Georadar investigations on dam in India

NGI will make georadar investigations of the dam core of the newly built Tehri Dam, 200 km north of New Delhi. The 261 m highTehri Dam is number eight on the list of the highest dams in the world.

In connection with an institute cooperation project between NGI and CSMRS (Central Soil and Material Research Station) at the Water Resource Ministry India, GPR tests are recommended for the quality control of the core of the newly built Tehri Dam. At present, the dam core is in perfect condition. So the coming test is only a reference test for the comparison with future tests for monitoring of the dam core. NGI plans to use a pair of 1.2m antennas for the main test, but will also bring a pair of flexible length of antennas for additional tests if necessary.

The antenna technology is vital for the success of georadar use. NGI's georadar uses frequency modulated antennas, for sending radar signal down into the ground. The reflected signals provides a picture of the subsurface. Depending on the ground conditions, the frequency may be altered to obtain better results. Georadar investigations can identify objects in the ground, identify layering and cracks and changes in subsurface features. For more information, please see link to the pdf-article "Georadar merits".

NGI's expert advisor,
Dr. Kaare Høeg, during a field trip at the
construction site for Tehri Dam