Rock direct tensile test device and test method capable of avoiding eccentric bending moment

Abstract

The invention discloses a rock direct tensile test device capable of avoiding eccentric bending moment, which comprises two clamping pieces which are used for clamping rock and are oppositely arranged up and down, the clamping piece on the upper side is arranged on a supporting assembly through a tensile assembly, and an upper anti-eccentric assembly is arranged between the clamping piece on the upper side and the tensile assembly; the clamping piece on the lower side is arranged on the supporting assembly, a lower anti-eccentric assembly is arranged between the clamping piece on the lower side and the supporting assembly, and meanwhile the invention further discloses a rock direct tensile test method. The whole structure is simple, dismounting and carrying are convenient, the device can be used for outdoor on-site testing, damage to rock samples in the transportation process is reduced, and data accuracy is guaranteed; meanwhile, direct tensile tests of different types of rock tests can be realized by disassembling the clamping piece; anti-eccentric assemblies are arranged at the connecting positions of the upper clamping piece and the lower clamping piece and the other parts, so that eccentric bending moment generated in the direct tensile test process can be effectively eliminated, and the accuracy of test data is further ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of rock mechanics, and in particular relates to a rock direct tensile test device and a test method for avoiding eccentric bending moment. Background Art

[0002] Direct tensile test is one of the key research methods for studying the mechanical properties of rocks. Through direct tensile test, we can fully understand the mechanical response of rocks under tension, including elasticity, plasticity, strength and other characteristics. At present, most rock direct tensile test devices are set up in the laboratory, and the overall volume is large, so that the test can only be carried out in a fixed position, that is, it is limited by the site, and the rock samples taken from the site will also be damaged to varying degrees when transported to the laboratory, making it impossible to accurately measure the rock mechanical parameters in the first time.

[0003] Although some devices are portable and can be used to conduct direct rock tensile tests on site, the generation of eccentric bending moments during the tensile process cannot be avoided. When the tensile load is small, the eccentric bending moment generated is small, but when the tensile load gradually increases, the increasing eccentric bending moment will cause a large deviation in the test results, making it difficult to ensure the accuracy of the data results. Summary of the invention

[0004] The present invention proposes a rock direct tensile test device that avoids eccentric bending moment. While being easy to carry so that the test can be carried out on site, the device can also effectively eliminate the generation of eccentric bending moment, thereby ensuring the test accuracy requirements.

[0005] To this end, the technical solution adopted by the present invention is: a rock direct tensile test device for avoiding eccentric bending moment, including two clamping members for clamping rocks and arranged opposite to each other up and down, the upper clamping member is arranged on the support assembly through the tensile assembly, and an upper anti-eccentric assembly is arranged between the upper clamping member and the tensile assembly, the lower clamping member is arranged on the support assembly, and a lower anti-eccentric assembly is arranged between the lower clamping member and the support assembly.

[0006] As a preferred embodiment of the above scheme, the support assembly includes a base, a limiting top plate is arranged above the base, and at least two columns are arranged between the limiting top plate and the base, the upper ends of the columns are provided with external threads, and each column is provided with a fixing nut for fixing the position of the limiting top plate.

[0007] Further preferably, the stretching assembly includes a stretching top plate and at least two vertically arranged double-headed cylinders, the telescopic rod at the lower end of each double-headed cylinder is arranged on the supporting assembly, and the stretching top plate is arranged on the telescopic rods at the upper ends of all double-headed cylinders.

[0008] Further preferably, the upper anti-eccentricity component and the lower anti-eccentricity component have the same structure and both include connecting parts arranged on corresponding components, at least two first connecting plates are arranged on the connecting parts at intervals, at least two second connecting plates are arranged on the clamping parts at intervals, and the first connecting plates and the second connecting plates are symmetrically arranged up and down, connecting shafts are passed through all the first connecting plates and all the second connecting plates, an anti-eccentricity part is arranged between the two connecting shafts, and an anti-eccentricity part is arranged between any two adjacent first connecting plates.

[0009] Further preferably, the anti-eccentric member includes a first connecting block, a second connecting block and a connecting ring, the connecting ring is arranged between the first connecting block and the second connecting block and is sleeved outside the connecting shaft, the first connecting block and the second connecting block are both horizontally penetrated with a through hole for the connecting shaft to pass through, the through hole on the first connecting block is coaxially arranged on the side close to the second connecting block with a groove for accommodating the connecting ring, and the through hole on the second connecting block is coaxially arranged on the side close to the first connecting block with a protrusion for the connecting ring to be sleeved.

