CN218330974U

CN218330974U - Rock direct tensile test device suitable for all compression testing machines

Info

Publication number: CN218330974U
Application number: CN202222299835.4U
Authority: CN
Inventors: 何鑫; 刘建锋; 唐一帆; 代晶晶; 梁超; 徐邓; 林浩; 杨建雄
Original assignee: Sichuan University
Current assignee: Sichuan University
Priority date: 2022-08-30
Filing date: 2022-08-30
Publication date: 2023-01-17
Anticipated expiration: 2032-08-30

Abstract

The utility model discloses a direct tensile test device of rock suitable for all compression testing machines, the loach carrying platform comprises a supporting fram, the fixed roof that is provided with in top of support frame, the top of roof is provided with the atress board, be provided with many vertical dowel bars on the atress board, the dowel bar vertically run through the roof and with roof sliding fit, just the lower extreme of dowel bar is provided with tensile base, be provided with on the tensile base with tensile base sliding fit's lower part bulb holder, the top of lower part bulb holder is provided with the blind groove of lower part centre gripping, be provided with the upper portion bulb holder with roof sliding fit on the roof, the bottom of upper portion bulb holder is provided with the blind groove of upper portion centre gripping, the central line in the blind groove of upper portion centre gripping coincides with the central line in the blind groove of lower part centre gripping. The utility model discloses reduced equipment cost when guaranteeing the test accuracy, simplified test operation, can realize the rock tensile test under the multiple condition.

Description

Rock direct tensile test device suitable for all compression testing machines

Technical Field

The utility model belongs to the technical field of the direct tensile test of rock, especially, a direct tensile test device of rock suitable for all compression testing machines.

Background

The tests of 3 kinds of mechanical parameters of compression resistance, tensile resistance, shearing resistance and the like of the rock are indispensable in all rock engineering construction. The tensile test of the rock sample is an important means for knowing the tensile load bearing capacity of the rock, and the tensile strength value of the rock is one of basic mechanical parameters in engineering construction and is very important for engineering design calculation. The existing methods for measuring the tensile strength value of the rock mainly comprise 2 methods of an indirect stretching method and a direct stretching method.

The indirect stretching method is also called Brazilian splitting method, because the operation is simple and convenient, the universality is wide, the method can be completed on all conventional material compression mechanical testing machines, and the method is also the only recommended test method in the national standard 'engineering rock mass test method Standard'. Although the Brazilian splitting method is a commonly recommended test method in ISRM and engineering rock mass test method Standard, the specific test methods are different and can be divided into a direct loading method, a filler strip method and an arc loading method.

The method recommended in the engineering rock mass test method standard is to add a metal pad strip between a test piece and a pressure head, and add a cork pad between the test piece and the pressure head for soft rock.

The contact part of the pressure head and the test piece is recommended to be set to be arc-shaped in ISRM, although the method ensures that the end part of the test piece is an arc-shaped compression area, the risk of breaking the end part of the test piece is reduced to a certain extent, the method requires that the radian of the pressure head needs to be matched with the size of a sample, the universality is not high, and the obtained tensile strength is high. Although the method is simple to operate and can be carried out on all material compression mechanical testing machines, the method has the following defects on the whole: (1) The accuracy of the measured tensile strength is low and still cannot be avoided under the influence of an end loading area; (2) In the splitting process, it is difficult to ensure that the splitting surface is along a preset loading surface; (3) It cannot be guaranteed that the cleavage plane must be the fracture plane with the smallest bearing capacity, especially for rocks with obvious bedding and defects. So that the indirectly measured tensile strength value cannot completely reflect the real situation.

