Concrete structure damage effect acquisition device based on shaped charge jet blasting

Abstract

The application discloses a kind of concrete structure damage effect collection devices based on shaped charge jet blasting, including test pier, concrete base block, sensor group;Wherein test pier includes shell and the concrete structure that is poured in shell, concrete base block is same with concrete structure material, linear distribution in concrete structure, as the carrier of sensor, ensure that when external shaped charge blasting device explodes, the blasting performance of blasting device is correctly reacted;The present application is provided with velocity measurement screen target on the upper and lower end surface of concrete base block, the signal generated by each layer of screen target is used to judge the penetration depth of shaped charge blasting device in concrete structure and the change of jet velocity, which is beneficial to judge the jet penetration depth and velocity of shaped charge blasting device at different blasting height.

Description

TECHNICAL FIELD

[0001] The present application relates to a concrete structure damage effect collection device based on shaped charge jet blasting, and belongs to the technical field of blasting damage. BACKGROUND

[0002] In some concrete building facilities, it is often necessary to destroy the concrete structure by blasting, especially some concrete piers in the shape of a cone. Generally, the blasting can be performed by grouping the charge. In order to achieve better damage effect, a shaped charge blasting device can also be used. However, the shaped charge blasting device is sensitive to explosives. Different blasting heights have different damage effects on concrete. After the concrete structure is blasted, it is impacted by the metal jet and at the same time the stress of the explosion is brought, so that the concrete structure is fragmented and the jet hole of the concrete structure cannot be obtained, so the depth of the explosive penetration and the change of the stress between the concrete structures cannot be reflected.

[0003] The prior art is to cut the metal target after blasting to obtain the damage section of the shaped charge blasting to judge the penetration effect of the shaped charge structure. However, only static images can be seen. When a high-speed camera is used to shoot the picture at the moment of damage, the internal damage effect and the stress change cannot be known. Therefore, how to obtain the damage effect of the shaped charge blasting device in the concrete structure becomes a problem to be solved. SUMMARY

[0004] The present application aims to overcome the shortcomings of the prior art and provide a concrete structure damage effect collection device based on shaped charge jet blasting, which can reflect the depth of explosive penetration and the change of stress between the concrete structures.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present application is:

[0006] The present application provides a concrete structure damage effect collection device based on shaped charge jet blasting, characterized in that it comprises a test pier, a plurality of concrete base blocks and a sensor group.

[0007] The test pier comprises a shell and a concrete structure poured in the shell. The concrete base blocks are linearly distributed inside the concrete structure and are integrally poured and formed with the concrete structure. Once it can not only ensure the consistency of the strength of the concrete structure, but also can reduce the stress propagation interruption caused by layering and ensure the accuracy of the test results of the concrete base blocks after shaped charge blasting. The shell is arranged in the form of a conical frustum or a cube.

[0008] The sensor group comprises a velocity measurement net target, a strain sensor, a stress sensor and a wall surface pressure sensor connected with an upper computer through an acquisition circuit, the velocity measurement net target is attached to the upper and lower end surfaces of the concrete base block, the strain sensor is attached to the upper end surface and the side surface of the concrete base block, the stress sensor is located above the concrete base block, and the wall surface pressure sensor is located on the side wall of the shell.

[0009] Further, the acquisition circuit comprises a first data collector and a second data collector, the velocity measurement net target and the strain sensor are connected with the upper computer through the first data collector, and the wall surface pressure sensor is connected with the upper computer through the second data collector.

[0010] Further, the velocity measurement net target comprises serpentine distributed metal wires, the distance between adjacent metal wires is 5mm, so that the signal test is not incomplete due to the too large distance.

[0011] Further, the velocity measurement net target generates an electric signal when being disconnected.

[0012] Further, the height of the concrete base block is 75mm, the distance between the concrete base blocks is 100mm, and the distance between the uppermost velocity measurement net target and the top surface of the test pier body is 275mm, so that the law of jet decay can be detected.

[0013] Further, the sensitive surface of the stress sensor faces upwards and is located at the middle position above the concrete base block.

[0014] Further, the strain sensor attached to the top surface of the concrete base block outputs X-direction and Y-direction strain information, and the strain sensor attached to the side surface of the concrete base block outputs X-direction and Z-direction strain information.

[0015] Further, the support rod parallel to the plurality of concrete base blocks is further included for limiting connection of the concrete base blocks.

[0016] Further, the stress sensor is fixed to the surface of a vertical angle steel, so that the position of the stress sensor is prevented from being changed during the process of pouring concrete in the shell, and the test result is affected.

[0017] Compared with the prior art, the present application has the following beneficial effects:

[0018] In the present application, the concrete base block of the same material is arranged in the concrete pier body as the carrier of the strain sensor, so that the penetration path and depth of the blasting product in the concrete structure are not affected after the external energy-gathering blasting device is blasted, and the blasting effect of the blasting device is correctly reflected.