[0010] Further preferably, the connecting shaft on the upper anti-eccentricity component and the connecting shaft on the lower anti-eccentricity component are horizontally arranged perpendicular to each other.

[0011] Further preferably, the connecting member includes a limiting member for connecting with a corresponding component, one end of the limiting member is arranged as a ball head, and the other end of the limiting member is provided with a limiting connecting member for preventing the ball head from being separated from the corresponding component after passing through the corresponding component, and a certain distance is left between the limiting connecting member and the corresponding component when stretched.

[0012] Further preferably, the clamping member is provided with a receiving groove for receiving the rock sample, and a plurality of the clamping members are provided, and the receiving grooves on each pair of clamping members can be set to a shape corresponding to a round, square, or dog-bone-shaped rock sample.

[0013] Also disclosed is a rock direct tensile test method, comprising the following steps:

[0014] S1 installing the rock sample: making a rock sample of corresponding size according to the requirements, and placing the rock sample into the receiving grooves of the two clamping members, and the receiving grooves are coated with an adhesive for fixing the rock sample;

[0015] S2 test device consists of: first assemble the anti-eccentricity piece, then install the clamping piece on the connecting piece through the connecting shaft and the anti-eccentricity piece;

[0016] S3 conducts the test: the double-head cylinder works and starts the direct tensile test of rock. After the rock sample is tensilely damaged, the corresponding data is recorded and the broken rock sample and adhesive on the clamp are cleaned.

[0017] Beneficial effects of the present invention:

[0018] 1) The overall structure is simple and easy to disassemble and carry, so that it can be used for outdoor field testing, reducing the damage of rock samples during transportation and ensuring the accuracy of data; at the same time, direct tensile tests of different types of rock tests can be achieved by disassembling the clamping parts.

[0019] 2) Anti-eccentricity components are provided at the locations where the upper and lower clamps are connected to the remaining components, which can effectively eliminate the eccentric bending moment generated during the direct tensile test and further ensure the accuracy of the test data. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the present invention.

[0021] Figure 2 It is a schematic diagram of the anti-eccentricity member of the present invention (each component includes a front view and a side view).

[0022] Figure 3 for Figure 1 A is an enlarged view of the middle image.

[0023] Figure 4 for Figure 1 Enlarged view of B.

[0024] Figure 5 Schematic diagram of the clamping member of the present invention having receiving grooves of different shapes.

[0025] Figure numerals: base-1, limiting top plate-2, column-3, fixing nut-4, stretching top plate-5, buffer pad-6, limiting piece-7, telescopic rod-8, double-head cylinder-9, oil inlet pipeline-10, limiting connecting piece-11, anti-eccentric piece-12, first connecting block-1201, second connecting block-1202, connecting ring-1203, connecting shaft-13, clamping piece-14, rock sample-15. DETAILED DESCRIPTION

[0026] The present invention will be further described below by way of embodiments and in conjunction with the accompanying drawings:

[0027] like Figure 1-5 As shown, a rock direct tensile test device for avoiding eccentric bending moment is mainly composed of a clamp 14, a tensile assembly, a support assembly, an upper anti-eccentric assembly and a lower anti-eccentric assembly. Among them, the clamp 14 is used to clamp the rock and is arranged opposite to each other up and down. The upper clamp 14 is arranged on the support assembly through the tensile assembly, and an upper anti-eccentric assembly is arranged between the upper clamp 14 and the tensile assembly. The lower clamp 14 is arranged on the support assembly, and a lower anti-eccentric assembly is arranged between the lower clamp and the support assembly.

[0028] The support assembly includes a base 1, a limited top plate 2 is arranged above the base 1, and at least two columns 3 are arranged between the limited top plate 2 and the base 1, preferably four columns are arranged in a rectangular arrangement. An external thread is arranged at the upper end of the column 3, and each column 3 is provided with a fixing nut 4 for fixing the position of the limited top plate 2. Preferably, a circle of protective net is detachably arranged outside the column, and the protective net can also be a transparent protective cover to reduce external interference during the test.

[0029] The stretching assembly includes a stretching top plate 5 and at least two vertically arranged double-headed cylinders 9. The telescopic rod 8 at the lower end of each double-headed cylinder 9 is arranged on the supporting assembly, and the stretching top plate 5 is arranged on the telescopic rods at the upper ends of all double-headed cylinders 9. The double-headed cylinder is located inside the column, and a buffer pad 6 is arranged above the stretching top plate to prevent the stretching top plate from directly pressing against the limit top plate during stretching. It is best that the double-headed cylinder adopts a double-headed oil cylinder. In order to realize the operation of the double-headed cylinder, the double-headed cylinder is equipped with an oil inlet pipeline 10.

