Testing device and method for simulating fracture of mine earthquake source

Abstract

The invention discloses a test device and method for simulating fracture of a mine earthquake source. The method comprises the following steps: putting a rock sample into the test device and mounting the test device to a triaxial testing machine; a loading method is determined according to the fracture type of the mine earthquake source needing to be simulated, a triaxial testing machine is used for applying load, and if pressure or tension needs to be applied to the rock sample, the tension or pressure is applied to the inner frame to drive the upper clamping part and the lower clamping part to apply required stress to the rock sample; when shear force needs to be applied to the rock sample, pressure is applied to the two shear stress loading parts at the same time, then the lower clamping part is driven to move along the horizontal sliding groove relative to the upper clamping part, the needed shear force is applied to the rock sample, and a compression-shear composite fracture or tension-shear composite fracture test is achieved. The fracture processes of different mine earthquake sources are effectively simulated, so that the acoustic emission data corresponding to the fracture processes of the different mine earthquake sources are obtained, and data support is provided for revealing fracture evolution mechanisms of the different earthquake sources and disaster source early warning.

Description

Technical Field

[0001] The present invention relates to the technical field of mine dynamic disaster simulation, and in particular to a test device and method for simulating mine earthquake source rupture. Background Art

[0002] Frequent mining earthquakes pose a serious threat to coal mine safety and production in deep mines. Limited on-site observation conditions prevent a clear understanding of the damage characteristics of the earthquake source, making it difficult to fully understand the evolutionary mechanisms of mine earthquake ruptures and to fully grasp the precursors of source damage and instability. Therefore, simulating the rupture process of mine earthquake sources and understanding the dynamics and evolution of ruptures at different sources are crucial for understanding the evolutionary mechanisms of source ruptures and providing early warning of disaster sources.

[0003] At present, acoustic emission technology has been widely used in laboratory rock failure experiments as an effective means of monitoring rock fracture processes. It captures the elastic wave signals released by the expansion of microcracks inside the rock to achieve fracture location and mechanism inversion. The types of damage caused by coal mine earthquake sources are mainly compression shear fracture and shear fracture. The research on the compression shear fracture mechanism of rock specimens has been relatively in-depth. The currently widely used triaxial compression test device can effectively simulate the compression shear fracture process by applying axial pressure and confining pressure. Its fixture structure is simple and the loading path is clear. However, in the complex stress environment induced by deep mining, tensile shear fracture also occurs frequently and is highly destructive. However, existing technologies lack standardized tensile shear testing capabilities. Traditional compression shear fixtures cannot apply axial tension in reverse. This technical imbalance makes it difficult to accurately obtain the fracture evolution law and warning threshold of tensile shear type mine earthquakes through experiments, which restricts the improvement of the coal mine dynamic disaster prevention and control system.

[0004] There are some fixture devices for rock tension and shear testing in the prior art, such as the invention with publication number CN115753441A, entitled: Rock tension and shear combination test device suitable for compression and shear testing machine and method of use. This device can perform tension and shear combination load tests on rocks, but these devices mainly solve general rock mechanics testing problems, that is, testing the mechanical parameters of rock samples. Their design goal is not to simulate the fracture process of mine earthquake sources. Since they do not consider the integrated optimization with the acoustic emission system to invert the source parameters, nor do they solve the loading simulation requirements of specific fracture types in deep mine earthquake environments, the above-mentioned devices cannot be directly applied to the test process of simulating mine earthquake source fractures.

[0005] Therefore, how to provide a new test device that can effectively simulate the rupture process of different mining earthquake sources by applying compressive shear or tensile shear loads to rock samples according to the rupture types of different mining earthquake sources, thereby obtaining the required data and providing data support for revealing the rupture evolution mechanism of different earthquake sources and disaster source early warning, is the research direction required by the present invention. Summary of the Invention

[0006] In view of the problems existing in the above-mentioned prior art, the present invention provides a test device and method for simulating the rupture of the earthquake source, which can effectively solve the above-mentioned technical problems.

[0007] In order to achieve the above-mentioned object, the technical solution adopted by the present invention is: a test device for simulating the fracture of a mine earthquake source, comprising an outer frame, an inner frame, an upper clamping component, a lower clamping component, a sliding base and two shear stress loading components;

[0008] The outer frame is provided with a slide groove, the inner frame is mounted on the outer frame, and both sides of the inner frame are in the slide groove, so that the inner frame slides up and down relative to the outer frame along the slide groove;

[0009] The sliding base is fixed to the inner frame, and a horizontal sliding groove is provided at the upper end of the sliding base. The lower portion of the lower clamping member is mounted in the horizontal sliding groove and can move relative to the sliding base along the horizontal sliding groove. The upper clamping member is mounted on the outer frame, and the upper clamping member and the lower clamping member are arranged relative to each other to form a sample placement space therebetween for placing the rock sample.

