Numerical Simulation Study on Loess Rainfall Infiltration Based on HYDRUS-1D Model
In order to study the infiltration law of loess water under rainfall conditions,an indoor loess soil column rainfall infiltration test was set up.The HYDRUS-1D model was used to simulate the infiltration law of rainfall,and the simulation accuracy was evaluated by using Root Mean Square Error(SRME)and Nash-Sutcliffe Efficiency Coefficient(SNE).The sensitivity of soil moisture characteristic parameters was ana-lyzed using the single factor disturbance method.The results show that the simulated soil moisture content values have a consistent trend with the measured experimental values,with very small errors.The SRME ranges from 0.011 to 0.017.Except for the SNE value corresponding to a soil column depth of 20 cm,which is less than 0.900,all other SNE values are greater than 0.900,indicating a good simulation effect.The ranking of the impact of soil moisture characteristic parameters on simulation results is θs>ks>n>α>θr.The disturbance of θs and α is nega-tively correlated with the simulation results,the disturbance of ks,n and θr is positively correlated with the simulation results.The infiltration pattern of shallow soil rainfall is less affected by parameter disturbances.As the depth of the soil column increases,the sensitivity of the pa-rameters gradually increases,and the impact of parameter changes on the simulation results gradually increases.