A method and device for monitoring seismic waves from blasting in underground caverns

Abstract

The present invention discloses a method and apparatus for monitoring seismic waves in underground caverns caused by blasting. The method includes measuring the vibration velocity of the cavern roof along the horizontal direction and / or the longitudinal direction; suspending a right-angle reflector on the roof; emitting and receiving reflected laser light from the floor towards the reflector; acquiring the optical deflection displacement, optical path difference, and time interval of the reflected laser light before and after the blast; and obtaining the vibration velocity along the horizontal direction and the vibration velocity along the longitudinal direction using a velocity formula. Specifically, it utilizes a right-angle reflector to reflect the laser light reflected back towards the roof, and uses the optical path difference and optical deflection displacement generated by the laser light's displacement with the right-angle reflector during reflection to indirectly measure the wave velocity of the roof where the right-angle reflector is fixed; it uses a beam splitter to form two optical paths through refraction and reflection to measure the optical path difference and optical deflection displacement separately; and it uses a convex lens to solve the beam offset caused by optical deflection displacement during comprehensive measurement when measuring the optical path difference. The method is simple in structure, easy to operate, and has strong practicality and wide applicability.

Description

Technical Field

[0001] This invention relates to a seismic wave monitoring method, specifically to a method and device for monitoring seismic waves during blasting in underground caverns, belonging to the field of blasting and explosion technology. Background Technology

[0002] Currently, commonly used blasting vibration testing instruments typically mount sensors to the protected target and connect them to the main unit via cables. The sensors can be either permanently mounted to the protected target or removed after each monitoring session and reinstalled for the next. The main unit is powered by a battery, requiring periodic charging (it operates for approximately one day continuously), and needs to be connected to a computer to process the monitoring data after each monitoring session.

[0003] During underground cavern excavation, it is sometimes necessary to monitor the vibration magnitude at the cavern ceiling. Due to the significant height above the ground (4-10m), installing the vibration meter at the cavern ceiling requires removing the main unit for each charging or data processing operation, which is inconvenient. If the sensor is fixed to the cavern ceiling via an extension cable, and the main unit is placed in an easily accessible location, it will lead to signal attenuation, affecting the accuracy of the test results.

[0004] Existing remote vibration meters on the market are fixed at the protected target (in places where it is inconvenient to access), and the data is read via a network. However, there is usually no network in underground caverns, and there are also charging issues.

[0005] Therefore, it is necessary to provide a new method for monitoring seismic waves in underground cavern blasting. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a method for monitoring seismic waves from blasting in underground caverns.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for monitoring seismic waves from blasting in underground caverns includes measuring the vibration velocity of the cavern roof along the horizontal direction and / or along the longitudinal direction. The method is as follows:

[0009] A corner reflector is suspended on the ceiling of the chamber, and the reflected laser is emitted and received from the floor of the chamber. The optical deflection displacement ΔS, optical path difference ΔL, and time interval ΔT of the reflected laser before and after the earthquake are obtained.

[0010] Using the velocity formula:

[0011] The vibration velocity V along the horizontal direction is obtained from the optical polarization displacement ΔS. S ,

[0012] The longitudinal vibration velocity V is obtained from the optical path difference ΔL.L .

[0013] The aforementioned corner mirror is a right-angle mirror; therefore,

[0014] Vibration velocity V along the horizontal direction S =△S / 2△T (1)

[0015] Longitudinal vibration velocity V L =△L / 2△T (2).

[0016] With the point where the right angle of the corner reflector meets the ceiling as the center point and any horizontal direction as the X-axis, establish an XY horizontal coordinate system.

[0017] The horizontal vibration velocity includes the vibration velocity V along the X-axis. X and vibration velocity V along the Y-axis Y ,

[0018] Among them, V X =△S X / 2△T (3)

[0019] V Y =△S Y / 2△T (4)

[0020] In the formula, △S X Let ΔS be the optical deflection displacement of the laser along the horizontal X-axis. Y This represents the optical deflection displacement of the laser beam along the horizontal Y-axis.