In order to solve the problem that the indirect tensile test result cannot completely reflect the real situation, the direct tensile method is used for testing the tensile mechanical property of the rock. However, the direct tensile method has high requirements on the tensile function of the test equipment, so that the test cannot be performed by using a common compression mechanical testing machine, and the applicability is low. In order to test the tensile mechanical property of rocks under different conditions, the applicant combines the direct tensile function of the internationally most advanced MTS815 rock mechanical test system, solves part of problems in the test, and obtains a plurality of utility model patent authorizations such as ZL200610022224.8, US7624647B2, ZL201510068200.5, ZL201510068186.9, US9488560B2, US9488559B2 and the like respectively. However, for the direct tensile rock mechanical property test, the following disadvantages still exist: (1) The performance requirement on mechanical testing equipment is high, and the device is developed in a conventional material testing machine, so that the popularization is low; (2) The MTS815 tester is used for carrying out direct tensile test, the loading part is very complicated to disassemble and assemble in the test process, multiple persons are required to complete the test cooperatively, and the whole process is time-consuming and labor-consuming; (3) The loading parts needing to be disassembled and assembled are all steel modules, the size is large, the weight is heavy, and serious potential safety hazards of equipment damage or personnel injury exist in the disassembling and assembling process; (4) The installation and test process of direct stretching is complicated, at least 2 persons are needed to complete the installation and test process, and a large amount of labor is still needed to be consumed; (5) In the test, because a plurality of loading cushion blocks are required to be piled up and 2 long loading chains are respectively connected with the stretching end part of the rock 2, the test result is easily influenced due to the occurrence of eccentric stretching force; (6) At present, direct tensile test of rocks under triaxial lateral compressive stress cannot be realized, and direct tensile test of rocks under two axial direct applied compressive stresses cannot be realized.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a rock tensile test device can guarantee to take place to destroy along the position that the sample bearing capacity is minimum, reduces test cost when guaranteeing to measure the accuracy to rock tensile test and two axial under direct application compressive stress rock tensile test under the triaxial side direction compressive stress can be used to.

The purpose of the utility model is realized like this: rock tensile test device, the loach carrying platform comprises a supporting fram, the fixed roof that is provided with in top of support frame, the top of roof is provided with the atress board, be provided with many vertical dowel bars on the atress board, the dowel bar vertically run through the roof and with roof sliding fit, just the lower extreme of dowel bar is provided with tensile base, be provided with on the tensile base with tensile base sliding fit's spherical first holder in lower part, the top of spherical first holder in lower part is provided with the blind groove of lower part centre gripping, be provided with on the roof with the spherical first holder in upper part of roof sliding fit, the bottom of spherical first holder in upper part is provided with the blind groove of upper portion centre gripping, the central line in blind groove of upper portion centre gripping coincides with the central line in the blind groove of lower part centre gripping.

Further, the support frame includes base and the many stands of vertical setting on the base, the roof is fixed in the upper portion of stand through first fixation nut.

Further, base and roof all are fillet triangle-shaped, the stand is three.

Furthermore, the stress plate and the stretching base are in a shape of a rounded triangle, and the number of the dowel bars is three.

Further, the stretching base is fixed at the lower end of the dowel bar through a second fixing nut.

Furthermore, the lower extreme of dowel steel is provided with the horizontally connecting rod, the lateral wall of tensile base is provided with the embedding hole, the connecting rod is connected with the embedding hole plug-in connection.

Furthermore, the edge of the stretching base is provided with a connecting notch, the lower end of the dowel bar is provided with a connecting block matched with the connecting notch, and the connecting block is positioned in the connecting notch and detachably connected with the stretching base.

Further, the upper clamping blind groove and the lower clamping blind groove are circular holes or rectangular holes.

The beneficial effects of the utility model are that: 1. the utility model discloses only need have conventional material testing machine can carry out rock tensile test, need not to add solitary tensile test equipment, the universality is wide, has overcome the defect that traditional direct tensile method equipment is with high costs.

2. The utility model discloses a press and change the direct tension method of drawing, can guarantee to take place to destroy along the position that the sample bearing capacity is minimum, overcome the defect that traditional indirect tension method accuracy is low.

3. The device is simple in structure, mainly comprises a steel structure, and is low in cost compared with similar tensile test equipment; the volume is small, the weight is light, and the movement is convenient; the operation is convenient and labor-saving, the test can be carried out by one person, and the use cost is reduced; accidents such as equipment accidental damage, personal safety of operators and the like caused by disassembling and assembling heavy loading parts are avoided, and the safety is high; the stretching structure is compact, and the eccentric stress problem possibly existing in superposition of a plurality of components is avoided.

4. Because the utility model discloses compact structure, the volume is less, can arrange current triaxial testing machine pressure chamber in inside, has solved the difficult problem that the direct tensile test of rock can not develop under triaxial lateral stress.

5. The utility model discloses a posture is pressed and is changeed and draw device has solved the direct tensile test of rock and can not directly exert the difficult problem that develops under compressive stress at two loading axle directions, can directly use with the cooperation of current true three-dimensional load test machine, accomplishes the direct rock tensile test who applys compressive stress under two loading axle directions.

