Rock and Soil Mechanics ›› 2020, Vol. 41 ›› Issue (3): 1056-1064.doi: 10.16285/j.rsm.2019.5450

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Thermo-hydro-mechanical coupling numerical simulation method for high-level waste geological repository considering excavation damage

HOU Hui-ming1, 2, HU Da-wei1, 2, ZHOU Hui1, 2, LU Jing-jing1, 2, LÜ Tao3, ZHANG Fan4   

  1. 1. State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan, Hubei 430071, China 2. University of Chinese Academy of Sciences, Beijing 100049, China 3. China Nuclear Power Engineering Co., Ltd., Beijing 100840, China 4. School of Civil Engineering, Architecture and Environment, Hubei University of Technology, Wuhan, Hubei 430064, China
  • Online:2020-03-27 Published:2020-09-27
  • Contact: HU Da-wei, male, born in 1981, PhD, Professor, research interests: laboratory testing, multi-scale modeling of THMC coupling in deep rock engineering. E-mail:
  • About author: HOU Hui-ming, male,born in 1989, PhD, Research interests: multi-physical coupling in underground engineering.
  • Supported by:
    This work was supported by the National Key R&D Program of China (2018YFC0809601), the National Natural Science Foundation of China(51779252) and the Major Projects of Technical Innovation in Hubei (2017AAA128).

Abstract: The high-level radioactive waste geological repository is in a multi-field coupling environment of thermo-hydro-mechanics (THM), and multi-field coupling analysis is required when performing safety assessment on the high-level waste repository. However, the excavation of the high-level radioactive waste repository causes the stress redistribution of the surrounding rock near the wall, consequently generates damage and results in changes in the thermal parameters (T), seepage parameters (H) and mechanical parameters (M) of the surrounding rock. These THM coupling parameters thus show inhomogeneous spatial distributions, which will have a significant impact on the THM coupling evolution process during the operational period of repository. By analyzing the coupling mechanism of thermo-hydro-mechanics of high-level radioactive waste repository, and the distribution and evolution law of surrounding rock damage in repository, the damage variable and damage evolution criterion are defined. The damage variable is related to thermal parameters, seepage parameters, mechanical parameters and multi-field coupling parameters (Biot coefficient, Biot modulus and temperature drainage coefficient) and then the damage of surrounding rock is linked with thermo-hydro-mechanical fields. An elastoplastic damage thermo-hydro-mechanical multi-field coupling numerical model is established. Then, the established model is used to simulate the surrounding rock heating test of the high-level waste geological repository in Mont Terri, Switzerland. The numerical and experimental values are compared, the effect of excavation-induced damage on evolution of temperature field, seepage field and stress field are discussed, and the evolution law of excavation-induced damage under multi-field coupling is also analyzed.

Key words: high-level radioactive waste, barrier system, multiphysics coupling problem, elastoplastic, excavation damage