摘要
高温季节土壤表层温度非常高,土壤内部含水率较低,突发性降雨对于土壤温度动态变化和水热交换运移影响极大。为了揭示降雨非饱和入渗对土壤热量运移变化的影响,该研究建立了反映降雨入渗过程的土壤热量运移数学模型,编制了有限元数值计算程序,针对南京雨花台区典型土壤,开展了降雨非饱和入渗对土壤热量运移影响的数值计算与分析研究。结果表明:不考虑降雨入渗情况下,土壤温度变化与热量运移主要是表层土壤与环境之间的热交换作用引起,热量运移影响深度约0.2 m;降雨强度45 mm/h作用下,随降雨历时增加,雨水全部自由入渗到土壤内部,土壤内部基质吸力呈线性递减趋势,湿润锋面逐渐下移,土壤体积含水率快速增加;湿润锋过后的土壤体积含水率逐渐接近于饱和体积含水率,土壤入渗能力逐渐下降,直至趋于饱和入渗率;在降雨非饱和入渗影响下,入渗到土壤孔隙中的低温雨水与土壤颗粒发生热量交换,进而改变了原有土壤温度场分布,并随着降雨入渗深度的持续增加,降雨入渗过程对土壤热量运移的影响呈现逐渐减弱趋势。经过现场实测数据与模拟计算结果验证,随着降雨历时增加,土壤体积含水率实测值和数值计算值相对误差保持在±3.99%以内,均方根误差RMSE为0.01 cm^3/cm^3;土壤温度实测值和数值计算值的相关误差保持在±2.72%以内,均方根误差RMSE为0.55℃,模拟计算结果和现场实测数据均吻合较好,表明该模型对描述降雨非饱和入渗过程土壤热量运移规律的适应性较强,数值计算程序合理。研究成果可为农业水利工程与水土保持、土壤水文水资源的分布与利用、城市水资源控制与生态环境保护等领域提供重要参考。
In the high temperature season,the surface temperature of the soil is very high,and the internal moisture content of soil is low.A sudden rainfall has a great influence on the dynamic change of soil temperature,and as well as the water-heat exchange and migration.Temperature change of soil surface and water movement can be interacted with each other during this time.It is also very important to reveal the influence mechanism of water movement caused by rainfall unsaturated infiltration,on temperature change of soil and the law of heat transfer.However,there are only a few research achievements on the hydrothermal interaction of soil in the process of rainfall unsaturated infiltration.In this study,a mathematical model of soil heat transfer in the process of rainfall infiltration was established,and the corresponding finite element numerical calculation program was compiled,in order to reveal the soil moisture movement in unsaturated rainfall infiltration process of high temperature,and the influence mechanism of soil heat transfer.Taking the typical silt soil layers in Nanjing as research objects,a numerical analysis was carried out for the unsaturated rainfall infiltration exerting to the function of soil heat transfer.The results showed that without considering rainfall infiltration,the soil temperature change and heat transfer were mainly caused by the heat exchange between the surface soil and the environment,where the depth of heat transfer was about 0.2 m.Under the action of rainfall intensity of 45 mm/h,the soil matric suction and volume moisture content in the silt layer changed gradually with the duration of rainfall,due to the unsaturated infiltration process of rainfall.When the soil moisture front moves down and reached different depths,the volume moisture content increased rapidly,and the soil volume moisture content after the moist front gradually approached the saturated volume moisture content and the soil infiltration capacity gradually decreased until reaching the saturation infiltration rate.In
作者
张超
姜景山
王如宾
金华
Zhang Chao;Jiang Jingshan;Wang Rubin;Jin Hua(Department of Municipal Engineering,School of Architecture Engineering,Nanjing Institute of Technology,Nanjing 211167,China;Institute of Geotechnical Engineering,School of Architecture Engineering,Nanjing Institute of Technology,Nanjing 211167,China;Institute of Geotechnical Engineering,Hohai University,Nanjing 210098,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2020年第18期118-126,共9页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家重点研发计划(2017YFC1501104)
国家自然科学基金项目(51679069,51409082)
南京工程学院引进人才科研启动基金(YKJ201729)。
关键词
土壤
温度
热量运移
降雨非饱和入渗
水分运动
数值计算
soils
temperature
heat transfer
rainfall unsaturated infiltration
water movement
numerical calculation
