SU1399662A1 - Device for testing brittle rock samples in uniaxial extension - Google Patents

Abstract

The invention relates to physico-mechanical testing of rocks under laboratory conditions. The device contains a cylindrical body (K) 1 for installing sample 2 of rock, centering elements in the form of conical collets 3. On sample 2, sealing rings 4 and bushings 5 with conical inner / 2 C /) are installed

Description

by hand. The latter are located on opposite sides of K 1 with the possibility of movement. On the inner surface K 1 in its central part there is a protrusion 6 with conical surfaces 7.8 facing the ends of K 1. Collets 3 are installed between surfaces 7 and 8 and sample 2. Rings 4 are placed; collets 3 and ends of sleeves 5 After I securing sample 2, a tensile force is applied to it. When loading sample 2 and deforming, the collet 3 is released from the pre-pressure load and does not act on the sample 2. Thus. the possibility of the occurrence of stress concentration at the points of contact of the collets 3 with samples 2 is excluded. When the sample 2 is destroyed, the elements of the device are not damaged, since the entire system remains connected by cables. 1 il.

one

The invention relates to physicomechanical tests of mining conditions under laboratory conditions, and specifically to the study of the strength and deformation properties of mining rocks under uniaxial stretching.

The purpose of the invention is to improve the measurement accuracy.

The drawing shows a diagram of the proposed device.

A device for testing fragile gbrous rocks for uniaxial stretching; it contains a cylindrical body 1 1 for installing sample 2 rocks, centering elements in the form of cocks 3, mounted on sample 2 sealing rings L and bushings 5 mounted on opposite sides body 1 is movable. On the inner surface of the housing 1 in its central part there is a protrusion 6 with conical surfaces 7.8, facing HbDffi towards the corresponding ends of the housing 1, and bushings 5 are made with conical internal surfaces. Cone collets 3 are installed between the conical surfaces 7.8 of the protrusion 6 of the housing 1 and the rock specimen 2. Sealing rings 4 are placed between the conical collet 3 and the ends of the sleeves 5, The sleeves 5 are fitted with nuts 9 and 10 with locking bolts 11, respectively, and the ends of the body 1 have flanges 12 In the cavity between the sleeves 5 and sample 2 there is placed cementing material 13.

The device works as follows.

To prepare the device for testing the sample 2 rock body

1, one of the flanges 12 is mounted on a flat surface (not shown), sample 1 is lowered into case 1, so that sample 2 was fixed in the required position (according to

height) position, it is mounted on a stand (not shown), while the middle of the sample 2 in height must coincide with the middle part of the housing 1. After this, the conical

the surface 7 of the protrusion 6 down conical collet 3 and the sealing ring 4 mounted on the sample 2.

Then, a sleeve 5 with a nut 9 is inserted into the opening of the housing 1. Pressing the upper end of the nut 9 transfers pressure to the sealing ring 4 and the tapered collets 3, after which the position of the sleeve 5 in the housing is fixed

1 by bolts 11. In this case, the sealing ring 4, deformed under pressure, tightly closes the gap between the sleeve 5 and the sample 2, and the conical collets 3, surrounding the sample 2, center the upper end of the sample 2 in the housing 1. Thereafter 1 turn and repeat the described operations at the other end of sample 2,

Thus, prior to cementing, the sample 2 is centered relative to the longitudinal axis of the housing 1, and the sealing rings 4 are under pressure (pre-pressing force), reliably closing the gaps between the sample and the sleeves 5.

The cementing material 13 is poured into the cavity between the conical surfaces of the sleeves 5 and sample 2 through windows in nuts 9,10 and sleeves 5. Wood's alloy is used as a cementing material (mp 60-70 ° C). When cooling (5–10 min), the Wood alloy fastens the side surface of sample 2 with the inner conical surfaces of bushings 5. First, one end of sample 2 is cast, and after alloying, the device is inverted and the other end of the sample is cast. 2

After cementing, the bolts 11 are lowered so that the size between the ends of the bolts 11 is larger than the outer diameter of the flanges 12.

When testing, nuts 9 and Yu are screwed into the loading heads with cables or rods (not shown) and secured to the grips of the testing machine (not shown), after which they turn on the testing machine and apply a tensile force to the sample 2. When loading the sample 2 and its deformation, the conical collet 3 is released from the pre-pressing load and does not act on the sample 2, thus eliminating the possibility of stress concentrations occurring in the - places of contact of the conical collet 3 with the sample 2.

When sample 2 is destroyed, the elements of the device are not damaged, since the entire system remains connected

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cables, body 1 and bolts 11 (flanges 12 and bolts 11 do not allow the system to disintegrate).

After sample 2 is destroyed, the device is freed from the grips of the testing machine, the bolts 11 are unscrewed, the sleeves 5 with the nuts 9,10 are removed from the body 1, and the sleeves are disconnected

10 5 and nuts 9,10.

Then the pressure (compression) from the testing machine alternately load the parts of sample 2 and push them out of the sleeves 5 together with the alloy

-15 wood; which is separated from sample 2 for reuse.

Claims (1)

Invention Formula 2Q A device for testing fragile rocks for uniaxial stretching, containing a cylindrical body for mounting a sample of rock, centering elements in the form of 25 conical collets mounted on specimen o-rings and bushings with conical inner surfaces mounted on opposite sides of the housing with the possibility movement; distinctively e with the fact that, in order to measure accuracy, on the inner surface of the body in its central part there is a protrusion with conical surfaces facing the ends of the body, while the conical collets are installed between the conical surfaces of the protrusion to the urpus and the image, and O-rings are placed between the cone studs and the ends of the sleeves.