Method and apparatus for determining tensile strength
AssigneeThe United States of America as represented by the United States Department of Energy
InventorJoe L. Ratigan
Life of this patent
Estimating the term…
Abstract
A method and apparatus for determining the statistical distribution of apparent tensile strength of rock, the size effect with respect to tensile strength, as well as apparent deformation modulus of both intact and fractured or jointed rock. The method is carried out by inserting a plug of deformable material, such as rubber, in an opening of a specimen to be tested. The deformable material is loaded by an upper and lower platen until the specimen ruptures, whereafter the tensile strength is calculated based on the parameters of the test specimen and apparatus.
Claims10
In a method for the determination of apparent tensile strength of rock, the improvement including the steps of:
- forming a non-inflatable, substantially solid, cylindrically shaped deformable member so as to have a length less than a length of an opening extending through a rock specimen to be tested,
- inserting the deformable member into the opening extending through the specimen to be tested,
- providing load applying means configured to have protruding portions thereon for extending into the opening of the rock specimen,
- positioning the load applying means on opposite sides of the deformable member such that the protruding portions of the load applying means abuts opposite ends of the deformable member, and
- applying a force to the load applying means causing longitudinal compression and radial expansion of the deformable member which causes fracturing of the rock specimen.
A rubber fracturing method for determining the tensile strength of rock including the steps of:
- inserting a substantially solid rubber member in an aperture in a rock disk specimen to be tested such that the rubber member length is less than the length of the aperture in the rock disk,
- positioning the rock disk specimen between a pair of platens having protruding sections thereof such that the protruding sections of the platens extend into the aperture in the rock disk and are in abutment with opposite ends of the rubber member, and
- applying force to the rubber member through at least one of the pair of platens causing at least radial expansion of the rubber member resulting in fracturing of the rock disk specimen.
An apparatus for rubber fracturing rock disks to determine the apparatus tensile strength of the rock comprising:
- a substantially solid cylindrically shaped deformable rubber member having opposite end surfaces and adapted to be inserted into a central borehole of a rock disk to be tested,
- a first platen having a protruding section adapted to be inserted into the central borehole of a rock disk to be tested and in abutment with one of said end surfaces of said deformable member,
- a second platen having a protruding section adapted to be inserted into the central borehole of a rock disk to be tested and in abutment with an opposite one of said end surfaces of said deformable member, and
- means for applying a load to said deformable member through at least one of said end surfaces by at least one of said platens causing said deformable member to be compressed longitudinally and expanded radially, thereby placing the rock disk to be tested under tension and resulting in fracturing of the rock disk.
Dependencies are inferred from the claim text.