Freezing fractured rock mass blasting model test device

Abstract

The utility model discloses a frozen fractured rock mass blasting model test device, which comprises a rock mass blasting model, an infrared thermal imager, a three-dimensional laser scanner and a shell, the rock mass blasting model is arranged in the shell, a stress sensor is pre-buried in the rock mass blasting model, fractures and blast holes are arranged in the rock mass blasting model, and the infrared thermal imager and the three-dimensional laser scanner are arranged in the shell. Explosives and detonators are mounted in the blast holes, and the infrared thermal imager and the three-dimensional laser scanner are both mounted above the rock blasting model. The utility model has the beneficial effects that the stress sensor is pre-embedded in the rock mass blasting model to collect stress waveform data during blasting, the infrared thermal imager records temperature change and energy dissipation process during blasting, and the three-dimensional laser scanner scans the forms of the model test piece before and after blasting. The fracture form and the energy dissipation characteristic of the frozen ice crack rock mass under the explosive blasting effect are obtained, and reference is provided for parameter optimization of frozen crack rock mass blasting.

Description

Technical Field

[0001] The utility model relates to the technical field of rock mass blasting test, in particular to a frozen crack rock mass blasting model test device. Background Art

[0002] Due to geological structure, weathering and construction disturbance, the rock mass in high-altitude and cold areas contains a large number of initial defects such as cracks, joints and faults. Cracks can store meltwater, summer rainfall and underground seepage. Under the special climatic conditions in cold areas, the water in the cracks will freeze. The rock medium and the ice medium in the cracks together form frozen ice-cracked rock mass, whose physical and mechanical properties are significantly different from those of conventional cracked rock mass and frozen intact rock mass. This type of rock is difficult to blast and excavate. Even if the unit consumption of explosives is continuously increased, the rate of blasting large blocks is still very high. On the other hand, because the cracks in the rock mass are basically filled with ice, the blasting vibration decays slowly and propagates over a long distance, which has a great impact on surrounding structures. This reflects that there are significant differences in the impact dynamics characteristics of frozen ice-cracked rock mass and conventional cracked rock mass.

[0003] At present, the blasting model tests on frozen fractured rock mass are mainly carried out through uniaxial compression test, Brazilian disc splitting test, indoor separated Hopkinson pressure bar test and air cannon test. The above tests can only simulate impact loads with lower strain rates, but cannot simulate real blasting loads. They cannot obtain the fracture morphology and energy dissipation characteristics of frozen ice fractured rock mass under the action of explosive blasting, and cannot provide a reference for parameter optimization of frozen fractured rock mass blasting. Summary of the invention

[0004] The utility model aims to provide a frozen fractured rock mass blasting model test device, which simulates the real blasting load, obtains the fracture morphology and energy dissipation characteristics of frozen ice fractured rock mass under the blasting action of explosives, and provides a reference for parameter optimization of frozen fractured rock mass blasting.

[0005] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme.

[0006] A frozen crack rock blasting model test device comprises a rock blasting model, an infrared thermal imager, a three-dimensional laser scanner and a shell, wherein the rock blasting model is installed in the shell, a stress sensor is pre-buried in the rock blasting model, cracks and blast holes are arranged in the rock blasting model, explosives and detonators are installed in the blast holes, and the infrared thermal imager and the three-dimensional laser scanner are both installed above the rock blasting model.

[0007] The utility model adopting the above scheme, by installing the rock blasting model in the shell, is convenient for reducing the interference of the reflected wave during the explosion through the shell, while ensuring sufficient peripheral constraint strength. Cracks are also set in the rock blasting model, and ice is set in the cracks to simulate the frozen ice-cracked rock structure, and blast holes are set, which are convenient for installing explosives and detonators in the blast holes, so that the explosives can be detonated by igniting the detonators to explode the rock blasting model, and stress sensors are pre-buried in the rock blasting model to collect stress waveform data during the explosion, and the temperature changes and energy dissipation process during the blasting process are recorded by an infrared thermal imager. The morphology of the model specimen before and after the explosion is scanned by a three-dimensional laser scanner, and the crack width and blasting funnel size after the explosion are calculated, and the fracture morphology and energy dissipation characteristics of the frozen ice-cracked rock under the action of explosive blasting are obtained, providing a reference for parameter optimization of frozen cracked rock blasting.

[0008] Preferably, the outer shell is a cylindrical shell as a whole, and the top and the bottom of the outer shell are both set to be open.

