Physical Sciences and Mathematics Commons^™

Location Of Solution Channels And Sinkholes At Dam Sites And Backwater Areas By Seismic Methods: Part Ii, Vincent P. Drnevich, D. Raghu

KWRRI Research Reports

Four seismic field methods and a laboratory method are used to determine shear wave propagation velocities and shear moduli for two sites. The four seismic methods are: standard seismic refraction survey, down hole shooting refraction survey, transient Rayleigh wave survey, and crosshole shooting survey. A torsional resonant column apparatus was used for the laboratory tests. The cross hole shooting method gave the best results because direct measurements were made. Criteria for using this method are given. Methods which measure compression wave velocity give inconsistent results because the conversion to shear wave velocity is very sensitive to Poisson's ratio. Laboratory tests …

Location Of Solution Channels And Sinkholes At Dam Sites And Backwater Areas By Seismic Methods: Part I, Vincent P. Drnevich, S. R. Smith, E. P. Cleveland

KWRRI Research Reports

The basic concepts associated with the sledge hammer seismic refraction survey are reviewed and a modified version called down hole shooting is discussed. The latter method has distinct advantages for rock surface profiling. These include: calibration at the end points of the survey, measurement of vertical wave propagation velocities directly, and having a refracted wave ray path for almost the entire survey length.

The down hole shooting seismic refraction survey has been simulated with the digital computer. The method can handle any shaped rock surface profile and generates corresponding travel time curves for the forward and reverse profile surveys. This …