標題: Solution for Soil Vapor Extraction from a Pressure-Controlled Well
作者: Kuo, Ching-Lin
Fen, Chiu-Shia
Chen, Kai-Hsin
Yeh, Hund-Der
環境工程研究所
Institute of Environmental Engineering
關鍵字: Soil vapor extraction (SVE);Vertical well;Unsaturated soils;Mathematical model;Gas phase pressure
公開日期: 1-Jun-2017
摘要: This paper presents a new solution for a soil venting problem, in which a vertical, partially penetrating well is operated at a fixed pressure under covered, uncovered, or leaking ground surface conditions. The method of domain decomposition is applied to solve the problem of a mixed-type boundary condition imposed along a well screen, which in previous solutions was usually handled by discretization of the screen. The new solution is also capable of predicting the flow field beneath the well bottom, which is commonly neglected by other solutions. The authors found that the present solution may predict different pressure distributions from those given by a solution employing a constant flux rate at a well screen. The radius of influence for soil vapor extraction (SVE) operations is strongly affected by the radial permeability, the vertical permeability, and the ratio between the two. Vacuum pressure values were predicted with the proposed solution and compared against measurements at different observation wells and depths under venting tests at a former SVE-operated site. The measured vacuum pressure and gas flow velocity values around the wells were found to be substantially lower than the predicted values. Thus, the wellbore soils of the site were suspected to be positive skin zones. (C) 2017 American Society of Civil Engineers.
URI: http://dx.doi.org/10.1061/(ASCE)EE.1943-7870.0001213
http://hdl.handle.net/11536/145398
ISSN: 0733-9372
DOI: 10.1061/(ASCE)EE.1943-7870.0001213
期刊: JOURNAL OF ENVIRONMENTAL ENGINEERING
Volume: 143
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