[0010] The two shear stress loading components are respectively located on both sides of the sample placement space, one end of one shear stress loading component passes through the outer frame and the inner frame and contacts the side of the upper clamping component, and one end of the other shear stress loading component passes through the outer frame and the inner frame and contacts the side of the lower clamping component; when pressure or tension is applied to the rock sample, the upper clamping component and the lower clamping component are driven to apply the required stress to the rock sample by applying tension or pressure to the inner frame; when shear force is applied to the rock sample, pressure is applied to the two shear stress loading components at the same time, thereby driving the lower clamping component to move relative to the upper clamping component along the horizontal sliding groove, thereby applying the required shear force to the rock sample.

[0011] Furthermore, the outer frame comprises two rectangular frames, which are mirror-symmetrical and connected by bolts; the two rectangular frames have symmetrical grooves on both sides for mounting the inner frame. This structure can further improve the stability during test loading.

[0012] Furthermore, the inner frame is a rectangular parallelepiped frame. The rectangular parallelepiped shape can improve the stability when tension or pressure is applied to the rock sample.

[0013] Furthermore, the upper clamping member and the lower clamping member are both U-shaped members. With this structure, when the two U-shaped members are arranged relative to each other, a sample placement space is formed therein, thereby ensuring the stability of the rock sample after loading.

[0014] Furthermore, the upper clamping member and outer frame, as well as the sliding base and inner frame, are both securely connected by bolts. The sliding base's horizontal sliding groove is a T-shaped groove, and the lower portion of the lower clamping member is provided with a downwardly protruding T-shaped guide rail, which is mounted within the T-shaped groove and allows the lower clamping member to slide horizontally relative to the sliding base. The bolted connection facilitates installation and disassembly of the entire device. Furthermore, the interaction between the T-shaped guide rail and the T-shaped groove ensures that the lower clamping member slides relative to the upper clamping member when shear force is applied, thereby improving the stability of shear force loading.

[0015] Furthermore, the shear stress loading component is a T-shaped loading component, and strip-shaped through-holes are provided on both sides of the outer frame and the inner frame along the direction of the slideway, allowing the shear stress loading component to pass through the outer frame and the inner frame. The provision of the strip-shaped through-holes ensures that the shear stress applied by the shear stress loading component to the rock sample is not affected within a certain range of relative sliding distance between the inner frame and the outer frame.

[0016] The working method of the above-mentioned simulated mining earthquake source rupture test device includes the following steps:

[0017] S1. Prepare rock samples;

[0018] S2. Fixing the acoustic emission probes of the acoustic emission acquisition system on both sides of the rock sample to collect the acoustic emission signals during the rock fracture process in real time;

[0019] S3. placing the assembled test apparatus in a triaxial testing machine, so that the triaxial testing machine can apply tension or compression to the inner frame and apply compression to the two shear stress loading components;

[0020] S4. Fix the rock sample in the sample placement space;

[0021] S5. Determine the loading method based on the type of mining earthquake source rupture to be simulated, apply the load using a triaxial testing machine, and continue loading until the rock sample fails, obtaining acoustic emission data corresponding to different mining earthquake source rupture processes.

[0022] Furthermore, step S5 determines the loading method according to the type of mine earthquake source rupture to be simulated, specifically: if the target mine earthquake source rupture type is compression-shear composite rupture, the triaxial testing machine is controlled to apply tension to the inner frame and pressure to the two shear stress loading components at the same time, so as to realize compressive stress and shear stress loading on the rock sample; if the target mine earthquake source rupture type is tension-shear composite rupture, the triaxial testing machine is controlled to apply pressure to the inner frame and pressure to the two shear stress loading components at the same time, so as to realize tensile stress and shear stress loading on the rock sample; the source rupture type is divided into five rupture forms according to the different proportions of the isotropic component (ISO) and the double-couple component (DC) in the source moment tensor, namely pure tension, tension-shear, pure shear, compression-shear and pure compression. Among them, the mine earthquake in the mine overburden environment is dominated by compression-shear composite rupture and tension-shear composite rupture. The present invention designs loading methods for these two types of rupture types.

