Hydro-mechanical-chemical coupled simulation of the Groundwater REcovery Experiment in Tunnel (GREET); Prediction of geoenvironmental disturbance during tunnel excavation

Ozaki, Yusuke  ; Ishibashi, Masayuki; Onoe, Hironori ; Iwatsuki, Teruki  

We perform a prediction analysis of the Groundwater Recovery Experiment in Tunnel (GREET) that is an ongoing experiment project in Mizunami Underground Research Laboratory for undearstanding of geoenvironmental recovery after closure of subsurface facility. The hydro-mechanical-chemical coupled behavior of subsurface environment during the excavation of research tunnel for GREET is simulated. For this prediction study, we build a hydrogeological model based on information of fracture with Discrete Fracture Network model. The model is converted to equivalent continuous porous model (ECPM) for Finite Element modelling. We compare the predicted results of drawdown of hydraulic pressure, inflow into tunnel and variation of Cl concentration during excavation.