Abstract：This paper presents the development of thermo-hydro-mechano-chemical(THMC) studies on excavation damage zone(EDZ) in crystalline rocks，which is an important part of international cooperative project DECOVALEX-THMC，denoted TASK B. The basic idea of THMC coupling studies of EDZ in crystalline rock is introduced. The mechanism of EDZ formation and evolution can be characterized and analyzed based on typical experiments carried out in underground laboratory(for example，Äspö HRL). Then the THMC models of elasticity，elastoplasticity and visco-elastoplasticity and so on can be built and the associated codes can be developed. The behaviors of THMC coupling in EDZ of crystalline rock will be analyzed by using these codes. Comparisons of the results between each research group in different countries and technical evaluation on the models that each group used will be conducted by experts or scientists majored in this field. By doing so，the model and method that each group developed will be updated according to the evaluation results and the THMC model in EDZ of crystalline rock will be obtained appropriately. The guidance document of THMC studies in EDZ of crystalline rock can be compiled based on the work described above；and it can provide technical supports for the studies of underground disposal for high-level nuclear waste disposal.