[0023] Furthermore, when tensile stress needs to be applied to the rock sample, the upper and lower ends of the rock sample are first bonded and fixed to the upper clamping component and the lower clamping component respectively by adhesive, and then a tensile test is applied to the rock sample.

[0024] Compared with the prior art, the present invention adopts a combination of an outer frame, an inner frame, an upper clamping component, a lower clamping component, a sliding base and two shear stress loading components. When pressure or tension is applied to the rock sample, the upper clamping component and the lower clamping component are driven to apply the required stress to the rock sample by applying tension or pressure to the inner frame; when shear force is applied to the rock sample, pressure is applied to the two shear stress loading components at the same time, thereby driving the lower clamping component to move along the horizontal sliding groove relative to the upper clamping component, thereby applying the required shear force to the rock sample; when conducting the test, the present invention places the rock sample into the test device and installs it to the triaxial testing machine; the loading method is determined according to the type of mine earthquake source rupture to be simulated, and the load is applied using the triaxial testing machine to realize compression-shear composite rupture or tension-shear composite rupture test, effectively simulating the rupture process of different mine earthquake sources, thereby obtaining acoustic emission data corresponding to the rupture process of different mine earthquake sources, and providing data support for revealing the rupture evolution mechanism of different sources and disaster source warning. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 1 is a schematic diagram of the overall structure of an embodiment of the present invention;

[0026] Figure 2 is a perspective schematic diagram of an embodiment of the present invention;

[0027] Figure 3 It is a schematic diagram of the force mode and source rupture type of the mine earthquake source in the embodiment of the present invention.

[0028] In the figure: 1. Outer frame; 2. Inner frame; 3. Shear stress loading component; 4. Upper clamping component; 5. Lower clamping component; 6. Sliding base; 7. Rock sample. DETAILED DESCRIPTION

[0029] The present invention will be further described below.

[0030] like Figure 1 and 2 As shown, a test device for simulating earthquake source rupture includes an outer frame 1, an inner frame 2, an upper clamping component 4, a lower clamping component 5, a sliding base 6, and two shear stress loading components 3. The outer frame 1 is provided with a slide groove, and the inner frame 2 is mounted on the outer frame, with both sides of the inner frame 2 located in the slide groove, so that the inner frame 2 slides up and down along the slide groove relative to the outer frame. The outer frame 2 includes two rectangular frames, which are mirror-symmetrical and connected by bolts. This structure can further improve stability during test loading. The inner frame 2 is a rectangular frame. The rectangular shape can improve stability when tension or pressure is applied to the rock sample 7.

[0031] The sliding base 6 is fixed to the inner frame 2. A horizontal sliding groove is defined at the upper end of the sliding base 6. The lower portion of the lower clamping member 5 is mounted within the horizontal sliding groove and can move along the horizontal sliding groove relative to the sliding base 6. The upper clamping member 4 is mounted on the outer frame. The upper clamping member 4 and the lower clamping member 5 are positioned relative to each other, forming a sample placement space therebetween for placing the rock sample 7. Both the upper clamping member 4 and the lower clamping member 5 are U-shaped members. This structure creates a sample placement space within the two U-shaped members when they are positioned relative to each other, ensuring stability during loading after the rock sample is placed.

[0032] The two shear stress loading components 3 are respectively located on both sides of the sample placement space, one end of one shear stress loading component 3 passes through the outer frame 1 and the inner frame 2 and contacts the side of the upper clamping component 4, and the other end of the shear stress loading component 3 passes through the outer frame 1 and the inner frame 2 and contacts the side of the lower clamping component 5; when pressure or tension is applied to the rock sample 7, the upper clamping component 4 and the lower clamping component 5 are driven to apply the required stress to the rock sample by applying tension or pressure to the inner frame 2; when shear force is applied to the rock sample, pressure is applied to the two shear stress loading components 3 at the same time, thereby driving the lower clamping component 5 to move along the horizontal sliding groove relative to the upper clamping component 4, thereby applying the required shear force to the rock sample 7.

[0033] As an improvement to the present invention, the upper clamping member 4 and the outer frame 1, as well as the sliding base 6 and the inner frame 2, are fixedly connected by bolts. The horizontal sliding groove of the sliding base 6 is a T-shaped sliding groove, and the lower portion of the lower clamping member 5 is provided with a downwardly protruding T-shaped guide rail, which is mounted within the T-shaped sliding groove and is used to enable the lower clamping member 5 to slide horizontally relative to the sliding base 6. The use of bolted connections facilitates installation and disassembly of the entire device. The interaction between the T-shaped guide rail and the T-shaped sliding groove ensures that the lower clamping member 5 slides relative to the upper clamping member 4 when shear force is applied, thereby improving the stability of the shear force application.

