TY - JOUR
T1 - Thermo-hydro-mechanical behaviour of geothermal energy tunnel in different ground conditions
AU - Liu, Jinquan
AU - Zhou, Chao
N1 - Funding Information:
The authors would like to thank the National Science Foundation of China (NSFC) for providing financial support through the grant 52022004 .The authors also would like to thank the Research Grants Council (RGC) of the HKSAR for providing financial support through the grants 15200120 and 15205721.
Publisher Copyright:
© 2022 Elsevier Ltd
PY - 2022/11
Y1 - 2022/11
N2 - Energy tunnel is attracting increasing attention because it provides an innovative and efficient approach to harvest geothermal energy. Most of the previous studies focused on its thermal performance and little attention was paid to the thermo-hydro-mechanical behaviour during the operation of energy tunnel, such as lining deformation and ground movement. To address this problem, a numerical model that can simulate the coupled thermo-hydro-mechanical behaviour was developed in this study and verified by a field test. Then, comprehensive parametric studies were conducted to investigate the effects of key soil properties and states (i.e. permeability, thermal conductivity, coefficient of thermal expansion (CTE), elastic modulus, Poisson's ratio and tunnel burial depth) on the mechanical responses of energy tunnel and surrounding soils under cooling. It is found that: (1) CTE and elastic modulus among the above parameters are the most influential parameters for ground settlement and normal stress from soil to lining, respectively; (2) The thermally induced change in normal stress highly depends on the burial depth, with a percentage change of 24% for a shallow tunnel and 5% for a deep tunnel. Based on the guidelines of tunnel management, the thermally induced ground settlement is a more critical aspect than the lining deformation.
AB - Energy tunnel is attracting increasing attention because it provides an innovative and efficient approach to harvest geothermal energy. Most of the previous studies focused on its thermal performance and little attention was paid to the thermo-hydro-mechanical behaviour during the operation of energy tunnel, such as lining deformation and ground movement. To address this problem, a numerical model that can simulate the coupled thermo-hydro-mechanical behaviour was developed in this study and verified by a field test. Then, comprehensive parametric studies were conducted to investigate the effects of key soil properties and states (i.e. permeability, thermal conductivity, coefficient of thermal expansion (CTE), elastic modulus, Poisson's ratio and tunnel burial depth) on the mechanical responses of energy tunnel and surrounding soils under cooling. It is found that: (1) CTE and elastic modulus among the above parameters are the most influential parameters for ground settlement and normal stress from soil to lining, respectively; (2) The thermally induced change in normal stress highly depends on the burial depth, with a percentage change of 24% for a shallow tunnel and 5% for a deep tunnel. Based on the guidelines of tunnel management, the thermally induced ground settlement is a more critical aspect than the lining deformation.
KW - Energy tunnel
KW - Geothermal energy
KW - Numerical analysis
KW - Soil behaviour
KW - Thermo-hydro-mechanical response
UR - http://www.scopus.com/inward/record.url?scp=85135821114&partnerID=8YFLogxK
U2 - 10.1016/j.compgeo.2022.104954
DO - 10.1016/j.compgeo.2022.104954
M3 - Journal article
AN - SCOPUS:85135821114
SN - 0266-352X
VL - 151
JO - Computers and Geotechnics
JF - Computers and Geotechnics
M1 - 104954
ER -