Drawings

FIG. 1 is a schematic top view of a first embodiment;

FIG. 2 is a schematic cross-sectional view of I-I of FIG. 1;

FIG. 3 is a schematic front view of the second embodiment;

FIG. 4 is a schematic front view of the third embodiment;

reference numerals: 1-a base; 2, a column; 3-a top plate; 4-a first fixing nut; 5, a stress plate; 6-dowel bar; 7-stretching the base; 8-a second fixing nut; 9-a lower spherical head holder; 10-oil pressure protection heat shrinkage film; 11-upper ball head holder; 12-test sample.

Detailed Description

The present invention will be further explained with reference to the drawings and examples.

Example one

As shown in fig. 1 and 2, the utility model discloses a direct tensile test device of rock suitable for all compression testing machines, which comprises a supporting rack, the fixed roof 3 that is provided with in top of support frame, the top of roof 3 is provided with atress board 5, be provided with many vertical dowel steel 6 on the atress board 5, dowel steel 6 vertically runs through roof 3 and with roof 3 sliding fit, and the lower extreme of dowel steel 6 is provided with tensile base 7, be provided with on the tensile base 7 with tensile base 7 sliding fit's spherical head holder of lower part 9, the top of spherical head holder of lower part 9 is provided with the blind groove of lower part centre gripping, be provided with on the roof 3 with the spherical head holder 11 in upper portion of 3 sliding fit, the bottom of the spherical head holder 11 of upper portion is provided with the blind groove of upper portion centre gripping, the central line in the blind groove of upper portion centre gripping coincides with the central line in the blind groove of lower part centre gripping.

The supporting frame is used for supporting other components, and can adopt frames of various structures, preferably, the supporting frame comprises a base 1 and a plurality of upright posts 2 vertically arranged on the base 1, and a top plate 3 is fixed on the upper parts of the upright posts 2 through first fixing nuts 4. The base 1 is a metal plate with a certain thickness, and the upright post 2 can be a cylindrical metal rod piece or a hollow pipe. The lower end of the upright post 2 can be welded with the base 1, and can also adopt common connection modes such as thread fit and the like. The upper portion of the stand column 2 is provided with external threads, the positioning can be carried out by arranging the first fixing nut 4 on the upper surface and the lower surface of the top plate 3, a supporting step can also be arranged on the outer wall of the upper portion of the stand column 2, the top plate 3 is arranged on the supporting step, the first fixing nut 4 is arranged on the upper surface of the top plate 3, and the top plate 3 is locked. Roof 3 demountable installation can be torn down roof 3 during the removal, also is convenient for adjust the height of roof 3.

The base 1 and the top plate 3 may be square, circular, triangular, etc., as shown in fig. 1, preferably rounded triangular. The number of the upright posts 2 can be 3, 4 and the like, preferably 3, and the top plate 3 can be positioned more stably and is better fixed. And adopt the less stand 2 of quantity, the space between the stand 2 is bigger, conveniently installs other measuring transducer and reserves operable space on being tested the rock sample.

The stress plate 5 directly receives compressive load, and the stress plate 5, the dowel bar 6 and the stretching base 7 form a stretching frame which converts the compressive load into the stretching load, and the upper end of the dowel bar 6 can be connected with the stress plate 5 in a welding manner, and can also adopt a threaded connection manner, a screw connection manner or a positioning pin connection manner. The stress plate 5 and the stretching base 7 can be in the shape of triangle, rectangle and the like, preferably, the shape of rounded triangle, and the number of the dowel bars 6 is 3, so that the load can be stably transferred, and the inclination of the stretching frame can be prevented. The lower end of the dowel bar 6 is provided with an external thread, and the stretching base 7 is fixed at the lower end of the dowel bar 6 through a second fixing nut 8 so as to be convenient to detach.

The stress plate 5 is positioned above the top plate 3, and the stress plate 5 and the top plate 3 are spaced at a proper distance to ensure that the stress plate 5 can transfer load to the dowel bar 6 after receiving compressive load. Dowel bar 6 is a sliding fit with top plate 3 with the fit clearance as small as possible to ensure that compressive loads are transmitted vertically down dowel bar 6.

The lower spherical head holder 9 and the upper spherical head holder 11 are used for holding a rock sample 12, the lower clamping blind groove and the upper clamping blind groove can fix the sample 12, and the lower clamping blind groove and the upper clamping blind groove can be circular holes or square holes and are determined according to the shape of the sample 12.