[0034] As another improvement to the present invention, the shear stress loading component 3 is a T-shaped loading component, and strip-shaped through-holes are provided on both sides of the outer frame 1 and the inner frame 2 along the direction of the slide groove, allowing the shear stress loading component 3 to pass through the outer frame 1 and the inner frame 2. The provision of the strip-shaped through-holes ensures that the shear stress applied by the shear stress loading component 3 to the rock specimen 7 will not be affected within a certain range of relative sliding distance between the inner frame 2 and the outer frame 1.

[0035] The working method of the above-mentioned simulated mining earthquake source rupture test device includes the following steps:

[0036] S1. Prepare rock samples: Select representative rocks from the target mining area to prepare rock samples 7. The rock samples 7 should be in a cubic shape to ensure that they can fit into the sample placement space.

[0037] S2. Fixing the acoustic emission probes of the acoustic emission acquisition system to both sides of the rock sample 7 using a coupling agent to collect the acoustic emission signals during the rock fracture process in real time;

[0038] S3. Place the assembled test device in a triaxial testing machine so that the triaxial testing machine can apply tension or pressure to the inner frame 2 and apply pressure to the two shear stress loading components 3;

[0039] S4, fixing the rock sample 7 in the sample placement space;

[0040] S5. Determine the loading method according to the type of rupture of the mine earthquake source to be simulated, specifically: if the target mine earthquake source rupture type is compression-shear composite rupture, control the triaxial testing machine to apply tension to the inner frame 2 and pressure to the two shear stress loading components 3 at the same time, so as to load the compressive stress and shear stress on the rock sample 7; if the target mine earthquake source rupture type is tension-shear composite rupture, control the triaxial testing machine to apply pressure to the inner frame 2 and pressure to the two shear stress loading components 3 at the same time, so as to load the tensile stress and shear stress on the rock sample 7; when it is necessary to apply tensile stress to the rock sample 7, first bond the upper and lower ends of the rock sample 7 to the upper clamping component 4 and the lower clamping component 5 respectively by adhesive, and then apply a tensile test to the rock sample 7. Figure 3 As shown, the earthquake source rupture types are divided into five types of rupture according to the different proportions of the isotropic component (ISO) and the double couple component (DC) in the earthquake source moment tensor, namely pure tension, tension-shear, pure shear, compression-shear and pure compression. Among them, the mine earthquake in the mine overburden environment is dominated by compression-shear composite rupture and tension-shear composite rupture. The specific classification method of the two rupture types is as follows: compression-shear composite rupture: ISO < 0%, 40% ≤ DC < 60%; tension-shear composite rupture: ISO > 0%, 40% ≤ DC < 60%; This embodiment designs a loading method for these two types of rupture types; when performing a compression-shear test, the prepared rock sample 7 is placed in the sample placement space between the upper clamping part 4 and the lower clamping part 5, and a small pre-tightening force is applied to increase the friction force to ensure that the sample will not slip at the initial loading stage; if a tension-shear test is to be performed, the lower contact surface of the upper clamping part 4 and the upper contact surface of the lower clamping part 5 need to be cleaned. For the contact surface and the upper and lower end faces of the rock sample 7, high-strength, fast-curing epoxy resin structural adhesive is selected. The operation is carried out strictly in accordance with the adhesive instructions, and the mixture is evenly mixed in proportion. A layer of adhesive is evenly applied on the two end faces of the sample and the contact surface of the clamping component. Then the rock sample is quickly placed on the lower clamping component 4 and aligned in position. A clamp or a heavy object is used to keep the sample in place. The sample is cured for a sufficiently long time under the specified temperature and humidity conditions until the adhesive reaches the bonding strength specified in the instructions. A triaxial testing machine is used to apply load according to the determined type, and the loading is continued until the rock sample is destroyed. When simulating a compression-shear type mine earthquake, stress loading is required on the upper side of the outer frame 1 and the lower side of the inner frame 2, and stress loading is also required on the shear stress loading component 3. When simulating a tension-shear type mine earthquake, stress loading is required on the lower side of the outer frame 1 and the upper side of the inner frame 2, and stress loading is also required on the shear stress loading component 3. Finally, the acoustic emission data corresponding to the rupture process of different mine earthquake sources are obtained.

