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CLC number: TU43

On-line Access: 2016-07-05

Received: 2016-03-15

Revision Accepted: 2016-06-08

Crosschecked: 2016-06-16

Cited: 0

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Citations:  Bibtex RefMan EndNote GB/T7714


Liang-tong Zhan


Qing-wen Qiu


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Journal of Zhejiang University SCIENCE A 2016 Vol.17 No.7 P.541-552


Field measurement of gas permeability of compacted loess used as an earthen final cover for a municipal solid waste landfill

Author(s):  Liang-tong Zhan, Qing-wen Qiu, Wen-jie Xu, Yun-min Chen

Affiliation(s):  MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, Zhejiang University, Hangzhou 310058, China

Corresponding email(s):   zhanlt@zju.edu.cn

Key Words:  Compacted loess, Capillary barrier cover, Gas permeability, Volumetric water content, Landfill

Liang-tong Zhan, Qing-wen Qiu, Wen-jie Xu, Yun-min Chen. Field measurement of gas permeability of compacted loess used as an earthen final cover for a municipal solid waste landfill[J]. Journal of Zhejiang University Science A, 2016, 17(5): 541-552.

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publisher="Zhejiang University Press & Springer",

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%A Qing-wen Qiu
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T1 - Field measurement of gas permeability of compacted loess used as an earthen final cover for a municipal solid waste landfill
A1 - Liang-tong Zhan
A1 - Qing-wen Qiu
A1 - Wen-jie Xu
A1 - Yun-min Chen
J0 - Journal of Zhejiang University Science A
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The use of loess as an earthen final cover material is promising in northwest China which has an arid and semi-arid climate. A full-scale testing facility with an area 30 m long by 20 m wide was constructed at the Xi’an landfill of municipal solid wastes to investigate the performance of an inclined capillary barrier cover. The cover consisted of a compacted loess layer underlain by a gravel layer. The testing facility was well instrumented for a gas permeation test and recording of the soil conditions in terms of volumetric water content, pore gas pressure, and soil temperature. Tests were performed to measure the gas permeability of the compacted loess before and after the planting of vegetation on the cover. The field measurements demonstrate that the capillary break at the fine/coarse soil interface allows the upper compacted loess layer to retain more water, and conversely reduces its gas permeability, which is favorable for reducing landfill gas emissions. When the degree of saturation of the compacted loess was greater than 85%, the gas permeability decreased significantly with a further increment in volumetric water content. The growth of vegetation roots tended to fill the large pores in the upper loosely-compacted loess, resulting in a decrease in gas permeability of one order of magnitude. The influence of soil clods in the compacted loess on gas permeability can be one to two orders of magnitude due to an increase in pore size and a decrease in tortuosity.

This manuscript describes field measurement of gas permeability of a compacted loess that is proposed to be used as a final cover material for MSW landfill in Northwest China. The results provided by the authors are of interest to the researchers and practitioners from the field of landfill covers since the field experimental results of gas permeability of unsaturated loess have been rarely published in the literature. The experimental setup, instrumentation and procedure are provided in details. The authors do have some good descriptions and explanations of test results. However, a more in-depth interpretation of experimental data may help the readers to better understand the scale effect for field measurement as compared with laboratory measurement.


方法:1. 在西安固废填埋场建立压实黄土覆盖层试验基地(图2);2. 在试验基地的膜内核心测试区域布置通气试验系统,包括空气压缩机、通气管网、气压测试装置、含水率测试装置、温度传感器和静态箱(图3, 5~7);3. 在覆盖层表面裸露时和植草后分别进行通气试验测试压实黄土覆盖层的气相渗透系数。
结论:1. 当饱和度低于85%时,干密度为1.45 Mg/m3压实黄土的气相渗透系数随含水率增加而降低,但并不明显;但是当饱和度高于85%时,气相渗透系数随含水率增加而显著减小;2. 黄土层和碎石层之间的毛细阻滞作用使得上部黄土层储存更多水分,并显著降低其气相渗透系数,这有利 于降低填埋气的排放;3. 裸露条件下,当压实黄土的体积含水率从36%增加至46%时,其气相渗透系数从3.67×10-12 m2 降低至5.73×10-14 m2; 4. 植草后压实黄土的气相渗透系数比裸露条件下小近一个数量级,这主要是因为植被根系占据了压实黄土的大孔隙;5. 现场尺度的压实黄土气相渗透系数比室内试验的结果高1至2个数量级,这主要是因为现场所用黄土含有大的结团,结团会增加黄土的孔隙直径以及减小孔隙的曲折度。


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[1]Albright, W.H., Glendon, W.G., 2002. Alternative Cover Assessment Project (ACAP): Phase I Report. Desert Research Institute, USA.

[2]Albright, W.H., Benson, C.H., Gee, G.W., et al., 2004. Field water balance of landfill final covers. Journal of Environmental Quality, 33(6):2317-2332.

