SU1259035A1 - Installation for testing rock specimens - Google Patents

Description

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One of the examples is testing equipment, installations for testing rocks under complex stress conditions.

The aim of the invention is to approximate test conditions to a downhole method of loading a sample with an unevenly distributed lateral load along its length and simulating the pressing of a rock.

Fig. 1 is a schematic of the setup for testing rock samples; Fig. 2 shows a connection unit of a corrugated bellows.

The installation contains a test chamber 1 placed in a hollow cylindrical body 2 with an opening 3. The chamber communicates with the external space and the supporting insert 4, the lateral 5 and the front 6 elastic shoes filled with liquid and mounted on the test chamber .1. The piston .7 of the hydrojack, the body of which is the body 2, contacts the face shoe 6. The side shoes 5 have an annular shape and are placed in separate corrugations of the bellows 8 made up of ribs of different stiffness. The number of corrugations of the bellows 8 and their rigidity are selected from a predetermined number of side load increment steps. The bellows 8 is installed, coaxially with the test chamber 1 and rests on one end of the piston 7 of the hydraulic jack, the second - against the piston 9. The piston 9 is additional and has an orifice coaxial with the aperture 3 of the housing 2 and contains supporting pads; The clamp 4. The end shoe 6 interacts with the stop 10 fixed on the piston 7. The pump station 11 is connected by valves 12 and 13 to the cavity of the chamber, i.e. a piston jack 7 and 9. The cavity of the piston 9 is connected to an overpressure valve 14 with an adjustable response pressure. Test chamber 1 consists of an elastic coating placed inside two twisted cylindrical springs 15 inserted with FRIEND in the other with opposite naming directions. The outer spring 15 is in contact with the elastic shoes 5. The test sample 16 is placed inside the elastic coating of the chamber 1. The position 17 denotes the fur element. This may affect the test specimen, for example, the drill rod.

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The installation works as follows.

The pump station 11 is turned on. And with the valves 12 and 13 open, the piston cavities 7 and 9 are filled with the working fluid. The valve 13 is closed, the valve 14 is adjusted to the set response pressure. The station 11 is again switched on and the working fluid is pressurized in the cavity by the piston 7. Under the action of this pressure, the piston 7 moves and deforms BELLOW 8, the corrugations of the bellows 8 deform in proportion to their individual axial stiffness and compress the elastic shoes 5 located therein. The bearing shoe 5 transmits the pressure to the test chamber 1 and the sample 16 located therein. The pressure value in the liquid of the shoes is proportional to the deformation of the shoes and inversely depends on their stiffness. At the same time, when the piston 7 is displaced, the stop 10 deforms the end shoe 6, also filled with liquid, the pressure of which is transferred to the front part of sample 16. When the bellows 8 is deformed, there is some displacement r of its corrugation relative to the surface of the test chamber 1, and this displacement is partly due to spring slip 15 relative to each other, otherwise - in the deformation

35 elastic shoes 5. Sample 16 remains at this stage of loading motionless and rests on the perimeter of the end face in the insert 4. The area of the stop 10 in the area of its contact with the shoe 6

40 is selected so that by the time the specified lateral load distribution is reached, a predetermined amount of end force will be obtained. The moment of achievement of a given tensioned state of the sample is determined by the moment of operation of valve 14 as a result of reaching a predetermined pressure in the piston-piston cavity 9 with an increase in pressure under the piston 7. The pumping station 11 is turned off, and

sample 16 is under operation. The effect of unevenly distributed lateral load and end load of specified values. They begin to study the mechanical properties of a sample that is under a given complex, stressful state, for example, study the process of rock drillability.

