Power law breakthrough curve tailing in a fracture: The role of advection

JOURNAL OF HYDROLOGY

卷:525

Article

Fiori, Aldo¹  Becker, Matthew W.² 

[1] Univ Rome Tre, Dipartimento Ingn, I-00146 Rome, Italy

[2] Calif State Univ Long Beach, Dept Geol Sci, Long Beach, CA 90840 USA

关键词: Solute transport;    Single fracture;    Breakthrough curve;    Powerlaw tailing;   

DOI  :  10.1016/j.jhydrol.2015.04.029

来源: Elsevier

【 摘 要 】

We offer an explanation of the strongly tailed solute breakthrough curve typically observed when a tracer test is conducted in fractured bedrock. In this example, we limit the model to a single planar fracture of varying aperture. Flow heterogeneity derives from variable fracture aperture, which implies variable transmissivity (T). The analysis employs a physically based model well-suited to strong heterogeneity and relies only upon advective transport. The purely advective model is able to explain a power-law trend of magnitude 2 to 3 in the breakthrough curve tail; a range that has been found in field tracer experiments. The principle cause of this trend is the comparatively slow, transport in zones of small transmissivity (tight aperture). Slow advection occurs when either heterogeneity (variance of In T) is strong or when the assumed heterogeneity distribution is non-Gaussian. Thus, we link breakthrough tailing to the statistical parameters for the transmissivity field. (C) 2015 Elsevier B.V. All rights reserved.

【 授权许可】

Free