[3]Bolen, M.M., Roesler, A.C., Benson, C.H., et al., 2001. Alternative Cover Assessment Program: Phase II Report. Geo-Engineering Report.

[4]Benson, C.H., Bohnhoff, G.L., Ogorzalek, A.S., et al., 2005. Field data and model predictions for a monolithic alternative cover. Geo-Frontiers Congress 2005, Austin, Texas, USA, p.1-16.

[5]Hamamoto, S., Moldrup, P., Kawamoto, K., et al., 2011. Extreme compaction effects on gas transport parameters and estimated climate gas exchange for a landfill final cover soil. Journal of Geotechnical and Geoenvironmental Engineering, 137(7):653-662.

[6]Jucá, J.F.T., Maciel, F.J., 2006. Gas permeability of a compacted soil used in a landfill cover layer. Unsaturated Soils 2006, p.1535-1546.

[7]Khire, M.V., Benson, C.H., Bosscher, P.J., 1997. Water balance modeling of earthen final covers. Journal of Geotechnical and Geoenvironmental Engineering, 123(8):744-754.

[8]Kozlowski, T.T., 1999. Soil compaction and growth of woody plants. Scandinavian Journal of Forest Research, 14(6):596-619.

[9]Liu, F.Y., Zhang, Z., Zhou, D., 2010. Density-saturation-dependent air-water permeability function of unsaturated loess. Chinese Journal of Rock Mechanics and Engineering, 29(9):1907-1914 (in Chinese).

[10]Mcguire, P.E., Andraski, B.J., Archibald, R.E., 2009. Case study of a full-scale evapotranspiration cover. Journal of Geotechnical and Geoenvironmental Engineering, 135(3):316-332.

[11]Maciel, F.J., Jucá, J.F.T., 2000. Laboratory and field test for studying gas flow through MSW landfill cover soil. ASCE GeoDenver 2000, Advances in Unsaturated Geotechnics, p.569-585.

[12]Moldrup, P., Olesen, T., Komatsu, T., et al., 2001. Tortuosity, diffusivity, and permeability in the soil liquid and gaseous phases. Soil Science Society of America Journal, 65(3):613-623.

[13]Ng, C.W.W., Liu, J., Chen, R., 2015. Numerical investigation on gas emission from three landfill soil covers under dry weather conditions. Vadose Zone Journal, 14(8):1-10.

[14]Pierret, A., Moran, C.J., Pankhurst, C.E., 1999. Differentiation of soil properties related to the spatial association of wheat roots and soil macropores. Plant and Soil, 211(1):51-58.

[15]Stewart, J.B., Moran, C.J., Wood, J.T., 1999. Macropore sheath: quantification of plant root and soil macropore association. Plant and Soil, 211(1):59-67.

[16]Scanlon, B.R., Reedy, R.C., Keese, K.E., et al., 2005. Evaluation of evapotranspirative covers for waste containment in arid and semiarid regions in the southwestern USA. Vadose Zone Journal, 4(1):55-71.

[17]Wang, Y.C., Li, G.Z., Li, D.Y., 2003. The measurement of the gas viscosity factor. Physics and Engineering, 13(2):37-40 (in Chinese).

[18]Wickramarachchi, P., Kawamotoa, K., Hamamotoa, S., et al., 2011. Effects of dry bulk density and particle size fraction on gas transport parameters in variably saturated landfill cover soil. Waste Management, 31(12):2464-2472.

[19]Yao, Z.H., Chen, Z.H., Huang, X.F., et al., 2012. Experimental research on gas permeability of unsaturated Q3 loess. Chinese Journal of Rock Mechanics and Engineering, 31(6):1264-1273 (in Chinese).

[20]Zhan, L.T., Jia, G.W., Deng, L.H., et al., 2012. Performance of earthen final covers of landfills in humid areas. Chinese Journal of Geotechnical Engineering, 34(10):1812-1818 (in Chinese).

[21]Zhan, L.T., Yang, Y.B., Chen, R., et al., 2014. Influence of clod size and volumetric water content on gas permeability of a compacted loess. Canadian Geotechnical Journal, 51(12):1468-1474.

[22]Zhan, T.L., 2015. Moisture and gas flow properties of compacted loess final covers for MSW landfills in Northwest China. 6th Asian-Pacific Region Conference of Unsaturated Soil Mechanics, Guilin, China.

[23]Zhan, T.L., Ng, C.W.W., Fredlund, D.G., 2007. Field study of rainfall infiltration into a grassed unsaturated expansive soil slope. Canadian Geotechnical Journal, 44(4):392-408.

[24]Zhang, W.J., Qiu, Z.H., Zhou, C.R., et al., 2009. Evaluation of evapotranspiration covers of landfills in Yangtze River delta region. Chinese Journal of Geotechnical Engineering, 31(3):384-389 (in Chinese).

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