[0021] The reflected laser beam is obtained by using a beam splitter to reflect the beam back, and then the coordinates of the first beam reflected by the beam splitter are obtained by using a coordinate measuring device; the optical deflection displacement ΔS of the reflected laser beam before and after the earthquake is obtained based on the coordinates.

[0022] Furthermore, the tilt angle of the aforementioned beam splitter relative to the reflected laser is 45°.

[0023] Furthermore, the second beam of the aforementioned retroreflected laser, passing through the beam splitter, is focused by a convex lens and received by a laser rangefinder to measure the optical path difference ΔL between the retroreflected laser before and after the earthquake.

[0024] A seismic wave monitoring device for underground cavern blasting includes a laser emitting device, a corner reflector, a beam splitter, a coordinate measuring device, a convex lens, and a laser rangefinder;

[0025] The corner reflector is suspended from the ceiling.

[0026] The laser emitting device is located at the bottom of the chamber, and the laser emission angle is along the longitudinal diagonal reflector;

[0027] The beam splitter is positioned in the optical path of the retro-echo laser;

[0028] The coordinate measuring device is used to receive and measure the coordinates of the first beam of the retro-echoed laser reflected by the beam splitter;

[0029] The convex lens is used to converge the second beam of the retroreflected laser light that has passed through the beam splitter;

[0030] The laser rangefinder is used to receive the second light speed and measure the optical path based on the second beam.

[0031] Furthermore, the aforementioned coordinate measuring device samples the first beam at a certain frequency;

[0032] V X =△S X / 2△T =(X i+1 -X i ) / 2 (T i+1 -T i (5)

[0033] V Y =△S Y / 2△T=(Y i+1 - Y i ) / 2 (T i+1 -T i (6)

[0034] In the formula, X i+1 X i The x-components of two adjacent coordinates in the sampling sequence; the y-components of the two coordinates. i+1 Y i T represents the y-component of two adjacent coordinates in the sampling sequence. i+1 T i These are two adjacent sampling times in the sampling sequence.

[0035] Furthermore, the aforementioned laser rangefinder samples the second beam at the same frequency as the coordinate measuring device;

[0036] V L =△L / 2△T i = (L) i+1 - L i ) / 2 (T i+1 -T i (7)

[0037] In the formula, L i+1 L i The L component represents the adjacent samples in the sampling sequence.

[0038] The advantages of this invention are:

[0039] This invention discloses a method and apparatus for monitoring seismic waves from blasting in underground caverns. It utilizes a right-angle mirror to reflect laser light incident on the cavern roof. The optical path difference and optical deflection displacement caused by the laser's displacement with the right-angle mirror during reflection are used to indirectly measure the wave velocity of the protected target (cave roof) of the fixed right-angle mirror. Two optical paths are formed using refraction and reflection by a beam splitter to measure the optical path difference and optical deflection displacement separately. A convex lens is used to address the beam offset caused by optical deflection displacement during comprehensive measurement when measuring the optical path difference.

[0040] The present invention discloses a method and device for monitoring seismic waves from blasting in underground caverns. It has a simple structure, is easy to disassemble, maintain, and relocate, is easy to operate and use, and has high measurement accuracy. It has strong practicality and wide applicability. Attached Figure Description

[0041] Figure 1 To measure the vibration velocity V along the horizontal direction S Optical path schematic diagram;

[0042] Figure 2 To measure the vibration velocity V along the longitudinal direction L Optical path schematic diagram;

[0043] Figure 3 This is a schematic diagram of the optical path for simultaneously measuring vibration velocities along the horizontal and longitudinal directions.

[0044] Figure 4 To test the vibration velocity V in the X-axis direction in 1 X -T diagram.

[0045] Figure 5 To test the vibration velocity V in the Y-axis direction in section 1 Y -T diagram.

