TY - JOUR
T1 - Influence of biochar addition on gas permeability in unsaturated soil
AU - Garg, A.
AU - Bordoloi, S.
AU - Ni, J.
AU - Cai, W.
AU - Maddibiona, P. G.
AU - Mei, G.
AU - Poulsen, Tjalfe Gorm
AU - Lin, P.
N1 - Publisher Copyright:
© 2019 ICE Publishing: all rights reserved.
PY - 2019/3/1
Y1 - 2019/3/1
N2 - Biochar (BC) has been proposed as an alternative soil amendment in landfill cover. Its effects on soil hydraulic properties (e.g. soil water retention) have been explored to some extent, while its influence on landfill gas flow characteristics is not clear yet. The objective of this study is to investigate the water retention and gas permeability (kg) of BC-amended soil and its relationship with soil water content in unsaturated state. In total, three BC contents (0, 5 and 10%) were considered in clay-sand mixtures. Soil suction, water content and gas pressure were measured continuously using a new in-house developed apparatus. Test results show that the presence of BC increased soil water content and the increased amount was almost the same over a wide range of suction values (up to 3 MPa). kg increased linearly with soil suction in semi-log scale, regardless of the BC content. The addition of 5 and 10% of BC could decrease kg by up to 50 and 65%, respectively, compared with that of the bare soil. kg decreased with water content for both soil and BC-amended soils. Moreover, the decrease rate of kg with water content became smaller when the BC percentage was higher.
AB - Biochar (BC) has been proposed as an alternative soil amendment in landfill cover. Its effects on soil hydraulic properties (e.g. soil water retention) have been explored to some extent, while its influence on landfill gas flow characteristics is not clear yet. The objective of this study is to investigate the water retention and gas permeability (kg) of BC-amended soil and its relationship with soil water content in unsaturated state. In total, three BC contents (0, 5 and 10%) were considered in clay-sand mixtures. Soil suction, water content and gas pressure were measured continuously using a new in-house developed apparatus. Test results show that the presence of BC increased soil water content and the increased amount was almost the same over a wide range of suction values (up to 3 MPa). kg increased linearly with soil suction in semi-log scale, regardless of the BC content. The addition of 5 and 10% of BC could decrease kg by up to 50 and 65%, respectively, compared with that of the bare soil. kg decreased with water content for both soil and BC-amended soils. Moreover, the decrease rate of kg with water content became smaller when the BC percentage was higher.
KW - partial saturation
KW - permeability
KW - suction
UR - http://www.scopus.com/inward/record.url?scp=85065589839&partnerID=8YFLogxK
U2 - 10.1680/jgele.18.00190
DO - 10.1680/jgele.18.00190
M3 - Article
AN - SCOPUS:85065589839
SN - 2045-2543
VL - 9
SP - 66
EP - 71
JO - Geotechnique Letters
JF - Geotechnique Letters
IS - 1
ER -