A triaxial loading test device for rock mechanics in mining

Abstract

This utility model discloses a triaxial loading test device for rock mechanics in mining, belonging to the technical field of rock mechanics testing equipment. It includes a pressure chamber cylinder, a base, and an axial loading mechanism. The lower outer wall of the cylinder has a conical ring with a downward-facing lower conical surface and an upward-facing upper conical surface. The upper surface of the base has an inwardly recessed conical hole adapted to the lower conical surface and a sealing ring is placed there. The outer side of the base has a shoulder with a downward-facing second conical surface. It also includes a split clamp, the inner wall of which has an upper ring groove and a lower ring groove. The upper wall of the upper ring groove forms an upper wedge surface that fits against the upper conical surface, and the lower wall of the lower ring groove forms a lower wedge surface that fits against the second conical surface. The split clamp is locked by detachable fasteners, so that the upper wedge surface mates with the upper conical surface, and the lower wedge surface mates with the second conical surface, jointly forcing the cylinder and base to axially compress and compress the sealing ring to achieve a self-tightening seal. This device utilizes the wedge surface to convert confining pressure into additional sealing force; the higher the confining pressure, the more reliable the seal.

Description

Technical Field

[0001] This utility model relates to the technical field of rock mechanics testing equipment, specifically a triaxial loading test device for rock mechanics in mining. Background Technology

[0002] In triaxial loading tests of rocks, the pressure chamber cylinder and the base need to form a sealed cavity to contain the rock sample and apply high pressure. Currently, existing triaxial loading test devices generally use flange bolts to connect the cylinder and the base. The lower end face of the cylinder and the upper surface of the base are both horizontal planes. A sealing ring is placed between them, and the two horizontal planes are tightened and flattened by the axial tension of the bolts to achieve a seal.

[0003] This connection method has a key drawback: the seal relies entirely on the initial preload of the bolts, and the horizontal surface fit itself has no self-tightening capability. When the test confining pressure increases, the internal high pressure will generate an upward axial thrust on the cylinder. This thrust directly offsets the bolt preload, causing the clamping force between the sealing surfaces to continuously decrease as the confining pressure increases, which can easily lead to leakage. To address this, this invention proposes a triaxial loading test device for mining rock mechanics. Utility Model Content

[0004] The purpose of this invention is to provide a triaxial loading test device for rock mechanics in mining, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a triaxial loading test device for mining rock mechanics, comprising a pressure chamber cylinder, a base, and an axial loading mechanism, wherein a sealed cavity for accommodating a rock sample is formed between the pressure chamber cylinder and the base; a conical ring protruding outward is provided on the lower outer wall of the pressure chamber cylinder, the conical ring having a lower conical surface facing downward and an upper conical surface facing upward; a concave conical hole adapted to the lower conical surface of the conical ring is provided on the upper surface of the base, and a sealing ring is placed in the concave conical hole; a ring is provided on the outer side of the base. The device includes an outwardly extending shoulder with a downward-facing limiting cone surface; it also includes a split clamp with an upper and lower annular groove on its inner wall. The upper wall of the upper annular groove forms an upper wedge surface that fits against the upper cone surface of the conical ring, and the lower wall of the lower annular groove forms a lower wedge surface that fits against the limiting cone surface. The split clamp is locked by a detachable fastener. When the fastener is locked, the engagement of the upper wedge surface with the upper cone surface and the engagement of the lower wedge surface with the limiting cone surface together force the pressure chamber cylinder and the base to press against each other axially, thereby compressing the sealing ring to achieve a self-tightening seal.

[0006] In an optional implementation,

[0007] The split clamp consists of two semi-circular clamps joined together, and detachable fasteners are used to connect the two semi-circular clamps into one unit.

[0008] In an optional implementation,

[0009] The fasteners are multiple bolts arranged circumferentially.

[0010] In an optional implementation,

[0011] Each semi-circular clamp has connecting lugs at both ends. Bolts are passed through the mounting holes of the corresponding lugs on the two split clamps for locking.