[0046] Figure 6 To test the longitudinal vibration velocity V in 1 L -T diagram.

[0047] Figure 7 To test the vibration velocity V in the X-axis direction of 2 X -T diagram.

[0048] Figure 8 To test the vibration velocity V in the Y-axis direction in section 2 Y -T diagram.

[0049] Figure 9 To test the longitudinal vibration velocity V in 2 L -T diagram.

[0050] The labels in the attached diagram have the following meanings: 1. Laser emitting device, 2. Right-angle reflector, 3. Coordinate measuring device, 4. Beam splitter, 5. Convex lens, 6. Laser rangefinder. Detailed Implementation

[0051] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0052] A method for monitoring seismic waves from blasting in underground caverns includes measuring the horizontal vibration velocity (V) of the cavern roof. S Measurement of longitudinal vibration velocity V L .

[0053] The method is as follows:

[0054] A right-angle reflector is suspended from the ceiling, with the reflector surface facing the floor of the room.

[0055] A laser emitting device is installed at the bottom of the chamber. The laser is emitted at an upward longitudinal angle. After being reflected twice by a right-angle mirror, the laser is reflected back downward longitudinally.

[0056] A. Measure the coordinates of the reflected laser before and after the blast using a coordinate measuring device to obtain the optical deflection displacement ΔS of the reflected laser before and after the blast. Combined with the time interval ΔT, and based on the velocity formula V... S =△S / 2△T(1), calculate the vibration velocity V of the seismic wave along the horizontal direction. S ,

[0057] That is, such as Figure 1 The optical path principle shown is that when the right-angle reflector moves horizontally a distance S1 along with the protected target (roof), the reflected laser point moves a distance of 2S1 on the coordinate measuring device, while the distance traveled by the laser from the transmitter to the coordinate measuring device is the same.

[0058] To facilitate simultaneous measurement of vibration velocity along the longitudinal direction, a beam splitter with a 45° tilt angle relative to the back-reflected laser is set along the optical path of the back-reflected laser, so that the beam splitter reflects part of the back-reflected laser as the first beam, which is then received by the coordinate measuring device.

[0059] The coordinate system is established as follows: the connection point between the right angle of the corner reflector and the roof of the chamber is taken as the center point, and any horizontal direction is taken as the X-axis direction to establish an XY horizontal coordinate system; preferably, the X-axis points in the blasting direction; after reflection by the beam splitter, the XY horizontal coordinate system can be folded into the X'-Y' coordinate system along the longitudinal direction of the coordinate measuring device, which is the coordinate detected by the coordinate measuring device.

[0060] Based on coordinates, the horizontal vibration velocity can be divided into vibration velocities V along the X-axis. X and vibration velocity V along the Y-axis Y ,

[0061] Among them, V X =△SX / 2△T (3)

[0062] V Y =△S Y / 2△T (4)

[0063] In the formula, △S X Let ΔS be the optical deflection displacement of the laser along the horizontal X-axis. Y This represents the optical deflection displacement of the laser beam along the horizontal Y-axis.

[0064] In actual measurement, the first beam can be sampled at a certain frequency to obtain a series of sampling data, and then:

[0065] V X =△S X / 2△T =(X i+1 -X i ) / 2 (T i+1 -T i (5)

[0066] V Y =△S Y / 2△T=(Y i+1 - Y i ) / 2 (T i+1 -T i (6)

[0067] In the formula, X i+1 X i The x-components of two adjacent coordinates in the sampling sequence; the y-components of the two coordinates. i+1 Y i T represents the y-component of two adjacent coordinates in the sampling sequence. i+1 T i These are two adjacent sampling times in the sampling sequence.

[0068] B. Along the optical path of the reflected laser, a convex lens is set after the beam splitter. The convex lens converges the second beam of the reflected laser refracted by the beam splitter. The second beam is received by the laser rangefinder and the optical path L is measured, thereby obtaining the optical path difference ΔL before and after the earthquake.

