Flat Jack
This is a direct method carried out in situ, it is a slightly destructive method since some modifications on the excavations wall must be made. This method is carried out on a wall of rock massif. The method involves identifying the force in the direction perpendicular to the jack installed in a slot made in the wall.

The objective of this essay is to determine the state of the compression efforts on a localized zone of a structure and to estimate the deformability characteristics (Poisson's modulus and deformability modulus) of the materials that make the structure.