[0012] In an optional implementation,

[0013] The semi-circular clamp has a gap between the connecting lugs, and the axial self-tightening force applied by the upper and lower wedge surfaces can be adjusted by changing the tightness of the bolts.

[0014] In an optional implementation,

[0015] The inclination angle of the upper wedge surface is the same as that of the upper cone surface; the inclination angle of the lower wedge surface is the same as that of the limiting cone surface.

[0016] In an optional implementation,

[0017] The sealing ring is an O-ring.

[0018] In an optional implementation,

[0019] The bottom of the concave conical hole is provided with a rectangular annular groove for limiting the installation of the O-ring seal.

[0020] In an optional implementation,

[0021] The bottom surface of the concave conical hole, located inside the rectangular annular groove, is provided with an upward-protruding annular boss; when the cylinder is pressed, the top surface of the annular boss abuts against the lower end face of the cylinder.

[0022] In an optional implementation,

[0023] The split clamp is a one-piece forged structure, and the surfaces of the upper and lower wedges are hardened by quenching.

[0024] Compared with the prior art, the beneficial effects of this utility model are:

[0025] This invention utilizes the coordinated cooperation between the conical ring of the cylinder, the concave conical hole in the base, and the split clamp wedge surface to convert the axial thrust of the confining pressure applied to the cylinder into an additional clamping force on the sealing surface. This achieves a self-tightening seal where the higher the confining pressure, the greater the sealing force. It eliminates the leakage hazard caused by the pre-tightening force being offset by the confining pressure in traditional flange bolt connections, and improves the sealing reliability of high-pressure tests.

[0026] The split clamp, combined with the upper and lower wedges, synchronously presses the cylinder and the base together. Only a few fasteners on the split clamp need to be tightened to complete the sealing connection, which replaces the dense flange bolts in the traditional structure. The loading and unloading process is greatly simplified, effectively shortening the test preparation time and improving the test operation efficiency.

[0027] The tapered ring and the concave tapered hole can automatically guide and center the seal during assembly, ensuring uniform circumferential compression and avoiding the risk of local leakage caused by off-center loading. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0029] Figure 2 This is a schematic diagram of the pressure chamber cylinder of this utility model;

[0030] Figure 3 This is a schematic diagram of the structure of the split clamp during installation of this utility model;

[0031] Figure 4 This is a cross-sectional view of the pressure chamber cylinder and base after assembly.

[0032] Figure 5 This is a schematic diagram of the pressure chamber cylinder and the base of this utility model in a separated state;

[0033] Figure 6 for Figure 5 Enlarged view of point A in the middle;

[0034] Figure 7 This is a schematic diagram of the cross-section of the semi-circular clamp of this utility model.

[0035] In the diagram: 1. Pressure chamber cylinder; 2. Base; 3. Axial loading mechanism; 4. Sealed cavity; 5. Conical ring; 6. Lower conical surface; 7. Upper conical surface; 8. Concave conical hole; 9. Shoulder; 10. Limiting conical surface; 11. Split clamp; 12. Upper wedge surface; 13. Upper ring groove; 14. Lower ring groove; 15. Lower wedge surface; 16. Fastener; 17. Sealing ring; 18. Semi-circular clamp; 19. Connecting lug; 20. Gap; 21. Rectangular ring groove; 22. Annular boss. Detailed Implementation

