Open AccessStudy on Thermo-Mechanical Coupling Characteristics of Surrounding Rock of HLW Disposal Repository in Clay Rock
Author(s) -
Haian Liang,
Longpeng Zhang,
Jiongfeng Liang,
Chai Xin-jun
Publication year - 2020
Publication title -
iop conference series. earth and environmental science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.179
H-Index - 26
eISSN - 1755-1307
pISSN - 1755-1315
DOI - 10.1088/1755-1315/570/5/052047
Subject(s) - radioactive waste , coupling (piping) , geotechnical engineering , decay heat , spent nuclear fuel , stress (linguistics) , materials science , high level waste , drilling , thermal , geology , nuclear engineering , waste management , composite material , metallurgy , engineering , linguistics , philosophy , physics , meteorology
With the long-term decay, releasing a large amount of heat is one of the main characteristics of high-level radioactive waste. Safe operation of high-level radioactive waste repository must consider the effect of thermo-mechanical coupling on repository stability. In this paper, core drilling samples and in-situ stress tests were performed systematically on clay rock in Tamusu area. Thermal conductivity and triaxial tests were operated on samples near the depth of target layer of repository, to obtain the thermal and mechanical characteristics parameters. According to these parameters, a repository model was established in FLAC 3D to simulate excavation of repository and thermo-mechanical coupling of surrounding rock within 100 years after it closed. Results reveal that thermo-mechanical coupling effect has a significant impact on stability of repository. Thermal field reaches a steady state when high-level radioactive waste releases for 20 years, and the temperature in surrounding rock decrease as negative exponential with the distance from the gallery increases of. Due the temperature of the surrounding rock increases, thermal stress is generated, and the stress level in the near field of repository is growing as a whole, thus, strain increases. After heating without support for 100 years, there is the possibility of shear failure at the top and bottom of the chamber. It is necessary to reinforce the chamber lining to ensure the safe and stable operation of the repository.