Evaluation of geophysical methods to characterize alluvial soils in the arid environment

Non-intrusive geophysical investigations, both seismic and electrical, were performed at several locations on the Las Vegas Springs Preserve in Las Vegas, Nevada, along with intrusive drilling. These investigations were conducted to determine whether it is possible use geophysical methods to detect piping-induced cavities and shallow inclusions such as calcific nodules and horizons known as caliche in dry, desert soil, while at the same time characterizing the mechanical structure of the soil and distribution of soil moisture for engineering purposes. The geophysical methods used were the Spectral-Analysis-of-Surface-Waves (SASW) method, surface-based seismic cavity detection, multi-electrode electrical resistivity, and electromagnetic conductivity. The results of the geophysical measurements across the site were compared to each other, and to the ground truth obtained through intrusive drilling. The seismic and electrical signature of a known air-filled fissure was also established, and was used for comparison to the results obtained throughout the Preserve. The SASW method was successful in characterizing the complex layered geometry of the soil. The electrical resistivity method successfully distinguished between dry soils at shallow depths, and moist and wet soils beneath. The surface-based seismic cavity detection and the electrical resistivity methods were also used successfully for cavity detection, and it is concluded that voids of engineering significance would have been detected if they had been present. The electromagnetic conductivity method was not successful in detecting voids, but proved to be a valuable preliminary reconnaissance tool.

Name thesis:degree_name

Master of Science (MS)

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Civil and Environmental Engineering

Grantor dc:publisher

University of Nevada, Las Vegas

Year

2001

Author dc:creator

• Sundquist, Bjorn E

Contributors dc:contributor

• Barbara A. Luke

Statement dc:rights

• IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

Language dc:language

English

Identifier

https://oasis.library.unlv.edu/rtds/1341

OAI identifier oai:identifier

oai:oasis.library.unlv.edu:rtds-2340