[0009] In this way, the top and bottom of the shell are set to be open, which is convenient for detonating the detonator and recording the temperature changes and energy dissipation process during the blasting process through an infrared thermal imager. The three-dimensional laser scanner scans the morphology of the model specimen before and after the explosion, and calculates the crack width after the explosion and the size of the blasting funnel.

[0010] Preferably, the shell is made of high wave impedance material, and the thickness δ of the shell satisfies δ≥2.5 d ,in d is the borehole diameter.

[0011] In this way, it is convenient to reduce the interference of reflected waves through the high wave impedance material shell while ensuring sufficient peripheral constraint strength.

[0012] Preferably, the fissure is located at the upper end of the rock blasting model, and the fissure is filled with ice.

[0013] This makes it easier to simulate the actual characteristics of frozen fractured rock mass more accurately.

[0014] Preferably, the gap at the largest point of the crack is no greater than 0.2 Φ The maximum depth of the crack is no more than 0.5 d， in Φ is the diameter of the rock blasting model, d is the diameter of the blasthole, and the blasthole is generally circular.

[0015] In this way, the gap at the largest crack is no larger than 0.2 Φ The maximum depth of the crack is no more than 0.5 d， in Φ is the diameter of the rock blasting model,d The diameter of the blasthole is basically consistent with the on-site cracks. The crack size is limited to meet the size restrictions of the concrete model and avoid boundary effects.

[0016] Preferably, the rock blasting model is cylindrical, and the diameter of the rock blasting model is Φ Greater than the model's height H 1.

[0017] In this way, it is easy to ensure that the strength of the rock blasting model is basically consistent with the strength of the actual rock mass.

[0018] Preferably, the blasthole extends vertically from the top to the bottom of the rock blasting model.

[0019] In this way, it is easy to make the rock blasting model be subjected to uniform force when the explosives explode.

[0020] Preferably, the stress sensors are provided in plurality, and the sensors located on the same side of the blasthole are arranged on the same horizontal straight line, and the depth H4 of the arrangement of the stress sensors satisfies H 3< H 4< H 2, where H 2 is the depth of the blasthole, H 3 is the filling depth.

[0021] In this way, stress sensors are pre-buried according to experimental requirements to meet the needs of regression analysis of stress wave attenuation laws.

[0022] Preferably, it further comprises a high-speed camera, which is installed above the rock blasting model.

[0023] In this way, a high-speed camera is set up to record the expansion process of the explosion cracks.

[0024] Preferably, a stress data collector is further included, and the stress sensor is connected to the stress data collector via a data transmission line.

[0025] In this way, it is convenient to display the stress waveform data collected by the stress sensor during the explosion through the stress data acquisition instrument.

[0026] The beneficial effect of the utility model is that by installing the rock blasting model in the shell, the interference of the reflected wave during the explosion can be reduced through the shell, while ensuring sufficient peripheral constraint strength. A crack is also set in the rock blasting model to simulate the frozen ice crack rock structure, and explosives and detonators are installed in the blasthole, so that the rock blasting model can be detonated by igniting the detonator to detonate the explosives, and stress waveform data during the explosion is collected by pre-embedded stress sensors in the rock blasting model, and the temperature change and energy dissipation process during the blasting process are recorded by an infrared thermal imager. A three-dimensional laser scanner scans the shape of the model specimen before and after the explosion, and a high-speed camera is set to record the expansion process of the blasting crack. The crack width after the explosion and the size of the blasting funnel are calculated, and the fracture shape and energy dissipation characteristics of the frozen ice crack rock under the action of explosive blasting are obtained, providing a reference for parameter optimization of frozen crack rock blasting. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic structural stereogram of the utility model;

[0028] Figure 2 It is a top view of the utility model.

[0029] Figure 3 This utility model Figure 2 Enlarged view of the K part. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings, but the present invention is not limited to the scope of the embodiments described.

[0031] The figure marks in the drawings of the specification include: rock blasting model 1, shell 2, stress data acquisition instrument 3, infrared thermal imager 4, camera 5, three-dimensional laser scanner 6, blast hole 7, crack 8, stress sensor 9, explosive 10, detonator 11, filling 12, ice 13, data transmission line 14.

[0032] The words "first", "second" and similar words used in the embodiments of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "one", "an" or "the" and similar words do not indicate a quantity limitation, but rather indicate the presence of at least one. Similarly, words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections or communication connections, whether direct or indirect.

