http://catalogue.nrcan.gc.ca/opac/extras/unapi?id=tag:catalo...

Comparison of rock mass deformabilities determined using large flat jack technique and plate jacking test at two dam sites. (Comparaison de deformabilites des massifs rocheux determinees par des essais de "Flatjack" large (verin) et d'essai de plaques portantes a deux chantiers de barrage).

http://waterresources.rajasthan.gov.in/6facilities.htm
plate jacking test (PJT)
The insitu rock stress is determined by using the flat jack equipment.

http://webcache.googleusercontent.com/search?q=cache:MsW28ut...

The deformation modulus of rock mass is an important input parameter in any analysis of rockmass behaviour that includes deformations. Many different methods as field tests are developed for assessing this vital parameter directly. On the other hand, these field tests are often time consuming, expensive and the reliability of the results of these tests is some times questionable. Consequently, several authors and researchers have proposed empirical relationship for estimating the value of rock mass deformation and elastic modulus on the basis of characterization schemes such as GSI. The plate jacking test (PJT), where the deformations are measured by extensometers in drill holes which gives generally the best results, has been carried out in Parsian dam site,

http://books.google.co.in/books?id=Ls1MSleftQ8C&pg=PA245&lpg...

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Note added at 46 mins (2010-12-24 17:36:09 GMT)
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some more info for reference - may be relevant
http://www.rockmass.net/rmi/rockmass/deformation_modulus.pdf...

A source to create confusion about the measurements and values of deformation modulus comes from poor definition or wrong term for the type of test performed. The plate loading test (PLT) and plate jacking test(PJT) are especially sensitive to this, as both are often named plate bearing test. But only PJT uses extensometer measurements in bore holes.

IN SITU MEASUREMENTS OF DEFORMATION MODULUS
All in situ deformation tests are expensive and difficult to conduct. They are mostly conducted in special testadits or drifts excavated by conventional drill and blast having a span of 2 m and a height of 2.5 m. The length of such adits varies with local conditions from some ten metres to several hundred metres. Initial preparations at each test site are particularly time consuming. The interpretation of measured in situ data is another difficult aspect, which requires experience from those involved. Today, the following three types of in situ tests are mostly used to determine the modulus of deformation:
1. Plate jacking tests (PJT)
Two areas diametrically opposite in the test adit are loaded simultaneously, for example using flat jacks positioned across the test drift as shown in Figure 2, and the rock displacements are measured inboreholes behind each loaded area.
2. Plate loading tests (PLT)
While the PJT records the displacements in drill holes beyond the loading assembly of flat jacks, the PLT measures the displacements at the loading surface of the rock, as shown in Figure 2.
3. Radial jacking tests (Goodman jack test)
The Goodman jack consists of two curved rigid bearing plates of angular width 90o which can be forced apart inside an NX size bore hole by a number of pistons. Two transducers mounted at either end of the 20 cm long bearing plates measure the displacement.
In addition to these three types the following in situ deformation tests can be used:−
flat jack tests;
− cable jacking tests;
− radial jack tests;
− dilatometer tests;
− pressure chamber.