[0019] The present application sets the velocity measurement net target on the upper and lower end faces of the concrete base block, judges the penetration depth of the shaped charge blasting device in the concrete structure and the change of the jet velocity through the signals generated by the net targets of each layer;

[0020] The strain sensor is set on the concrete base block, the parameters of the penetration depth and the jet velocity are matched, the penetration depth of the jet under different blasting heights is obtained, especially the change of the concrete strain data at different penetration depths, and the damage effect of the concrete structure when the shaped charge blasting device is at different blasting heights and different charge forms is obtained. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a whole structure schematic diagram of a concrete structure damage effect collection device based on shaped jet blasting according to an embodiment of the present application;

[0022] Figure 2 It is a structure schematic diagram of a test pier according to an embodiment of the present application;

[0023] Figure 3 It is a structure schematic diagram of the distribution of the sensor group in the test pier according to an embodiment of the present application;

[0024] Figure 4 It is a structure schematic diagram of a concrete base block according to an embodiment of the present application;

[0025] Figure 5 It is a schematic diagram of the distribution of the velocity measurement net target according to an embodiment of the present application;

[0026] Figure 6 It is a photo of the damage of the test pier according to the third embodiment of the present application, wherein (a)-(d) in the photo are the photos of the damage of the test pier when the blasting height is 15cm, 20cm, 30cm and 40cm respectively;

[0027] Figure 7 It is a strain waveform diagram collected by different strain sensors according to the fourth embodiment of the present application;

[0028] In the figure: 10, concrete base block; 11, support rod; 12, velocity measurement net target; 13, first strain sensor; 14, second strain sensor; 20, stress sensor; 21, angle steel; 30, wall surface pressure sensor; 40, first data collector; 50, second data collector; 100, test pier; 200, electric detonator. DETAILED DESCRIPTION

[0029] The present application will be further described below in combination with the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0030] The shaped charge structure is mainly divided into EPF structure and JPC structure. Among them, the EPF structure has a shallow penetration depth but a large diameter; the JPC structure has a deep penetration depth but a small diameter. In the experiment, this invention mainly focuses on the EPF structure and the JPC structure, and divides the experiment into two groups. The test is carried out at different heights in each group to determine the blasting damage effect of the two main shaped charges.

[0031] Combination Figures 1-3 As shown, the present invention proposes a device for collecting the damage effects of concrete structures based on shaped charge jet blasting, which mainly includes a test pier 100, a concrete base block 10, a sensor group, and a collection circuit.

[0032] The test pier 100 includes a shell and a concrete structure cast within the shell. The shell is configured in a frustum shape to simulate the frustum-shaped concrete structure to be tested. In other embodiments, the shell may be replaced with other shapes, such as prisms or cubes, depending on the concrete structure to be tested.

[0033] Furthermore, the concrete blocks 10 are linearly distributed in the concrete structure. Since the shaped charge structure is fixed above the test pier 100 and the blasting action is carried out from top to bottom, the specific penetration depth and penetration velocity of the shaped charge can be determined through the three linearly distributed concrete blocks 10. In particular, the change in penetration velocity cannot be obtained from the external camera or the cross-sectional view of the concrete structure after the blast.

[0034] Preferably, in order to ensure that the concrete base block 10 does not affect the overall material and mechanical properties, the concrete base block 10 is set in a cubic shape, and the concrete base block 10 is made of the same material as the concrete structure, and the concrete base block 10 is integrally formed with the subsequently poured concrete structure.

[0035] Combination Figures 2-4 As shown, the sensor group includes a velocity measuring net target 12, a strain sensor, a stress sensor 20, and a wall pressure sensor 30. The velocity measuring net target 12 is attached to the upper and lower end faces of each concrete block 10. The strain sensor is attached to the top and side faces of each concrete block 10. The stress sensor 20 is located above each concrete block 10. The wall pressure sensor 30 is located on the side wall of the housing. The velocity measuring net target 12, the strain sensor, the stress sensor 20, and the wall pressure sensor 30 are connected to the host computer through a data acquisition circuit.

[0036] Combination Figure 1 As shown, the acquisition circuit includes a first data acquisition unit 40 and a second data acquisition unit 50. The speed measuring net target 12 and the strain sensor are connected to the host computer through the first data acquisition unit 40, the stress sensor 20 is connected to the host computer, and the wall pressure sensor 30 is connected to the host computer through the second data acquisition unit 50.

[0037] Both the first and second data acquisition units use the DH5902 model data acquisition unit.

