Geophysical Methods, detecting voids in clayey material 3

[TPK06]

I'm looking for any tips regarding subsurface site assessment using geophysical methods.

What is the best method out there for detecting voids & anomolies in a dike built from clayey material? I only need to go to a depth of 25 - 30 feet. (I do plan on "ground truthing" with borings.)

I've got a copy of the ASTM that deals with this issue (D 6429), but any practical knowledge is appreciated.


Thanks!

 

[oldestguy]

I'd check out manually activated seismic gear also. You would want a scope read out method so you can see faint echos. Then calibrate with borings. You are likely to be disappointed with resistivity.

 

[BigH]

I suggest that you also consider ground penetrating radar; again with any anomolies confirmed by drilling.

 

[jdonville]

See also FHWA Geotechnical Engineering Circular No. 5, avialable from

http://www.fhwa.dot.gov/engineering/geotech/library_listing.cfm

and Application of Geophysical Methods to Highway Related Problems (FHWA-IF-021)

http://www.cflhd.gov/agm/SiteVersions/geotechPdf.pdf

Jeff

 

[Rockjoint]

With GPR, beware the common problems with clay soils.