[0033] Embodiment 1, as Figure 1, Figure 2 and Figure 3 as shown in. The present application provides a blasting model test device for frozen fractured rock masses, including a rock mass blasting model 1, an infrared thermal imager 4, a three-dimensional laser scanner 6, and a housing 2. The rock mass blasting model 1 is installed inside the housing 2. Stress sensors 9 are embedded in the rock mass blasting model 1. Fractures 8 and blast holes 7 are provided in the rock mass blasting model 1. Explosives 10 and detonators 11 are installed in the blast holes 7. The infrared thermal imager 4 and the three-dimensional laser scanner 6 are both installed above the rock mass blasting model 1.

[0034] See Figure 1 , Figure 2 and Figure 3 as shown in. The housing 2 is integrally a cylindrical shell, and both the top and bottom of the housing 2 are open. The housing 2 is made of a high wave impedance material, and the thickness δ of the housing 2 satisfies δ≥2.5d, where d is the diameter of the blast hole 7. The maximum gap of the fracture 8 is not greater than 0.2Φ, and the maximum depth of the fracture 8 is not greater than 0.5d, where Φ is the diameter of the rock mass blasting model 1. The blast hole 7 is integrally circular, and d is the diameter of the blast hole 7. The rock mass blasting model 1 is cylindrical, and the diameter Φ of the rock mass blasting model 1 is greater than the height H1 of the model. The blast hole 7 extends vertically from the top to the bottom of the rock mass blasting model 1. Several stress sensors 9 are provided, and the sensors located on the same side of the blast hole 7 are arranged on the same horizontal line. The depth H4 at which the stress sensors 9 are arranged satisfies H3<H4<H2, where H2 is the depth of the blast hole 7 and H3 is the depth of the filler 12. It further includes a high-speed camera 5, and the high-speed camera 5 is installed above the rock mass blasting model 1. It further includes a stress data collector 3, and the stress sensors 9 are connected to the stress data collector 3 through a data transmission line 14.

[0035] Specifically, to simulate the blasting fragmentation mechanical properties of a certain frozen fractured rock mass 8, the compressive strength of the frozen fractured rock mass 8 is 35 Mpa. The designed diameter d of the prefabricated blast hole 7 is 30 mm, the depth H2 of the blast hole 7 is 600 mm, and the length H3 of the filler 12 is 150 mm.

[0036] First step, fabricate the housing 2 of high wave impedance material. Since the designed concrete density is 2300 kg / m3 and the wave velocity is 2800 m / s, its wave impedance Z 1 = ρ 1C p1 = 2300 kg / m 3 × 2800 m / s = 6.44×10 6 kg▪m -2 ▪s -1 . Therefore, brass is selected to fabricate the housing 2 of the model, satisfying the wave impedance Z2 = 8900 kg / m 3 × 4700 m / s ≥ 2 Z 1. To further reduce the interference of reflected waves and ensure sufficient peripheral constraint strength, the thickness of the brass shell 2 satisfies δ ≥ 2.5 × 30 mm = 75 mm, and the shell 2 may not be provided at the bottom of the model.

[0037] Second step, pour the cylindrical concrete model. Adjust its finished strength by adjusting the cement type, concrete strengthening agent, manufactured sand type, aggregate gradation, water-cement ratio, curing environment, etc., to ensure that the strength is basically the same as that of the simulated rock mass, that is, the compressive strength is 35 Mpa. The height of the model satisfies H1 > 2 × 600 mm = 1200 mm, take H1 = 1500 mm, and the diameter of the model satisfies Φ > H1 = 1500 mm, take Φ = 1800 mm.

[0038] Third step, preset the blast hole 7 and the prefabricated crack 8. Refer to Figure 2 and Figure 3 When pouring the concrete model, a prefabricated blast hole 7 is provided in the cylindrical concrete model. The designed diameter d of the prefabricated blast hole 7 is 30 mm, and the depth H2 of the blast hole 7 is 600 mm. And a set of cracks 8 are preset when pouring the concrete model. The prefabricated cracks 8 partially outcrop at the upper end of the cylindrical concrete model to facilitate injecting water to make ice 13 in the cracks 8 before the test. The maximum size of the prefabricated crack 8 is not greater than 0.2 × 1500 mm = 300 mm, and the depth is not greater than 0.5 × 30 mm = 12.5 mm.

[0039] Fourth step, embed the stress sensor 9. When pouring the concrete model, embed the stress sensor 9 according to the experimental requirements. To meet the needs of the regression analysis of the stress wave attenuation law, the number of embedded sensors in this embodiment is 9, and the sensors on one side of the blast hole 7 should be arranged in a straight line, as Figure 2 shown. The depth of the sensor arrangement satisfies 150 mm < H4 < 600 mm, and in this embodiment, take H4 = 300 mm; when burying, extend the data transmission line 14 connected to the embedded stress sensor 9 outside the concrete model in advance.

