Abstract: The present invention provides a cell for the triaxial stress testing of a rock sample, comprising a central body in which is placed a membrane enclosing said sample and exerting lateral stresses thereon, as well as a vertical pressure means acting on a section of the sample, said cell further comprising means for measuring the deformations of the sample related to the stresses which are applied thereto. The membrane has a central lateral opening in which the sample is introduced, a lateral external surface coming into contact with the body of the cell and a hollow internal volume forming a chamber providing confinement by means of a fluid introduced through an orifice.

Abstract: Device for carrying out tests on materials such as rock samples for example, on which triaxial stresses are exerted.The device comprises an extended body with a central cavity where a first part (6) of a sonic sonde, a sole piece (9) carrying a cubic sample (12) for example, jacks (13) which are introduced along the lateral faces of the sample by connecting them with channels (25) supplying fluid under pressure are successively placed. A centering piece (27) containing a box (26) for another part (28) of the sonic sonde and elements (31, 32) forming a cover are placed above. A piston (35) allows to apply stresses to the sample by means of the box (26). Lateral sensors (22) pick up the displacements of the sample.Application to the examination of rocks taken from a subterranean formation for example.

Abstract: A device and method are provided for measuring the deformations of a sample, with the deformations resulting more particularly from the relaxation of the stresses to which the samples were subjected prior to the measurement, and with the sample having an axis corresponding to a main deformation direction. The device comprises at least five displacement sensors each having a measurement direction, with the measurement directions being substantially perpendicular to the axis of the sample.

Abstract: A device and method for measuring the deformations of a sample, which deformations particularly result from the relaxation of the stresses to which the samples was previously subjected. The device and method include the use of a cell inside which the sample is placed with the cell containing a thermal mass whose heat capacity and/or thermal conductibility are appreciably greater than those of air under normal temperature and pressure conditions.