[0036] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0037] Example 1: Please refer to Figures 1-7 The diagram shows a triaxial loading test apparatus for mining rock mechanics, comprising a pressure chamber cylinder 1, a base 2, and an axial loading mechanism 3. A sealed cavity 4 for accommodating a rock sample is formed between the pressure chamber cylinder 1 and the base 2. A conical ring 5 protruding outward is provided on the lower outer wall of the pressure chamber cylinder 1. The conical ring 5 has a lower conical surface 6 facing downward and an upper conical surface 7 facing upward. A concave conical hole 8 adapted to the lower conical surface 6 is provided on the upper surface of the base 2, and a sealing ring 17 is placed in the concave conical hole 8. A shoulder 9 extending outward is provided on the outer side of the base 2, and the shoulder 9 has a lower limiting conical surface 10. The device also includes a split clamp 11, the inner wall of which is provided with an upper annular groove 13 and a lower annular groove 14. The upper groove wall of the upper annular groove 13 forms an upper wedge surface 12 that fits against the upper conical surface 7, and the lower groove wall of the lower annular groove 14 forms a lower wedge surface 15 that fits against the limiting conical surface 10. The split clamp 11 is locked by a detachable fastener 16. When the fastener 16 is locked, the engagement of the upper wedge surface 12 with the upper conical surface 7 and the engagement of the lower wedge surface 15 with the limiting conical surface 10 together force the pressure chamber cylinder 1 and the base 2 to press against each other axially, thereby compressing the sealing ring 17 to achieve a self-tightening seal.

[0038] It should be noted that during operation, the rock sample is placed in the sealed cavity 4 between the pressure chamber cylinder 1 and the base 2. Then, the split clamp 11 is installed around the conical ring 5 of the cylinder and the shoulder 9 of the base 2. The upper wedge surface 12 and the upper conical surface 7 are brought into contact by the locking fastener 16, creating a wedging effect. Simultaneously, the lower wedge surface 15 and the limiting conical surface 10 are brought into contact, creating a wedging effect. The two sets of wedge surfaces work together to convert the radial tightening force of the split clamp 11 into a relative axial compressive force, simultaneously pressing the cylinder and base 2 together from both above and below. The sealing ring 17 is axially compressed within the concave conical hole 8, forming a reliable seal. When the internal confining pressure increases, the upward thrust of the confining pressure on the cylinder further tightens the lower conical surface 6 and the concave conical hole 8. The compressive force on the sealing ring 17 not only does not decrease but increases with the increase of the confining pressure, exhibiting self-tightening characteristics.

[0039] In this design, the split clamp 11 is composed of two semi-circular clamps 18 joined together, and a detachable fastener 16 is used to connect the two semi-circular clamps 18 into one unit. The fastener 16 uses multiple bolts arranged circumferentially. Each semi-circular clamp 18 has connecting lugs 19 at both ends, and the bolts pass through the mounting holes of the corresponding lugs of the two split clamps 11 for locking.

[0040] It should be noted that the two-piece split clamp 11 structure eliminates the need to insert the split clamp 11 from the end of the cylinder during installation. It can be directly installed from both sides after the cylinder and base 2 are joined, making the operation convenient. A gap 20 is left between the connecting lugs 19. By changing the tightness of the bolts, the axial self-tightening force applied by the upper wedge surface 12 and the lower wedge surface 15 can be adjusted to meet the sealing force requirements of different test confining pressure levels.

[0041] In this design, the inclination angle of the upper wedge surface 12 is the same as that of the upper conical surface 7, and the inclination angle of the lower wedge surface 15 is the same as that of the limiting conical surface 10. This arrangement ensures that the wedge surfaces are in surface contact, resulting in uniform force distribution and preventing localized stress concentration caused by angular deviations. It also ensures that the axial force is stable and controllable.

[0042] In this design, the sealing ring 17 is an O-ring, and the bottom of the concave conical hole 8 is provided with a rectangular annular groove 21 for limiting the installation of the O-ring. The rectangular annular groove 21 plays a role in positioning and limiting the sealing ring 17, preventing the sealing ring 17 from shifting or falling out during assembly, and ensuring that the sealing ring 17 is in the preset compressed position after each assembly.

[0043] It should be noted that a ring-shaped boss 22 with an upward protrusion is also provided on the bottom surface of the concave conical hole 8, inside the rectangular annular groove 21. When the cylinder is compressed, the top surface of the ring-shaped boss 22 abuts against the lower end face of the cylinder. This ring-shaped boss 22 serves two purposes: firstly, it provides axial restraint to prevent the sealing ring 17 from being over-compressed and damaged; secondly, it provides metal-to-metal auxiliary sealing when the sealing ring 17 fails, further improving the sealing safety of the device.