Lower part spherical head holder 9 and upper portion spherical head holder 11 all are provided with hemispherical arc surface, are provided with the groove with the cooperation of upper portion spherical head holder 11 arc surface on the roof 3 simultaneously, are provided with the groove with the cooperation of lower part spherical head holder 9 arc surface on the tensile base 7 for lower part spherical head holder 9 and upper portion spherical head holder 11 can rotate in a flexible way in certain angular range. After the sample 12 is processed, it is impossible to completely ensure that the two end faces are perpendicular to the axis of the sample 12, and after the lower clamping blind groove and the upper clamping blind groove are respectively bonded with the upper end face and the lower end face of the sample 12, the axis of the tensile load cannot be completely coincided with the axis of the sample 12, and if a certain included angle exists, the eccentric load is caused, and the test result is influenced. After the lower spherical head holder 9 and the upper spherical head holder 11 are provided with the hemispherical arc surfaces, if the axis of the tensile load is deviated from the axis of the test sample 12 during the test, the lower spherical head holder 9 and the upper spherical head holder 11 can automatically rotate under the action of the load, so that the direction of the load is consistent with the axial direction of the test sample 12, and the accuracy of the test result is ensured.

As shown in fig. 2, the lower spherical head holder 9 and the upper spherical head holder 11 are both limited by the hemispherical arc-shaped surface, and the lower spherical head holder 9 and the upper spherical head holder 11 can be easily taken down before and after the test, so that the end surface of the sample 12 is adhered to the bottoms of the lower clamping blind groove and the upper clamping blind groove, and the operation difficulty is low. In addition, the lower ball head holder 9 and the upper ball head holder 11 for fixing of test pieces 12 of different shapes and sizes can be replaced, so that the present apparatus can be used for tensile tests of test pieces 12 of various shapes and sizes.

Example two

As shown in fig. 3, the utility model discloses a direct tensile test device of rock suitable for all compression testing machines, which comprises a supporting rack, the fixed roof 3 that is provided with in top of support frame, the top of roof 3 is provided with atress board 5, be provided with many vertical dowel steel 6 on the atress board 5, dowel steel 6 vertically run through roof 3 and with roof 3 sliding fit, and the lower extreme of dowel steel 6 is provided with tensile base 7, be provided with on the tensile base 7 with tensile base 7 sliding fit's spherical head holder of lower part 9, the top of spherical head holder of lower part 9 is provided with the blind groove of lower part centre gripping, be provided with on the roof 3 with the spherical head holder 11 of upper part of 3 sliding fit, the bottom of the spherical head holder 11 of upper part is provided with the blind groove of upper part centre gripping, the blind groove of upper part centre gripping is circular port or rectangular hole with the blind groove of lower part centre gripping, the central line in the blind groove of upper part centre gripping coincides with the central line in lower part centre gripping groove. The support frame includes base 1 and the vertical many stands 2 that set up on base 1, and roof 3 is fixed in the upper portion of stand 2 through first fixation nut 4. Base 1 and roof 3 all are fillet triangle-shaped, stand 2 is three. The stress plate 5 and the stretching base 7 are in a shape of a fillet triangle, and the number of the dowel bars 6 is three.

The lower extreme of dowel steel 6 is provided with the horizontally connecting rod, and the lateral wall of tensile base 7 is provided with the embedded groove, and the connecting rod is connected with the embedding hole plug-in connection.

EXAMPLE III

As shown in fig. 4, the utility model discloses a direct tensile test device of rock suitable for all compression testing machines, which comprises a supporting rack, the fixed roof 3 that is provided with in top of support frame, the top of roof 3 is provided with atress board 5, be provided with many vertical dowel steel 6 on the atress board 5, dowel steel 6 vertically run through roof 3 and with roof 3 sliding fit, and the lower extreme of dowel steel 6 is provided with tensile base 7, be provided with on the tensile base 7 with tensile base 7 sliding fit's spherical head holder of lower part 9, the top of spherical head holder of lower part 9 is provided with the blind groove of lower part centre gripping, be provided with on the roof 3 with the spherical head holder 11 of upper part of 3 sliding fit, the bottom of the spherical head holder 11 of upper part is provided with the blind groove of upper part centre gripping, the blind groove of upper part centre gripping is circular port or rectangular hole with the blind groove of lower part centre gripping, the central line in the blind groove of upper part centre gripping coincides with the central line in lower part centre gripping groove. The support frame includes base 1 and the vertical many stands 2 that set up on base 1, and roof 3 is fixed in the upper portion of stand 2 through first fixation nut 4. Base 1 and roof 3 all are fillet triangle-shaped, stand 2 is three. The stress plate 5 and the stretching base 7 are in a shape of a rounded triangle, and the number of the dowel bars 6 is three.