[0030] The upper anti-eccentricity component and the lower anti-eccentricity component have the same structure, both of which include connecting parts arranged on corresponding parts, at least two first connecting plates are arranged on the connecting parts at intervals, at least two second connecting plates are arranged on the clamping member 14 at intervals, and the first connecting plates and the second connecting plates are arranged symmetrically up and down, connecting shafts 13 are passed through all the first connecting plates and all the second connecting plates, an anti-eccentricity component 12 is arranged between the two connecting shafts 13, and an anti-eccentricity component 12 is arranged between any two adjacent first connecting plates.

[0031] The anti-eccentric member 12 includes a first connection block 1201, a second connection block 1202 and a connection ring 1203. The first connection block 1201 and the second connection block 1202 are both horizontally provided with through holes for the connection shaft 13 to pass through, and the connection ring 1203 is provided between the first connection block 1201 and the second connection block 1202 and sleeved outside the connection shaft 13. In order to achieve the installation of the connection ring, a groove for accommodating the connection ring 1203 is coaxially provided on the side of the through hole on the first connection block 1201 close to the second connection block 1202, and a protrusion for sleeved by the connection ring 1203 is coaxially provided on the side of the through hole on the second connection block 1202 close to the first connection block 1201, that is, one end of the connection ring is sleeved on the protrusion, and the other end is inserted into the groove. The diameter of the through hole is clearance fit with the connection shaft, and the inner diameter of the connection ring is interference fit with the connection shaft.

[0032] To ensure the overall anti-eccentric bending moment effect, the connecting shaft 13 on the upper anti-eccentric component and the connecting shaft 13 on the lower anti-eccentric component are horizontally and perpendicularly arranged to each other. At the same time, the first connecting plate and the second connecting plate on the upper and lower sides are also horizontally and perpendicularly arranged to each other, that is, the two connecting shafts are horizontally and orthogonally arranged, so that it can prevent the generation of eccentric bending moment from two directions, thereby further eliminating the eccentric bending moment and ensuring the accuracy of the test data.

[0033] In order to facilitate the installation of rock samples, clamps and anti-eccentric parts, the connector includes a limiter 7 for connecting with corresponding parts, and one end of the limiter 7 is set as a ball head. The base and the stretching top plate are both provided with mounting holes for accommodating the ball head, and the mounting hole is provided with a small end on the side facing the clamp so that one end of the limiter will not move out along the mounting hole. At the same time, after the other end of the limiter 7 passes through the corresponding part, a limiter connector 11 is provided to prevent the ball head from detaching from the corresponding part, and a certain distance is left between the limiter connector 11 and the corresponding part during stretching, which serves as the distance for the connection to move up and down when the clamp is installed. Preferably, a threaded section that can be screwed onto the limiter connector is provided at the other end of the limiter, so as to facilitate the installation of the connector on the corresponding part.

[0034] like Figure 1 and 5 As shown, a receiving groove for receiving rock samples is provided on the clamping member 14, and a plurality of clamping members are provided. The receiving grooves on each pair of clamping members can be set to corresponding shapes of rock samples in round, square, dog-bone and other shapes, so that the clamping member can clamp different types of rock samples.

[0035] Based on the above test device, a rock direct tensile test method includes the following steps:

[0036] The first step is to install the rock sample. According to the requirements, a rock sample 15 of corresponding size is made, and the rock sample is placed in the receiving grooves of the two clamps 14, and the receiving grooves are coated with an adhesive for fixing the rock sample 15. The rock sample is made of on-site rocks, and conventional size and small size sample tests can be carried out. Taking the cylindrical rock sample as an example, the diameter can be selected from 10mm, 20mm, 30mm, 40mm, 50mm, etc. The adhesive uses a high-viscosity epoxy resin.

[0037] The second step is to assemble the test device. First, assemble the anti-eccentricity member 12, and then install the clamping member 14 on the connecting member through the connecting shaft 13 and the anti-eccentricity member 12. Specifically, one end of the connecting ring is first sleeved on the protrusion, and the other end is inserted into the groove, and then the anti-eccentricity member is connected to the connecting member and the anti-eccentricity member is connected to the clamping member through two connecting shafts, and the directions of the connecting shafts on the upper and lower sides of the clamping member are perpendicular to each other.

[0038] The third step is to conduct the test. The double-headed cylinder 9 starts the rock direct tensile test, and after the rock sample 15 is tensilely damaged, the corresponding data is recorded, and the broken rock sample and adhesive on the clamping member 14 are cleaned.