[0041] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A test device for simulating the source rupture of a mine earthquake, characterized in that: It includes an outer frame, an inner frame, an upper clamping component, a lower clamping component, a sliding base and two shear stress loading components; The outer frame is provided with a slide groove, the inner frame is mounted on the outer frame, and both sides of the inner frame are in the slide groove, so that the inner frame slides up and down relative to the outer frame along the slide groove; The sliding base is fixed to the inner frame, and a horizontal sliding groove is provided at the upper end of the sliding base. The lower portion of the lower clamping member is mounted in the horizontal sliding groove and can move relative to the sliding base along the horizontal sliding groove. The upper clamping member is mounted on the outer frame, and the upper clamping member and the lower clamping member are arranged relative to each other to form a sample placement space therebetween for placing the rock sample. The two shear stress loading components are respectively located on both sides of the sample placement space, one end of one shear stress loading component passes through the outer frame and the inner frame and contacts the side of the upper clamping component, and one end of the other shear stress loading component passes through the outer frame and the inner frame and contacts the side of the lower clamping component; when pressure or tension is applied to the rock sample, the upper clamping component and the lower clamping component are driven to apply the required stress to the rock sample by applying tension or pressure to the inner frame; when shear force is applied to the rock sample, pressure is applied to the two shear stress loading components at the same time, thereby driving the lower clamping component to move relative to the upper clamping component along the horizontal sliding groove, thereby applying the required shear force to the rock sample.

2. The test device for simulating mine earthquake source rupture according to claim 1, characterized in that: The outer frame includes two rectangular frames, which are mirror-symmetrical and connected by bolts; sliding grooves are symmetrically provided on both sides of the two rectangular frames for installing the inner frame.

3. The test device for simulating the source rupture of a mine earthquake according to claim 1, characterized in that: The inner frame is a rectangular parallelepiped frame.

4. The test device for simulating mine earthquake source rupture according to claim 1, characterized in that: The upper clamping part and the lower clamping part are both U-shaped components.

5. The test device for simulating mine earthquake source rupture according to claim 1, characterized in that: The upper clamping component and the outer frame, the sliding base and the inner frame are all fixedly connected by bolts; the horizontal sliding groove of the sliding base is a T-shaped sliding groove, and the lower part of the lower clamping component is provided with a downwardly protruding T-shaped guide rail, which is installed in the T-shaped sliding groove to realize horizontal sliding of the lower clamping component relative to the sliding base.

6. The test device for simulating mine earthquake source rupture according to claim 1, characterized in that: The shear stress loading component is a T-shaped loading component. Both sides of the outer frame and the inner frame are provided with strip-shaped through holes along the slide groove, so as to allow the shear stress loading component to pass through the outer frame and the inner frame.

7. A method for operating the device for simulating mining earthquake source rupture testing according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Prepare rock samples; S2. Fixing the acoustic emission probes of the acoustic emission acquisition system on both sides of the rock sample to collect the acoustic emission signals during the rock fracture process in real time; S3. placing the assembled test apparatus in a triaxial testing machine, so that the triaxial testing machine can apply tension or compression to the inner frame and apply compression to the two shear stress loading components; S4. Fix the rock sample in the sample placement space; S5. Determine the loading method based on the type of mining earthquake source rupture to be simulated, apply the load using a triaxial testing machine, and continue loading until the rock sample fails, obtaining acoustic emission data corresponding to different mining earthquake source rupture processes.

8. The working method according to claim 7, characterized in that: The step S5 determines the loading method according to the type of mine earthquake source rupture to be simulated, specifically: if the target mine earthquake source rupture type is compression-shear composite rupture, the triaxial testing machine is controlled to apply tension to the inner frame and pressure to the two shear stress loading components at the same time, so as to realize compressive stress and shear stress loading on the rock sample; if the target mine earthquake source rupture type is tension-shear composite rupture, the triaxial testing machine is controlled to apply pressure to the inner frame and pressure to the two shear stress loading components at the same time, so as to realize tensile stress and shear stress loading on the rock sample.

9. The working method according to claim 7, characterized in that: When tensile stress needs to be applied to the rock sample, the upper and lower ends of the rock sample are first bonded and fixed to the upper clamping component and the lower clamping component respectively by adhesives, and then a tensile test is applied to the rock sample.

Images