Analysis of flow due to pumping in a sloping fault zone unconfined aquifer considering nonlinear free surface equation
| Autor: | Yang, Kai-Ting, 楊凱婷 |
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| Rok vydání: | 2016 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 104 The nonlinear free-surface equation (NFSE) has been simplified to a linear one, called linear free-surface equation, LFSE, based on two assumptions that (1) squared hydraulic gradients are ignorable and (2) water table movement is much smaller than the initial aquifer thickness. This study relaxes these two assumptions by applying the superposition principle to deal with the NFSE for the problem of flow toward a well in a sloping fault-zone unconfined aquifer. We consider two-dimensional flow in rectangular aquifer domain with one side, moving boundary satisfying the NFSE, at the outcrop and the other three sides, no-flow strata, under the ground. Image wells surrounds the aquifer boundary. The aquifer drawdown subject to the NFSE equals the sum of the Theis [1935] solution for the extraction well and a simple series for the image wells. The volumetric rates of the image wells are the solution of a system of equations arisen from substituting the present solution into the NFSE. Research results indicate that the validity of the LFSE depends on the magnitude of dimensionless parameter q=Q/(4πTw_1 sinθ) where Q is the volumetric rate of the extraction well, T is the aquifer transmissivity, w_1 is a distance between the extraction well and outcrop in the sloping direction, and θ is the inclination of the aquifer. When q 0.01, the LFSE causes significant error in predicting water table location compared with that based on the NFSE. Keywords: free-surface equation, squared hydraulic gradient, image well, superposition principle, sloping fault-zone aquifer |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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