Development of solute transport modelling for multiple flow paths around the faults in mudstone

Takeda, Masaki ; Ono, Hirokazu ; Tachi, Yukio  ; Murayama, Shota*

This study characterized the solute transport properties of fault zone fractures in a mudstone by applying the modelling approach, which could be addressed heterogeneity in the fault zone fractures. Breakthrough curves (BTCs) derived from dipole tests were simulated with GoldSim code and the model assuming three flow paths individually consisted in the flow and stagnant domain. This modelling approach gave good agreement with the BTCs of uranine and Mo for pulse injection tests. However, there are some gaps of BTCs trend of uranine, Mo and Cs for continuous tests between in situ and simulation results. These gaps can be caused by larger tracer recovery in simulation results than tests results. We will continue to develope the more realistic model and optimal model parameters that can be appropriately treated to uncertainty of transport paths.