南京大学学报（自然科学版）2011，Vol.47Issue(3)：252-264,13.
运用水力层析法刻画潜水含水层的非均质性
Hydraulic tomography to characterize heterogeneity of unconfined aquifers
摘要
Abstract
Analytical models are the most widely used tools for analyzing pumping tests in unconfined aquifers. Ground water flow induced by a pumping test in an unconfined aquifer is highly nonlinear near the water table. These analytical models are inadequate to describe the nonlinear flow due to their simplified representations of the drainage process and drawdowns at the water table. Moreover, these models assume aquifer homogeneity while real aquifers are inherently heterogeneous. Recently emerged hydraulic tomography ( HT) is a cost-effective method for mapping spatial distribution of aquifer hydraulic properties. HT takes advantage of the power of numerical models and fuses information from multiple cross-hole tests conducted at different locations to image aquifer properties in greater details. In this study, we extend the HT concept to unconfined aquifers. To accurately describe the groundwater flow due to a HT survey in an unconfined aquifer, a fully three dimensional variably saturated flow model based on mixed form of the Richards equation is used. Pressure responses in both saturated and unsaturated zones are used to estimate spatial variations of hydraulic conductivity, specific storage, and a soil water constitutive model parameter through a successive linear estimator. A sensitivity analysis is performed to investigate the relation between pressures and different parameters. The HT method for unconfined aquifers is then tested in a synthetic three dimensional field scale aquifer. The test shows that the proposed HT method can effectively map spatial variations of hydraulic parameters in an unconfined aquifer. While characterizing hydraulic conductivity in both saturated and unsaturated regimes is possible, characterization of specific storage is limited in the saturated flow regime and characterization of the soil water constitutive model parameter is limited in the unsaturated flow regime. The other limitations of HT for unconfined aquifers and potential improvements are also discussed.关键词
水力层析法/潜水含水层/非均质性/含水层刻画/连续线性估计法Key words
hydraulic tomography/ unconfined aquifer/ heterogeneity/ aquifer characterization/successive linear estimator分类
天文与地球科学引用本文复制引用
朱珺峰,叶天齐,毛德强..运用水力层析法刻画潜水含水层的非均质性[J].南京大学学报（自然科学版）,2011,47(3):252-264,13.基金项目
Strategic Environmental Research and Development Program (SERDP) （SERDP）