[0040] Fifth step, make ice 13 in the frozen crack 8 rock mass. Before the blasting test, first inject clear water (temperature 0 - 2 °C) into the crack 8 from the outcrop at the upper part of the cylindrical concrete model through the prefabricated type, and then the water in the crack 8 can be quickly frozen into ice 13 by liquid nitrogen.

[0041] Sixth step, charge and tamp 12. Load the explosive 10 and detonator 11 according to the blasting requirements, and tamp the blast hole 7 with the tamp 12. The charging length is 450 mm, and the length of the tamp 12 is H3 = 150 mm.

[0042] Step 7: Arrange the instruments. Connect the data transmission line 14 connected to the pre-buried stress sensor 9 to the stress data acquisition instrument 3, and place the instrument at a safe distance and take protective measures; arrange the infrared thermal imager 4, high-speed camera 5 and three-dimensional laser scanner 6 at a safe distance, and set the parameters of each acquisition device.

[0043] Step 8: blast and recover the equipment. Detonate under the premise of ensuring a safe distance and taking safety protection measures, use stress waveform data through stress data acquisition instrument 3, record temperature changes and energy dissipation process during blasting through infrared thermal imager 4, use high-speed camera 5 to record the expansion process of blasting cracks, and use three-dimensional laser scanner 6 to scan the morphology of the model specimen before and after blasting, and calculate the crack width after blasting and the size of blasting funnel. Then recover the equipment.

[0044] The preferred specific embodiments of the utility model are described in detail above. It should be understood that ordinary technicians in this field can make many modifications and changes based on the concept of the utility model without creative work. Therefore, all technical solutions that can be obtained by technicians in this technical field based on the concept of the utility model through logical analysis, reasoning or limited experiments on the basis of the existing technology should be within the scope of protection determined by the claims.

Claims

1. A frozen fracture rock blasting model test device, characterized in that: It includes a rock mass blasting model (1), an infrared thermal imager (4), a stress data collector (3), a three-dimensional laser scanner (6) and a housing (2). The rock mass blasting model (1) is installed inside the housing (2). Stress sensors (9) are embedded in the rock mass blasting model (1), and the stress sensors (9) are connected to the stress data collector (3) through data transmission lines (14). Fissures (8) and blast holes (7) are arranged in the rock mass blasting model (1). The infrared thermal imager (4) and the three-dimensional laser scanner (6) are both installed above the rock mass blasting model (1).

2. The frozen fracture rock blasting model test device according to claim 1, characterized in that: The housing (2) is integrally a cylindrical shell, and both the top and bottom of the housing (2) are open-ended.

3. The frozen fracture rock blasting model test device according to claim 1, characterized in that: The housing (2) is made of a material with a high wave impedance, and the thickness δ of the housing (2) satisfies δ≥2.5d, where d is the diameter of the blast hole (7).

4. The frozen fracture rock blasting model test device according to claim 1, characterized in that: The fissure (8) is located at the upper end of the rock mass blasting model (1).

5. The frozen fracture rock blasting model test device according to claim 2, characterized in that: The rock mass blasting model (1) is cylindrical, and the rock mass blasting model (1) is fitted to the inner side of the housing (2). The diameter Φ of the rock mass blasting model (1) is greater than the height H1 of the rock mass blasting model (1).

6. The frozen fracture rock blasting model test device according to claim 1, characterized in that: The maximum gap of the fissure (8) is not greater than 0.2Φ, and the maximum depth of the fissure (8) is not greater than 0.5d, where Φ is the diameter of the rock mass blasting model (1). The blast hole (7) is integrally circular, and d is the diameter of the blast hole (7).

7. The frozen fracture rock blasting model test device according to claim 1, characterized in that: The blast hole (7) extends vertically from the top to the bottom of the rock mass blasting model (1).

8. The frozen fracture rock blasting model test device according to claim 7, characterized in that: Several stress sensors (9) are provided. The sensors located on the same side of the blast hole (7) are arranged on the same horizontal straight line. The depth H4 at which the stress sensors (9) are arranged satisfies H3<H4<H2, where H2 is the depth of the blast hole (7) and H3 is the depth of the stuffing (12) of the blast hole (7).

9. The frozen fracture rock blasting model test device according to any one of claims 1 to 8, characterized in that: It further includes a high-speed camera (5), and the high-speed camera (5) is installed above the rock mass blasting model (1).

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