[0069] That is, such as Figure 2 The optical path principle shown is that when the right-angle reflector moves vertically a distance S2 along with the protected target (the ceiling), the position of the reflected laser point on the coordinate measuring device remains unchanged, while the distance the laser travels from the transmitter to the coordinate measuring device increases by 2S2.

[0070] Similarly, based on the velocity formula V L =△L / 2△T(2), to obtain the longitudinal vibration velocity V L .

[0071] Similarly, the laser rangefinder can sample the second beam at a certain frequency. Preferably, this sampling frequency is the same as and synchronized with the sampling frequency of the coordinate measuring device, thereby obtaining a series of sampling data, and then:

[0072] V L =△L / 2△T i = (L) i+1 - L i ) / 2 (T i+1 -T i (7)

[0073] In the formula, L i+1 L i The L component represents the adjacent samples in the sampling sequence.

[0074] C, such as Figure 3 As shown, when the right-angle reflector moves horizontally and vertically along with the protected target (roof): that is,

[0075] When the right-angle reflector moves horizontally a distance S1 along with the protected target, the laser beam is irradiated onto the coordinate measuring device through the beam splitter placed at 45°, and the light spot moves a distance of 2S1.

[0076] When the right-angle reflector moves vertically a distance S2 along with the protected target, the laser beam is irradiated onto the laser rangefinder via the beam splitter. The distance the laser travels from the laser emitter through the right-angle reflector, beam splitter, and convex lens to reach the laser rangefinder increases by 2S2.

[0077] The function of a convex lens is that when a right-angle mirror moves horizontally, the laser light reflected back from the radial angle will move left and right, but after passing through the convex lens, it will converge and be easier to receive.

[0078] Correspondingly, the applicable underground cavern blasting seismic wave monitoring device consists of a laser emitting device, a corner reflector, a beam splitter, a coordinate measuring device, a convex lens, and a laser rangefinder.

[0079] The system includes a corner reflector suspended from the ceiling; a laser emitting device located at the floor with the laser emission angle directly opposite the corner reflector along the longitudinal direction; a beam splitter positioned in the optical path of the reflected laser; a coordinate measuring device receiving and measuring the coordinates of the first beam of the reflected laser reflected by the beam splitter; a convex lens focusing the second beam of the reflected laser refracted by the beam splitter; and a laser rangefinder receiving the second beam and measuring the optical path based on the second beam. Example

[0080] The laser rangefinder used is the LH3000 dual-frequency laser interferometer manufactured by Raise Technology, with the following parameters: range: 40m; sampling: 100KHZ; accuracy: 16 micrometers.

[0081] The laser emitting device utilizes the laser from the laser rangefinder, eliminating the need for a separate laser emitting device.

[0082] The CB019MG-LX-X8G3 CMOS sensor manufactured by Aunion has the following parameters: measuring range: 15mm; sampling rate: 2000HZ; accuracy: 10 micrometers.

[0083] Taking a pumped storage power station culvert as an example (located in Jurong City, Jiangsu Province), the equipment culvert is 12 meters high, and the partition wall between it and the adjacent culvert is 20 meters thick. During the blasting excavation of the adjacent culvert, a traditional blasting vibration tester (Chengdu Taize blast-type blasting tester, placed on the top of the culvert) and this patented device were simultaneously deployed in the equipment culvert. To facilitate data comparison, the sampling frequency was uniformly set to 1kHz. The test results are as follows: Figure 4-6 As shown, Test 2 is as follows Figure 7-9 As shown, the X-axis points to the blasting location.

[0084] Data comparison shows that the results obtained by the present invention are in good agreement with those obtained by traditional measurement methods, proving that the present invention can be used for actual blasting vibration testing.