[0038] Specifically, in combination Figure 4 As shown, the speed measuring target 12 includes a serpentine distributed metal wire. The speed measuring target 12 is electrically connected to the acquisition circuit. When the speed measuring target 12 is disconnected, an electrical signal is generated.

[0039] Furthermore, the strain sensor located on the top surface of the concrete block 10 is defined as the first strain sensor 13, and the strain sensor located on the side of the concrete block 10 is defined as the second strain sensor 14. The first strain sensor 13 points to the X and Y directions, and the second strain sensor 14 points to the X and Z directions.

[0040] The first strain sensor 13 and the second strain sensor 14 can be selected from the BQ120-5AA and BE120-5AA series strain gauges of AVIC Electromechanical Measurement.

[0041] The strain testing system consists of the strain gauges, 4-core shielded cables, DH8302 data acquisition unit, and host computer.

[0042] Using multi-core shielded cables can improve the accuracy of testing and avoid interference from external signals on the strain signals acquired by each strain gauge.

[0043] Furthermore, in order to increase the accuracy of strain testing, the strain gauge and the concrete base block 10 should be kept in good contact during installation.

[0044] Example 1

[0045] The installation method for strain sensors is as follows:

[0046] ① Use a wet grinding wheel to grind the center of the top surface (top surface strain) and the center of the side surface (side strain) of the test specimen.

[0047] ② Grind the area of ​​the strain gauge after water grinding. Grind at a 45° angle to the cross according to the direction of the strain gauge. First use 180 grit sandpaper for coarse grinding, and then use 400 grit sandpaper for fine grinding to optimize the surface roughness.

[0048] ③ For areas where AB glue will be applied after sanding, wipe the surface with industrial alcohol to remove dust;

[0049] ④ Use a pencil to outline the boundaries of the designated area;

[0050] ⑤ Apply an appropriate amount of well-stirred AB glue to the strain gauge patch area and wait for it to cure;

[0051] ⑥ According to the strain gauge direction, grind the AB glue area at a 45° angle, and use 400-grit sandpaper to optimize the surface roughness and the thickness of the AB glue.

[0052] ⑦ After sanding the AB glue area, wipe it with industrial alcohol to remove surface dust.

[0053] ⑧ Use 10-second slow-drying 502 glue to attach the strain gauge and terminals to the patch area; there should be a gap of about 5mm between the strain gauge and the terminals.

[0054] ⑨ Use soldering to connect strain gauges to terminals, and terminals to leads;

[0055] ⑩ Apply Nanda 703 silicone rubber evenly to the strain gauge area and wiring area. After applying the silicone rubber, press it gently with your fingertip to remove air bubbles. The silicone rubber will be fully cured after 24 hours.

[0056] Combination Figure 5 As shown, the distance between the top and bottom surfaces of the concrete base block 10 is 75mm, the distance between two adjacent concrete base blocks 10 is 100mm, and the distance between the topmost speed measuring net target 12 and the top surface of the test pier 100 is 275mm.

[0057] Based on the signal generation time of the velocity measuring target 12 and the distance between the target 12 and the velocity measuring net, the change in penetration velocity can be obtained, and the position of penetration depth can also be obtained.

[0058] In this embodiment, the outer sides of the three concrete base blocks 10 are provided with grooves and are snapped onto a pair of support rods 11. The support rods 11 are used to limit the relative position of the concrete base blocks 10 so that the three concrete base blocks 10 are in a predetermined position. In addition, multiple stress sensors 20 are fixed to the surface of a vertical angle steel 21.

[0059] When using the EFP energy-concentrating structure for testing, the stress sensor 20 is located at the upper center of the concrete base block 10, with the sensitive surface of the stress sensor 20 facing upwards.

[0060] When using the JPC energy-concentrating structure for testing, the stress sensor 20 is located on the side of the concrete block 10, and the sensitive surface of the stress sensor 20 faces the central position above the concrete block 10.

[0061] Among them, the stress sensor 20 includes a PVDF piezoelectric sensor. In this embodiment, the DNS113 type PVDF piezoelectric sensor designed by Henan Dynamic Electronics Technology Co., Ltd. was used to measure the internal stress of the concrete pier. The PVDF piezoelectric sensor is flat, with a stainless steel shell, a structural diameter of 40 mm and a thickness of 5 mm.

[0062] Example 2

[0063] The test pier was poured:

[0064] The test pier is fabricated using an integral casting method. First, the concrete base block 10 with the mesh target attached is placed on the mounting bracket and the PVDF sensor is fixed. Then, the concrete is slowly poured in along the edge of the shell. After reaching the predetermined height, the pouring is stopped and the concrete is vibrated to compact it. Then, the concrete structure is poured in and vibrated to compact it again when the predetermined height is reached. This completes the integral casting of the test pier. Compared with layered casting, this method can reduce stress propagation interruptions caused by layering.