Claims

1. A rock direct tensile test device for avoiding eccentric bending moment, comprising two clamping members (14) for clamping rocks and arranged opposite to each other in an upper and lower direction, characterized in that: The upper clamping member (14) is arranged on the supporting member through the stretching member, and an upper anti-eccentricity member is arranged between the upper clamping member (14) and the stretching member, and the lower clamping member (14) is arranged on the supporting member, and a lower anti-eccentricity member is arranged between the lower clamping member and the supporting member.

2. The rock direct tensile test device for avoiding eccentric bending moment according to claim 1, characterized in that: The support assembly comprises a base (1), a limit top plate (2) is arranged above the base (1), and at least two columns (3) are arranged between the limit top plate (2) and the base (1), the upper ends of the columns (3) are provided with external threads, and each column (3) is provided with a fixing nut (4) for fixing the position of the limit top plate (2).

3. The rock direct tensile test device for avoiding eccentric bending moment according to claim 1, characterized in that: The stretching assembly comprises a stretching top plate (5) and at least two vertically arranged double-headed cylinders (9), the telescopic rod (8) at the lower end of each double-headed cylinder (9) being arranged on a supporting assembly, and the stretching top plate (5) being arranged on the telescopic rods at the upper ends of all double-headed cylinders (9).

4. The rock direct tensile test device for avoiding eccentric bending moment according to claim 1, characterized in that: The upper anti-eccentricity component and the lower anti-eccentricity component have the same structure, and both include a connecting member arranged on a corresponding component, at least two first connecting plates are arranged on the connecting member at intervals, at least two second connecting plates are arranged on the clamping member (14) at intervals, and the first connecting plates and the second connecting plates are arranged symmetrically up and down, connecting shafts (13) are passed through all the first connecting plates and all the second connecting plates, an anti-eccentricity component (12) is arranged between the two connecting shafts (13), and an anti-eccentricity component (12) is arranged between any two adjacent first connecting plates.

5. The rock direct tensile test device for avoiding eccentric bending moment according to claim 4, characterized in that: The anti-eccentric member (12) comprises a first connecting block (1201), a second connecting block (1202) and a connecting ring (1203); the connecting ring (1203) is arranged between the first connecting block (1201) and the second connecting block (1202) and is sleeved outside the connecting shaft (13); the first connecting block (1201) and the second connecting block (1202) are both horizontally penetrated with a through hole for the connecting shaft (13) to pass through; a groove for accommodating the connecting ring (1203) is coaxially arranged on a side of the through hole on the first connecting block (1201) close to the second connecting block (1202); a protrusion for sleeved by the connecting ring (1203) is coaxially arranged on a side of the through hole on the second connecting block (1202) close to the first connecting block (1201).

6. The rock direct tensile test device for avoiding eccentric bending moment according to claim 4, characterized in that: The connecting shaft (13) on the upper anti-eccentricity component and the connecting shaft (13) on the lower anti-eccentricity component are arranged horizontally and perpendicularly to each other.

7. The rock direct tensile test device for avoiding eccentric bending moment according to claim 4, characterized in that: The connecting member comprises a limiting member (7) for connecting with a corresponding component, one end of the limiting member (7) is arranged as a ball head, and the other end of the limiting member (7) is provided with a limiting connecting member (11) for preventing the ball head from being separated from the corresponding component after passing through the corresponding component, and a certain distance is left between the limiting connecting member (11) and the corresponding component when stretched.

8. The rock direct tensile test device for avoiding eccentric bending moment according to claim 1, characterized in that: The clamping piece (14) is provided with a receiving groove for receiving the rock sample, and a plurality of the clamping pieces are provided, and the receiving grooves on each pair of clamping pieces can be arranged to correspond to the shapes of the round, square, or dog-bone-shaped rock samples.

9. A rock direct tensile test method, characterized in that: The following steps are involved: S1 installing the rock sample: making a rock sample (15) of a corresponding size according to requirements, and placing the rock sample into the receiving grooves of the two clamping members (14) respectively, wherein the receiving grooves are coated with an adhesive for fixing the rock sample (15); The S2 test device comprises: first assembling the anti-eccentricity member (12), and then installing the clamping member (14) on the connecting member through the connecting shaft (13) and the anti-eccentricity member (12); S3: Conduct the test: The double-head cylinder (9) starts to work and starts the rock direct tensile test. After the rock sample (15) is tensilely damaged, the corresponding data is recorded and the broken rock sample and adhesive on the clamping member (14) are cleaned.

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