The edge of tensile base 7 is provided with the connection notch, and the lower extreme of dowel steel 6 is provided with and is connected notch complex connecting block, and the connecting block is located the connection notch and can dismantle with tensile base 7 and be connected. The connecting block can be connected with the stretching base 7 through connecting pieces such as bolts.

The testing method of the rock direct tensile testing device suitable for all the compression testing machines can adopt any one of the rock tensile testing devices in the first to the third embodiments, wherein one end of the test sample 12 is bonded to the lower clamping blind groove of the lower spherical head clamping device 9 through strong glue, and the other end of the test sample 12 is bonded to the upper clamping blind groove of the upper spherical head clamping device 11 through strong glue. The cross section of the sample 12 may be circular, or may be various shapes such as rectangular, oval, etc., and the lower ball head holder 9 and the upper ball head holder 11 are prepared according to the shape and size of the sample 12. And then the whole rock tensile test device is placed on a material compression mechanical testing machine, the material compression mechanical testing machine is utilized to apply a compression load to the stress plate 5, the compression load is transmitted to the tensile base 7 through the transmission rod 6, the tensile base 7 forms a tensile load on the test sample 12, and the magnitude of the tensile load is equal to that of the compression load applied by the material compression mechanical testing machine.

The utility model discloses a direct tensile test device of rock suitable for all compression testing machines converts compressive load into tensile load through the tensile frame that atress board 5, dowel bar 6 and tensile base 7 are constituteed, is equal to current direct tensile test's load to the load that sample 12 applyed, can guarantee to take place to destroy along the position that sample bearing capacity is minimum, has overcome the defect that traditional indirect tensile method accuracy is low.

In addition, the material compression mechanical testing machine is conventional testing equipment, the compression mechanical tests of various materials adopt the material compression mechanical testing machine to apply loads, the equipment is simple in structure, low in operation threshold and low in cost, common small and medium-sized enterprises, research institutes and the like can purchase and use the equipment, and the defects that the traditional direct tensile testing equipment is high in cost and high in operation difficulty are overcome.

Additionally, the utility model discloses simple structure, it is with low costs, and compact structure, it is small, can use with the cooperation of conventional various material compression mechanics testing machine, realize the rock tensile test under the multiple condition.

Besides the above test mode, the utility model discloses a rock tensile test under triaxial lateral pressure condition can also be realized to the direct tensile test device of rock suitable for all compression testing machines, can cooperate with current three-axis testing machine, and concrete test process is: one end of the sample 12 is bonded to the lower clamping blind groove of the lower spherical head clamp 9 through strong glue, and the other end of the sample 12 is bonded to the upper clamping blind groove of the upper spherical head clamp 11 through strong glue. And an oil pressure protective heat shrinkage film 10 is fixed to the outer walls of the lower ball head holder 9, the test piece 12, and the upper ball head holder 11, as shown in fig. 2, 3, or 4. And then the whole rock tensile test device is arranged on a base inside a pressure chamber of the triaxial test machine, so that the stress plate 5 of the rock tensile test device can be ensured to be in good contact with a pressure head of the triaxial test machine, and the rock tensile test device is fixed by adopting bolts. The pressure chamber 18 is filled with oil to apply triaxial lateral compressive stress to a target value, a pressure head of a tester applies compressive load to the stress plate 5, the compressive load is transmitted to the tensile base 7 through the transmission rod 6, the tensile base 7 forms tensile load on the test sample 12, and the magnitude of the tensile load is equal to that of the compressive load applied by a material compression mechanics testing machine; when the sample 12 is broken, the oil in the pressure chamber is withdrawn.

Besides the above test modes, the rock tensile test device of the utility model can also carry out two direct tensile tests of rock under the direct compressive stress applied axially, thereby solving the problem that the direct tensile test of rock can not be carried out under the direct compressive stress applied axially; and the operation is simple and convenient, the rock tensile test device of the first, second or third embodiment can be placed into a test bed of a true three-dimensional loading tester to carry out two rock tensile tests under the direct compressive stress applied in the axial direction, the complex disassembly and assembly are not needed, the test can be carried out by only one person, and manpower and material resources are saved.

