Cell for the triaxial stress testing of a rock sample and a testing method using such a cell
AssigneeInstitut Francais du Petrole
InventorsJean-Paul Sarda, Guy Grard
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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.
Claims10
A cell for the triaxial stress testing of a rock sample, comprising a central body including a means for exerting lateral stresses on said sample and a means for exerting a vertical pressure on a section of the sample, said means for exerting lateral stresses comprising a membrane enclosing said sample, said cell further comprising means for measuring the deformations of the sample related to the stresses which are applied thereto, wherein said membrane positioned within the central body has an external surface that comes into contact with said body and has a central longitudinal opening in which the sample is positioned, said sample being in contact with an inner surface of the membrane which defines the longitudinal opening and said membrane comprising a resilient member having a hollow internal volume forming a chamber for confinement of a fluid introduced into the chamber through an orifice connected to said membrane.
A method for the triaxial stress testing of a rock sample using a triaxial testing cell, wherein:
- a membrane is positioned within a body of the cell so that external walls of said membrane bear against said body,
- a sample to be tested is placed in a central opening of said membrane, so that walls of the sample are in contact with said membrane,
- a fluid is injected into a confinement chamber defined within said membrane for exerting a homogeneous lateral confinement pressure over a whole lateral surface of the sample,
- displacement sensors mounted on stirrup elements of the cell are set to a zero position,
- a vertical pressure is exerted on the sample by the action of means for exerting a vertical pressure on a section of the sample within the central opening, and
- displacement of said sample is measured by the sensors.
Dependencies are inferred from the claim text.