The excavation damaged zone is still challenge in modeling up to now. The explicit introduction of cracks in the numerical simulation may be suitable for a few of cracks but it is difficult to handle if the number of cracks increases significantly. Another method to solve this issue is to replace the excavation damaged zone by an equivalent material obtained from the homogenization technique. The objective of this paper is comparative study of two methods, equivalent material by Eshelby’s solution and crack explicit model by assembling cracks individually in the framework of hydro-mechanical coupling. The comparison is implemented by home code in DEAL.II with the advancement of coupling strategy, refinement technique for crack model.
During the processing of underground excavation, cracks occur in the surrounding porous media due to stress redistribution or loosening of supporting material, and this surrounding area is called an excavation damaged zone. In the isotropic material, radial cracks are controlled in the loading case and concentric cracks are developed in the unloading case (Zhu et al., 2015). There are some approaches for modeling hydro-mechanical behavior of cracked porous media around an underground excavation, for example cracks are accounted explicitly that is the first approach or an equivalent material represented by using homogenization technique that is the second approach. The sketched of two approaches is presented in Fig. 1. The first approach is challenge when a huge of cracks occurs. Therefore, this method is suitable in case the number of cracks is limited. There are plenty of studies in the first approach such as Pouya et al. (2012), Dang (2018, 2020). The second approach has an advantage of computational cost while the accuracy of homogenization technique is issued and challenged. In general, the second approach can be applied if cracks are small in compared with geometry dimension, for example in Torbica and Lapcevic (2015). The homogenization technique presented in Dormieux et al. (2006) will be applied although the condition of a macroscopic scale infinitively large than the microscopic scale required for homogenization approach is not satisfied. Some studies are try to take the cracks into the porous media such as Pouya et al. (2012), Zhu et al. (2015).
