We report the emergence of anomalous (non-Fickian) transport through a rough-walled fracture as a result of increasing normal stress on the fracture. We show that the origin of this anomalous transport behavior can be traced to the emergence of a heterogeneous flow field dominated by preferential channels and stagnation zones, as a result of the larger number of contacts in a highly stressed fracture. We show that the velocity distribution determines the late-time scaling of particle spreading, and velocity correlation determines the magnitude of spreading and the transition time from the initial ballistic regime to the asymptotic anomalous behavior. We also propose a spatial Markov model that reproduces the transport behavior at the scale of the entire fracture with only three physical parameters. Our results point to a heretofore unrecognized link between geomechanics and particle transport in fractured media.
Bibliographical noteFunding Information:
This work was funded by the U.S. Department of Energy through a DOE CAREER Award (grant DE-SC0003907 ) and a DOE Mathematical Multifaceted Integrated Capability Center (grant DE-SC0009286 ). P.K.K. gratefully acknowledges support from the Korean Ministry of Land, Infrastructure and Transport ( 16AWMP-B066761-04 ). Data used in this manuscript can be obtained from the corresponding author ( firstname.lastname@example.org ).
- anomalous transport
- groundwater flow
- spatial Markov model