[0044] In this design, the split clamp 11 is a one-piece forged structure, and the surfaces of the upper wedge surface 12 and the lower wedge surface 15 are hardened by quenching. The one-piece forging eliminates the internal defects that may exist in welded or assembled structures, while the quenching and hardening treatment significantly improves the surface hardness and wear resistance of the wedge surface, enabling it to maintain stable wedge tightness accuracy under long-term repeated disassembly and high-pressure loading conditions, and making it less prone to plastic deformation or wear.

[0045] Example 2:

[0046] refer to Figure 3 and Figure 5 This embodiment, based on Embodiment 1, further optimizes the fit between the connecting lugs 19 of the split clamp 11 and the bolts. The two ends of the semi-circular clamp 18 are respectively provided with connecting lugs 19, each with a mounting hole. The bolt passes through the mounting holes of the corresponding lugs of the two split clamps 11 and is tightened with a nut. A preset gap 20 is left between the two opposing connecting lugs 19 of the two split clamps 11, providing displacement space for further tightening of the bolts.

[0047] It should be noted that during assembly, the two semi-circular clamps 18 are first aligned with the outer periphery of the conical ring 5 of the cylinder and the shoulder 9 of the base 2, so that the upper wedge surface 12 is aligned with the upper conical surface 7 and the lower wedge surface 15 is aligned with the limiting conical surface 10. Then, the bolts are inserted and gradually tightened. As the bolts are tightened, the two split clamps 11 gradually close, and the upper wedge surface 12 along the upper conical surface 7 and the lower wedge surface 15 along the limiting conical surface 10 generate a wedging displacement, forcing the cylinder to move downward and the base 2 upward relative to each other, and the sealing ring 17 is axially compressed. By controlling the pre-tightening torque of the bolts, the magnitude of the axial self-tightening force can be precisely adjusted to adapt to different confining pressure test conditions. When disassembly is required after the test, the two split clamps 11 can be separated and removed simply by loosening the bolts, without having to lift the cylinder from the base 2, greatly improving the disassembly and assembly efficiency.

[0048] In this design, the annular boss 22 on the bottom surface of the concave conical hole 8 contacts the lower end face of the cylinder when the sealing ring 17 is compressed to a preset degree. When the bolt is tightened to the specified torque, the annular boss 22 forms rigid contact with the lower end face of the cylinder. At this time, the sealing ring 17 is exactly at the designed compression amount. The operator can visually judge whether the assembly is in place by observing the contact state between the annular boss 22 and the cylinder, thus avoiding the problems of over-tightening causing damage to the sealing ring 17 or under-tightening causing sealing failure.

[0049] It should be noted that the annular boss 22 is located at the bottom of the concave conical hole 8 and inside the sealing ring 17. Although its contact state with the lower end face of the cylinder cannot be directly observed after assembly, the intuitive judgment in this invention does not rely on visual observation of the internal contact surface itself, but is indirectly achieved through the accompanying state changes during the assembly process. Specifically, when the bolt is tightened to the moment when the top surface of the annular boss 22 rigidly abuts against the lower end face of the cylinder, the displacement resistance of the wedge fit will suddenly increase, manifested as a sharp increase in bolt torque or no change in the closing gap 20 of the split clamp 11. The operator can clearly and instantly perceive that the annular boss 22 has made contact with the end face of the cylinder by the sudden change in the torque wrench reading or the disappearance of the gap 20 between the connecting lugs 19, thus achieving the so-called intuitive judgment. This method does not require opening observation holes on the split clamp 11 or the cylinder, nor does it require additional detection tools. The judgment can be completed solely by the mechanical feedback and displacement changes during conventional assembly operations, ensuring that the compression of the sealing ring 17 is accurate and controllable.

