GRP Facilities

CNDE has built a test levee to develop a capability assessment tool to better understand and characterize the potential of ground penetrating radar to develop an inspection for earthen levees and dams.  A temporary test levee with known defects located throughout the structure provides a unique opportunity to quantify and calibrate the GPR signal under various soil and climate conditions.   The facility was designed and built using the same methods employed in the construction of levees to accurately depict conditions found in the field.  The test levee is co-located with CNDE at the Applied Sciences Complex.    The size of the test levee is approximately 10 feet in height and width at the crest of the structure with an appropriate corresponding slope on the sides of the structure.  The length of the test levee is approximately 21 feet, not including the access ramp at one end of the test levee to allow access with the GPR equipment.

levee side-600x170

 

levee end

 

View looking down on the Test Levee showing implanted defect diameters and depths

levee flaws-600x295

Table of Defect size and Depth Location

Size (in) Depth (ft) Conductive Non-Conductive
1″ 2′ X
2″ 2′ X
2″ 4′ X
4″ 4′ X
6″ 10′ X
10″ 10′ X
1″ 2′ X
2″ 2′ X
2″ 4′ X
4″ 4′ X
6″ 10′ X
10″ 10′ X

CNDE GPR Antennas along with their depths of penetration and typical use

Depth Range Primary Antenna Choice Secondary Antenna Choice Appropriate Application
(approximate)
0-1.5 ft  0-0.5 m 1600 MHz 900 MHz Structural Concrete, Roadways, Bridge Decks,
0-3 ft 0-1 m 900 MHz 400 MHz Concrete, Shallow Soils, Archaeology
0-12 ft 0-9 M 400 MHz 200 MHz Shallow Geology, Utilities, UST’s, Archaeology
0-25 ft 0-9 m 200 MHz 100 MHz Geology, Environmental, Utility, Archaeology

gpr equip-600x358

CNDE has acquired state-of-the-art ground-penetrating radar (GPR) equipment.