[0085] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the above embodiments do not limit the present invention in any way, and all technical solutions obtained by equivalent substitution or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A method for monitoring seismic waves during blasting in underground caverns, characterized in that, This includes measuring the vibration velocity of the ceiling of underground caverns along the horizontal and / or longitudinal directions, using the following method: A corner reflector is suspended on the ceiling of the chamber, and the reflected laser is emitted and received from the floor of the chamber. The optical deflection displacement ΔS, optical path difference ΔL, and time interval ΔT of the reflected laser before and after the earthquake are obtained. The corner mirror is a right-angle mirror. Using the velocity formula: The vibration velocity V along the horizontal direction is obtained from the optical polarization displacement ΔS. S =△S / 2△T (1) The longitudinal vibration velocity V is obtained from the optical path difference ΔL. L =△L / 2△T (2).

2. The method for monitoring seismic waves during blasting in underground caverns according to claim 1, characterized in that, With the point where the right angle of the corner reflector meets the ceiling as the center point and any horizontal direction as the X-axis, establish an XY horizontal coordinate system. The horizontal vibration velocity includes the vibration velocity V along the X-axis. X and vibration velocity V along the Y-axis Y , Among them, V X =△S X / 2△T (3) In Y =△S Y / 2△T (4) In the formula, △S X Let ΔS be the optical deflection displacement of the laser along the horizontal X-axis. Y This represents the optical deflection displacement of the laser beam along the horizontal Y-axis.

3. The method for monitoring seismic waves during blasting in underground caverns according to claim 1, characterized in that, The reflected laser beam is obtained by using a beam splitter to reflect the beam back, and then the coordinates of the first beam reflected by the beam splitter are obtained by using a coordinate measuring device; the optical deflection displacement ΔS of the reflected laser beam before and after the earthquake is obtained based on the coordinates.

4. The method for monitoring seismic waves during blasting in underground caverns according to claim 3, characterized in that, The beam splitter is tilted at an angle of 45° relative to the reflected laser.

5. The method for monitoring seismic waves during blasting in underground caverns according to claim 4, characterized in that, The reflected laser beam, passing through the second beam of the beam splitter, is focused by the convex lens and received by the laser rangefinder to measure the optical path difference ΔL between the reflected laser beam before and after the earthquake.

6. A seismic wave monitoring device for underground cavern blasting, characterized in that, The monitoring method described in claim 1 includes a laser emitting device, a corner reflector, a beam splitter, a coordinate measuring device, a convex lens, and a laser rangefinder; The corner reflector is suspended from the ceiling. The laser emitting device is located at the bottom of the chamber, and the laser emission angle is along the longitudinal diagonal reflector; The beam splitter is positioned along the optical path of the retro-reflected laser. The coordinate measuring device is used to receive and measure the coordinates of the first beam of the retro-echoed laser reflected by the beam splitter; The convex lens is used to converge the second beam of the retroreflected laser light that has passed through the beam splitter; The laser rangefinder is used to receive the second light speed and measure the optical path based on the second beam.

7. The underground cavern blasting seismic wave monitoring device according to claim 6, characterized in that, The coordinate measuring device samples the first beam at a certain frequency; V X =△S X / 2△T =(X i+1 -X i ) / 2(T i+1 -T i ) (5) V Y =△S Y / 2△T=(Y i+1 - Y i ) / 2(T i+1 -T i ) (6) In the formula, X i+1 X i The x-components of two adjacent coordinates in the sampling sequence; the y-components of the two coordinates. i+1 Y i T represents the y-component of two adjacent coordinates in the sampling sequence. i+1 T i These are two adjacent sampling times in the sampling sequence.

8. The underground cavern blasting seismic wave monitoring device according to claim 7, characterized in that, The laser rangefinder samples the second beam at the same frequency as the coordinate measuring device; V L =△L / 2△T i = (L i+1 - L i ) / 2(T i+1 -T i ) (7) In the formula, L i+1 L i The L component represents the adjacent samples in the sampling sequence.

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