Please wait a minute...
ZJUS-A
Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering)  2016, Vol. 17 Issue (8): 667-676    DOI: 10.1631/jzus.A1500073
Articles     
One-dimensional coupled model for landfill gas and water transport in layered unsaturated soil cover systems
Chi Guan, Hai-jian Xie, Zhan-hong Qiu, Yun-min Chen, Pei-xiong Chen
School of Business Administration, Zhejiang Gongshang University, Hangzhou 310038, China; MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, Zhejiang University, Hangzhou 310058, China; Department of Civil Engineering, Taizhou University, Taizhou 317000, China; Second Institute of Oceanography, State Oceanic Administration, Hangzhou 310012, China
Download:     PDF (0 KB)     
Export: BibTeX | EndNote (RIS)      

Abstract  Cover systems are used to prevent water infiltration into a waste body. They also play an important role in controlling landfill gas transport from the waste body to the atmosphere. It is important to assess the flux of landfill gas at the surface of a cover system by considering the coupled effects of rainwater infiltration and gas transport in the cover soils. We have developed a 1D mathematical model for coupled transient gas and water transport in unsaturated cover soils. The coupled model was solved by the finite element method. Results obtained by the proposed model agreed well with experimental data. Based on the proposed solution, the influences of gas pressure, gas permeability, and the thickness of the cover soils on soil gas concentration profiles were investigated. The difference in soil gas concentration reached up to 31% as the thickness of cover increased from 1 to 2 m. Gas concentration at a depth of 0.2 m decreased by 6% as the amplitude of atmospheric gas pressure fluctuation increased from 20 to 100 Pa. The gas concentration increased by only 3% when gas permeability increased by a factor of 2 for a relatively long period of gas migration (e.g., 60 h) under the given conditions. Results suggest that both diffusion and advection should be considered when estimating gas transport in unsaturated cover soils. The numerical model can be used in the design of cover systems in relation to gas breakthrough time, breakthrough concentration, and flux.

Key words： Landfill gas      Cover systems      Unsaturated soils      Gas-water transport      Coupled model     
Received: 28 March 2015      Published: 05 August 2016
CLC:  TU43  
  X5  
Service
E-mail this article
Add to my bookshelf
Add to citation manager
E-mail Alert
RSS
Articles by authors
Chi Guan
Hai-jian Xie
Zhan-hong Qiu
Yun-min Chen
Pei-xiong Chen
Cite this article:

Chi Guan, Hai-jian Xie, Zhan-hong Qiu, Yun-min Chen, Pei-xiong Chen. One-dimensional coupled model for landfill gas and water transport in layered unsaturated soil cover systems. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2016, 17(8): 667-676.

URL:

http://www.zjujournals.com/xueshu/zjus-a/10.1631/jzus.A1500073     OR     http://www.zjujournals.com/xueshu/zjus-a/Y2016/V17/I8/667

[1] Xiao-chuan Liu, Wen-jie Xu, Liang-tong Zhan, Yun-min Chen. Laboratory and numerical study on an enhanced evaporation process in a loess soil column subjected to heating[J]. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2016, 17(7): 553-564.
[2] Guo-qing Cai, Cheng-gang Zhao, Jian Li, Yan Liu. A new triaxial apparatus for testing soil water retention curves of unsaturated soils under different temperatures[J]. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2014, 15(5): 364-373.
[3] HU Min-yun, CHEN Yun-min. ENGINEERING ASPECTS OF LANDFILLING MUNICIPAL SOLID WASTE[J]. Journal of Zhejiang University-SCIENCE A (Applied Physics & Engineering), 2001, 2(1): 34-40.