[0050] It should be noted that in the above embodiments, the lower conical surface 6 of the conical ring 5 and the concave conical hole 8 of the base 2 also play an automatic centering role during the assembly process. When the cylinder is placed on the base 2, the conical surface fit can guide the cylinder to automatically center, ensuring that the compression of the sealing ring 17 is uniform in all directions, effectively avoiding the risk of local leakage caused by off-center load.

[0051] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0052] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A triaxial loading test device for rock mechanics in mining, comprising a pressure chamber cylinder (1), a base (2) and an axial loading mechanism (3), wherein a closed cavity (4) for accommodating a rock sample is formed between the pressure chamber cylinder (1) and the base (2). Its features are: The lower outer wall of the pressure chamber cylinder (1) is provided with a conical ring (5) that protrudes outward. The conical ring (5) has a lower conical surface (6) facing downward and an upper conical surface (7) facing upward. The upper surface of the base (2) is provided with a concave conical hole (8) that is compatible with the lower conical surface (6) of the conical ring (5), and a sealing ring (17) is placed in the concave conical hole (8). The outer side of the base (2) is provided with a ring of outwardly extending shoulder (9), and the shoulder (9) has a downward-facing limiting cone surface (10). It also includes a split clamp (11), the inner wall of which is provided with an upper ring groove (13) and a lower ring groove (14). The upper wall of the upper ring groove (13) forms an upper wedge surface (12) that fits against the upper cone surface (7) of the conical ring (5), and the lower wall of the lower ring groove (14) forms a lower wedge surface (15) that fits against the limiting cone surface (10). The split clamp (11) is locked by a detachable fastener (16). When the fastener (16) is locked, the cooperation between the upper wedge surface (12) and the upper cone surface (7), and the cooperation between the lower wedge surface (15) and the limiting cone surface (10), together force the pressure chamber cylinder (1) and the base (2) to press against each other axially, so as to compress the sealing ring (17) to achieve self-tightening sealing.

2. The mine rock mechanics triaxial loading test device according to claim 1, characterized in that: The split clamp (11) is composed of two semi-circular clamps (18) joined together, and the detachable fastener (16) is used to connect the two semi-circular clamps (18) into one piece.

3. The mine rock mechanics triaxial loading test device according to claim 2, characterized in that: The fastener (16) is a plurality of bolts arranged circumferentially.

4. The mine rock mechanics triaxial loading test device according to claim 3, characterized in that: Each of the semi-circular clamps (18) has connecting lugs (19) at both ends, and the bolts are locked by passing through the mounting holes of the corresponding lugs of the two split clamps (11).

5. The mine rock mechanics triaxial loading test device according to claim 4, characterized in that: The semi-circular clamp (18) has a gap (20) between the connecting lugs (19), and the axial self-tightening force applied by the upper wedge surface (12) and the lower wedge surface (15) can be adjusted by changing the tightness of the bolt.

6. The mine rock mechanics triaxial loading test device according to claim 1, characterized in that: The inclination angle of the upper wedge surface (12) is the same as that of the upper cone surface (7); the inclination angle of the lower wedge surface (15) is the same as that of the limiting cone surface (10).

7. The mine rock mechanics triaxial loading test device according to claim 1, characterized in that: The sealing ring (17) is an O-ring.

8. The mine rock mechanics triaxial loading test device according to claim 7, characterized in that: The bottom of the concave conical hole (8) is provided with a rectangular annular groove (21) for limiting the installation of the O-ring seal.

9. The mine rock mechanics triaxial loading test device according to claim 8, characterized in that: The bottom surface of the concave conical hole (8), located inside the rectangular annular groove (21), is provided with an annular boss (22) that protrudes upward; when the cylinder is pressed, the top surface of the annular boss (22) abuts against the lower end surface of the cylinder. 10.The mine rock mechanics triaxial loading test device according to claim 1, characterized in that: The split clamp (11) is an integral forging structure, and the surfaces of the upper wedge (12) and the lower wedge (15) are hardened by quenching.

Images