Geoelectric monitoring of seepage in porous media with engineering applications to earthen dams

A monitoring methodology is developed for investigating seepage and internal erosion in earthen dams with time-lapse measurements of self-potential anomalies associated with conservative salt and non-conservative heat tracer migration in the subsurface. The method allows for 1) detecting seepage zones in earthen dams and determining the preferential flow paths through seepage zones in a non-invasive manner from the ground surface, 2) monitoring the transient evolution of seepage path geometry, flow velocity, and permeability in real-time if high frequency measurements can be made, and 3) long-term non-invasive monitoring with wired or wireless sensors The method is first theoretically developed and tested in a laboratory using a conservative tracer, and then demonstrated at a 12 m high, 100 m long leaking earthen dam with complex, unknown seepage paths. The method is shown to be capable of rapidly detecting seepage zones discovered during a reconnaissance survey, and delineates the predominant seepage directions through the dam from the time-lapse self-potential anomalies. The time-lapse monitoring approach ensures improved spatial resolution, increased measurement frequencies, and improved data analysis capabilities relative to traditional approaches to seepage detection, and a cost-reduction for the application of this methodology is anticipated to follow advancements in wireless sensing and monitoring technologies. This method is designed to be a more cost-effective means of interrogating earthen dams and levees to answer questions such as: Is the dam safe? What are the geometries of the seepage zones inside of the dam, and over what spatial scale does anomalous seepage occur? What are preferential paths through the seepage zones? Is internal erosion actively occurring? At what rates are the geometries, permeabilities and flow rates of preferential seepage paths evolving?

Name thesis:degree_name

Doctor of Philosophy (Ph.D.)

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Geophysics

Grantor dc:publisher

Colorado School of Mines. Arthur Lakes Library

Year dc:date.issued

2013

Author dc:creator

• Ikard, Scott J.

Advisor dc:contributor.advisor

• Revil, André, 1970-

Committee members dc:contributor.committeemember

• Mooney, Michael A.
• Hale, Dave, 1955-
• Delborne, Jason
• Oden, Charles P.
• Minsley, Burke

• temperature
• earthen dams
• groundwater modeling
• imaging
• self-potential
• time-lapse monitoring

Statement dc:rights

• Copyright of the original work is retained by the author.

Language dc:language.iso

eng, English

Identifier

T 7368

OAI identifier oai:identifier

oai:repository.mines.edu:11124/12178