[0065] In the actual test, a high-speed camera was set up 50 m away from the test pier to record the damage phenomenon of the concrete pier. The trigger coil was wound around the electric detonator 200, and the on and off of the coil was used as the trigger signal of the test system. The detonation of the electric detonator 200 was controlled by the trigger to realize the synchronous test of dynamic parameters.

[0066] Example 3

[0067] The JPC projectile was tested. Each layer of velocity-measuring net target 12 was connected to an external measuring instrument to form a continuity circuit. After the JPC rod-shaped projectile reached the test block target surface, it broke the metal wire, causing the circuit to break. The measuring instrument recorded the time when the JPC passed through the net target. The average velocity of the JPC passing through the interval between two net targets was calculated by the spacing between each layer of net targets and the time of breakage. The test results are shown in Table 1.

[0068] Table 1: Test Results of Net Targets

[0069]

[0070] Note: "Depth h" represents the distance between each layer of the target mesh and the top surface of the concrete pier; "Time t" represents the time when the target mesh wire breaks; "Average velocity V0" represents the average velocity of JPC penetration within the interval between two target mesh layers; "\" indicates that no experimental data was collected.

[0071] As can be seen from the data in Table 1, the penetration speed in this embodiment exhibits two distinct characteristics. First, the JPC penetration speed is relatively high. As the penetration process progresses, the JPC rod-shaped projectile is eroded, its kinetic energy is continuously consumed, and the penetration speed gradually decreases. Second, the penetration speed gradually increases with the blast height, indicating that the JPC penetration capability gradually increases within the blast height range of 15 cm to 40 cm.

[0072] Example 4

[0073] The EPF charge was tested at a height of 40cm, and the following test parameters were obtained:

[0074] Table 2: Pressure Data

[0075]

[0076] Combined with Table 2 and Figure 7 The strain data shows that as the penetration process proceeds, the difference between the pressure arrival time and the peak arrival time gradually increases, and the penetration speed gradually decreases; the pressure peak decrease rate is significant, the decrease is large, the positive pressure action time gradually decreases, the pressure attenuation caused by the EPF charge explosion is obvious, and the decrease rate is fast.

[0077] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A device for collecting damage effects on concrete structures based on shaped charge jet blasting, characterized in that, This includes the test pier, multiple concrete blocks, and sensor arrays. The test pier includes a shell and a concrete structure cast inside the shell. The concrete blocks are linearly distributed inside the concrete structure and are cast integrally with the concrete structure. The concrete blocks are made of the same material as the concrete structure. The sensor group includes a speed measuring net target, a strain sensor, a stress sensor, and a wall pressure sensor connected to a host computer via a data acquisition circuit. The speed measuring net target is attached to the upper and lower end faces of the concrete base block. The strain sensor is attached to the upper end face and side face of the concrete base block. The stress sensor is located above the concrete base block. The wall pressure sensor is located on the side wall of the housing.

2. The device for collecting damage effects on concrete structures based on shaped-jet blasting according to claim 1, characterized in that, The acquisition circuit includes a first data acquisition unit and a second data acquisition unit. The velocity measuring net target and the strain sensor are connected to the host computer through the first data acquisition unit, and the wall pressure sensor is connected to the host computer through the second data acquisition unit.

3. The device for collecting damage effects on concrete structures based on shaped-jet blasting according to claim 1, characterized in that, The speed measuring net target consists of serpentine metal wires, with a distance of 5 mm between adjacent metal wires.

4. The device for collecting damage effects on concrete structures based on shaped-jet blasting according to claim 1, characterized in that, When the speed measuring net target is disconnected, an electrical signal is generated.

5. The device for collecting damage effects on concrete structures based on shaped-jet blasting according to claim 1, characterized in that, The concrete base is 75mm high, the spacing between the concrete bases is 100mm, and the distance between the topmost speed measuring net target and the top surface of the test pier is 275mm.

6. The device for collecting damage effects on concrete structures based on shaped-jet blasting according to claim 1, characterized in that, The stress sensor has its sensitive surface facing upwards and is located in the middle above the concrete base block.

7. The device for collecting damage effects on concrete structures based on shaped-jet blasting according to claim 1, characterized in that, The strain sensor attached to the top surface of the concrete block outputs strain information in the X and Y directions; the strain sensor attached to the side surface of the concrete block outputs strain information in the X and Z directions.

8. The device for collecting damage effects on concrete structures based on shaped-jet blasting according to claim 1, characterized in that, It also includes support rods parallel to multiple concrete blocks, used to limit the connection of the concrete blocks.

9. The device for collecting damage effects on concrete structures based on shaped-jet blasting according to claim 1, characterized in that, The stress sensor is fixed to the surface of a vertical angle steel.

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