Interval Analysis Method And Application Study On Groundwater Hydraulic Budget Of Two-dimensional Confined Water Flow

Due to the complexity of groundwater system conditions,there are often uncertainties in the numerical simulation of groundwater head and groundwater budget.At present,stochastic and statistical approaches are generally used to quantify the uncertainties in numerical simulation,and made considerable progress.In these methods,a large number of sample data are required to determine the statistical characteristics(or PDFs)of the parameters,and that often difficult to obtain precisely in practical applications.This study takes the uncertainty of the groundwater budget in the numerical simulation of groundwater as the research object,and carries out the study of the interval uncertainty of the groundwater budget from the perspective of the interval uncertainty.The main content of the study is as follows:(1)By combining the existing interval parameter definition,perturbation method and firstorder interval parameter perturbation theory,this study gives the computation method of groundwater budget interval,and implements the method on the GFModel program.Aiming at a hypothetical example of unsteady flow in two-dimensional confined aquifer,this study compares the proposed method with the equal interval continuous sampling method(a method to obtain the theoretical interval of groundwater budget).The results show that the accuracy of the proposed method for the groundwater budget interval is high,and the computational efficiency is much higher than that of the equal interval continuous sampling method.(2)Based on the pumping test data and the hydrogeological conditions of the Sanbao hydrogeological proving ground,this study establishes a numerical simulation model,and divides into a deterministic model and an interval model according to different ways about parameters selection.Comparing the model simulations under the different scenarios,the results reflect that there are uncertainties in parameters of groundwater system.For the results of the interval model,the calculated interval can still better reflect the groundwater head changing of the actual pumping test and the changes of groundwater budget under different identification data.The accuracy of the interval model is high,and the feasibility is also.It shows that it is feasible to adopt the interval method of groundwater budget when the regional hydrogeological data is insufficient.(3)Finally,based on the interval model of the Sanbao hydrogeological proving ground,this study predicts the changes of groundwater budget under three different pumping conditions.