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Under these conditions, the operation of the drill rod 17 inserted through the hole 3. At the desired time, the rock is pressed, the pump station 11 is turned on and pressure is pumped through the valve 12. The pressure above the piston 7 increases above the predetermined pressure. the piston 9 and the continuous actuation of the valve 14, as a result of which both pistons together with the bellows 8 and the sample 16 move in the direction of the open end of the sample 16 With a constant stressed state of the sample 16. When an obstacle arises samples were, for example, by the rod 17, the pressure under the piston 7 will increase, which will increase the lateral load on the load and the end of the sample as long as no obstacle to ustranits sample displacement. It is this situation that occurs in the face when the rock is pressed in the direction of the goaf, when the rock encounters resistance to pressing from the lining side, equipment, etc. After elimination of the obstacle, the sample returns to the initial stress state due to the operation of the valve 14. This is the operation of the installation when simulating bottomhole conditions -. With the valve 14 turned off and a constant increase in pressure under the piston 7, a proportional loading of the sample is obtained with uneven lateral reduction until the sample is destroyed. After the sample has been destroyed or its observation has been completed, the unit is decoupled and assembled for the next experiment, the bellows being 8 Kz corrugations and the shoes in accordance with the desired lateral load distribution. The ratio between the lateral and end loads is selected by changing the contact area of the stop 10 with the shoe 6, the position of the stop relative to the shoe. When placed in the hole of the piston 9 instead of the support insert 4 stop, similar to the stop 10 with the same shoe 6, the installation carries out tests for bulk compression with uneven or uniform (with the same bellows corrugations)

The lateral load, which models the height of the rock jack, ensures the proportion of the rocks in the massif.

The connection of the bellows of the bellows with the shoes is carried out under the action of

Native growth of the face load when the face shoe is deformed by the stop.

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elastic deformations of the shoes filled with liquid, for which the liquid in the shoes is at a small proportion of the atmosphere, excessive pressures. Such interaction of the shoe with the corrugation allows their large relative displacements. The opposite winding of the springs 15 provides minimal frictional force during the mutual sliding of the springs at the deflection of the bellows, as well as the uniform distribution of lateral forces on the sample surface in the zone of action of the individual bellows, which is facilitated by the use of an elastic shell between the sample and the springs. The different stiffness of the bellows is ensured by the difference in the diameters of their corrugations, the difference in the thickness of the walls of the corrugations.

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In the installation, the lateral load is created by a set of ring shoes distributed along the length of the sample and placed in the corrugations of the bellows with different stiffness of the ribs instead of the side shoes, each of which covers the sample along the entire length. This permits a load that is not uniform over the length of the specimen due to the different deformation of the specimens and the various pressures caused by this in each shoe. The different amount of deformation of the side shoes appears as a result of the difference in stiffness of the bellows ribs during deformation of its hydraulic jacks: the higher the stiffness of the rib, the less its deformation compared to other ribs experiencing the same effort from the hydraulic jack, the lower the pressure in its shoe and the smaller side load in the zone of sample contact with this shoe. Supply of the installation with an additional piston against which the second end of the bellows rests and in which a hole is made coaxial with the chamber opening and containing supporting bushings allows, if necessary, to displace the loading specimen in the direction of its open end. The sign of the shoe's interaction with the stop fixed on the hydraulic jack, with the load design adopted by the side load by shifting the hydraulic load of the end load when the face shoe deforms by the stop.

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Compiled by V.Petrova Editor V.Ivanov Tehred I.Popovich Proofreader S.Shekmar

Order 5104/35 Circulation 470Subscription

VNIIPI USSR State Committee

 for inventions and discoveries 113035, Moscow, Zh-35, Rauschska nab., 4/5

Production and printing company, Uzhgorod, Projecto st., 4

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Claims (1)

¢ 54) INSTALLATION FOR TESTING SAMPLES OF ROCKS, containing a hollow cylindrical body with holes in its ends, coaxially placed in it a test chamber for a sample, lateral and mechanical elastic shoes mounted on it, filled with liquid, a support insert installed in one of the openings of the body , a hydraulic jack, the piston of which is connected to the end shoe and a medium pressure source in communication with the chamber cavity, characterized in that, in order to bring the test conditions closer to the bottomhole by loading the sample unequally Roughly distributed along its length, the lateral load and simulate the extraction of the rock, it is equipped with an additional piston installed in the housing with a rod, in which a through axial hole is made, a bellows coaxially mounted on the chamber, composed of corrugations of different stiffness according to the number of lateral loading steps, one end of which abuts in the piston of the hydraulic jack, and the other in the additional piston, with a stop fixed on the piston of the hydraulic jack, the side shoes being circular and placed in separate bellows corrugations, op molecular liner mounted in an aperture of the auxiliary piston, the rod of which is omitted in another otvorstie housing and the piston hydraulic jack connected with an end abutment by the shoe. SU ,,, -1259035 A1