The conventional true three-way loading testing machine comprises an experiment table, wherein 4 horizontal supporting shafts are arranged around the experiment table, two adjacent supporting shafts are vertical to each other, one end of each supporting shaft, which is far away from the experiment table, is provided with a pressurizing mechanism, and the other end of each supporting shaft is provided with a vertical pressure plate; a pressure head is arranged above the experiment table.

The specific test process is as follows: preparing a test sample 12 with a rectangular cross section, bonding one end of the test sample 12 to the lower clamping blind groove of the lower spherical head clamp 9 through strong glue, and bonding the other end of the test sample 12 to the upper clamping blind groove of the upper spherical head clamp 11 through strong glue. Then the whole rock tensile test device is placed on a test bed of a true three-way loading tester, four sides of the test sample 12 are ensured to correspond to the positions of four pressure plates, namely, each pressure plate can be attached to one side of the test sample 12, then a pressure mechanism is utilized to apply pressure to the supporting shaft, and the pressure is transmitted to the test sample 12 through the pressure plates. And applying a compression load to the stress plate 5 by using a pressure head of the true three-way loading testing machine, transmitting the compression load to a tensile base 7 through a transmission rod 6, forming a tensile load on the test sample 12 by the tensile base 7, and enabling the magnitude of the tensile load to be equal to the compression load applied by the material compression mechanical testing machine. After the sample 12 is broken, the three axial forces of the true three-way loading tester are unloaded, and the sample 12 can be taken out.

To sum up, the utility model discloses reduce equipment cost when guaranteeing the test accuracy, simplified test operation, can realize the rock tensile test under the multiple condition.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. Rock direct tensile test device suitable for all compression testing machines, its characterized in that: the supporting frame is characterized by comprising a supporting frame, the fixed roof (3) that is provided with in top of support frame, the top of roof (3) is provided with atress board (5), be provided with many vertical dowel steel (6) on atress board (5), dowel steel (6) vertically run through roof (3) and with roof (3) sliding fit, just the lower extreme of dowel steel (6) is provided with tensile base (7), be provided with on tensile base (7) with tensile base (7) sliding fit's spherical first holder of lower part (9), the top of spherical first holder of lower part (9) is provided with the blind groove of lower part centre gripping, be provided with on roof (3) with spherical first holder of upper portion (11) sliding fit, the bottom of spherical first holder of upper portion (11) is provided with the blind groove of upper portion centre gripping, the central line in the blind groove of upper portion centre gripping coincides with the central line in the blind groove of lower part centre gripping.

2. The direct rock tensile testing apparatus applicable to all compression testers according to claim 1, wherein: the support frame comprises a base (1) and a plurality of upright columns (2) vertically arranged on the base (1), and a top plate (3) is fixed on the upper portions of the upright columns (2) through first fixing nuts (4).

3. The direct rock tensile testing apparatus for all compression testers, according to claim 2, wherein: the base (1) and the top plate (3) are all in the shape of a rounded triangle, and the number of the stand columns (2) is three.

4. A rock direct tension test apparatus adapted for use in all compression testers as claimed in claim 1, 2 or 3 wherein: the stress plate (5) and the stretching base (7) are in a shape of a rounded triangle, and the number of the dowel bars (6) is three.

5. The direct rock tensile testing apparatus applicable to all compression testers according to claim 1, wherein: the stretching base (7) is fixed at the lower end of the dowel bar (6) through a second fixing nut (8).

6. The direct rock tensile testing apparatus applicable to all compression testers according to claim 1, wherein: the lower extreme of dowel steel (6) is provided with the horizontally connecting rod, the lateral wall of tensile base (7) is provided with the embedding hole, the connecting rod is connected with the embedding hole plug-in connection.

7. The direct rock tensile testing apparatus applicable to all compression testers according to claim 1, wherein: the edge of tensile base (7) is provided with the connection notch, the lower extreme of dowel steel (6) be provided with be connected notch complex connecting block, the connecting block is located the connection notch and can dismantle with tensile base (7) and be connected.

8. The direct rock tensile testing apparatus for all compression testers, according to claim 1, wherein: the upper clamping blind groove and the lower clamping blind groove are circular holes or rectangular holes.