Sorbing tracer experiments in a crystalline rock fracture at Äspö (Sweden): 3. Effect of microscale heterogeneity

Abstract

We study the impact of microscale (10−3–10−2 m) heterogeneity in material and structural properties on sorbing tracer transport in a single crystalline fracture of the TRUE‐1 tests (mesoscale, 5 m) at Äspö (Sweden). The analysis is based on the microscale characterization results as presented in part 1 of this series. Our main objective in this last part of the series is to provide an independent interpretation (or “prediction”) of the effective parameters as estimated from calibration in part 2 by combining the data presented in part 1 with analytical and numerical transport modeling. We show here that the independent information from microscopic characterization can be used for “predicting” the effective diffusion time td reasonably well; a discrepancy is to be expected given the uncertainties of microscale retention properties, in particular of the sorption coefficient.