持水量、饱和导水率成正相关;长治市建成小区绿地土壤入渗随时间变化过程更适用Horton模型;当建成小区绿地稳渗率为0.10 mm/min,且初始入渗率处于较高时,随平均雨强增大,溢流时间将逐渐缩短;若初始入渗率处于较低水平,其形成内涝风险将进一步增大,可针对绿地进行海绵化改造。

“Infiltration”is the first technical element of sponge city,and urban green land is an important component of sponge city construc⁃tion.Research on soil infiltration performance of urban green land can provide scientific support for the construction of urban“sponge body”in Changzhi.In this paper,the surface soil infiltration process of the typical built-up residential areas in Changzhi is measured by the field single ring infiltration method,and the influence of soil physical properties on surface soil infiltration is discussed.The adaptability of three commonly used infiltration models in this area is evaluated.Based on the optimal model,the overflow time of the green land under different average rainfall intensity is calculated.The results show that the overall infiltration capacity of green land in Changzhi is fairly good,with the stable infiltration time ranging from 50 to 100 min and the stable infiltration rate ranging from 0.109 to 3.633 mm/min,and the stable infiltra⁃tion of green land in old residential areas is the fastest.Spatial heterogeneity of soil physical and chemical properties are common.Infiltration parameters are negatively correlated with bulk density and initial water content,but positively correlated with field water capacity and saturated water conductivity. The Horton model is more suitable during the process of soil infiltration in the green land of Changzhi with changingover time. When the stable infiltration rate of the green land is 0.10 mm/min and the initial infiltration rate is at a high level, the overflowtime will gradually shorten with the increase of the average rainfall intensity. If the initial infiltration rate is at a low level, the risk of waterlog⁃ging will increase further. Therefore, the spongy reconstruction can be carried out for green space.