Test method for detecting mining-induced stress change state monitoring effect based on strain image

Abstract

The invention provides a test method for detecting a mining-induced stress change state monitoring effect based on a strain image. The test method comprises the following steps: providing a rock mass sample; installing mining-induced stress monitoring equipment; checking the mining-induced stress monitoring equipment; loading a plurality of stresses to the rock mass sample; adjusting the stress state of the rock mass sample based on the current simulated working condition; strain data are obtained through the mining-induced stress monitoring device, the test stress of the rock mass sample is determined through the data processing system, and the measurement result for the mining-induced stress monitoring device is determined according to the comparison result of the test stress and the reference stress of the rock mass sample so as to judge the monitoring effect of the mining-induced stress monitoring device. The test method provided by the invention can be used for verifying the accuracy degree of the monitoring result of the mining-induced stress monitoring equipment on the rock mass sample indoors, determining whether the mining-induced stress monitoring equipment is suitable for detecting the corresponding rock mass sample or not, and contributing to improving the application accuracy and reliability of the mining-induced stress monitoring equipment under the actual working condition.

Description

Technical Field

[0001] The present application relates to the technical field of mining stress monitoring, and in particular to an experimental method for monitoring the effect of mining stress change state based on strain image detection. Background Art

[0002] In the mining of deep mineral resources, in order to ensure the safety and efficiency of mining operations, it is necessary to use mining stress monitoring equipment to measure the mining stress change characteristics of the rock mass; due to the complexity and diversity of rock mass structures, the reasonable deployment of special mining stress monitoring equipment is crucial to improving the monitoring effect of mining stress changes; in related technologies, due to the lack of verification methods for the monitoring effect of mining stress monitoring equipment, it is difficult to determine whether the mining stress monitoring equipment actually used can meet the measurement requirements of rock masses with different lithologies; if the accuracy of rock mass measurement by mining stress monitoring equipment is poor, it may affect the subsequent stress analysis and mining operations of the rock mass, increase the difficulty of mining, and even bring safety hazards. Summary of the invention

[0003] In view of this, the purpose of this application is to propose an experimental method for monitoring the state of mining stress changes based on strain image detection, so as to solve some or all of the technical problems mentioned above.

[0004] Based on the above purpose, the present application provides a test method for monitoring the state of mining stress changes based on strain image detection, the test method uses mining stress monitoring equipment, a data processing system and a pressure loading device; the mining stress monitoring equipment is connected to the data processing system, and the pressure loading device is connected to two first pressure plates, two second pressure plates and two third pressure plates in the first direction, the second direction and the third direction respectively; the two first pressure plates, the two second pressure plates and the two third pressure plates together enclose a loading space; wherein any one of the first direction, the second direction and the third direction is perpendicular to the other two directions;

[0005] The test method includes:

[0006] Providing a rock sample, wherein the rock sample has a preset borehole;

[0007] forming a speckle pattern on the inner wall surface of the preset borehole, installing the mining stress monitoring device in the preset borehole, and plugging the port of the preset borehole;

[0008] Assemble the rock sample in the loading space, and make the port of the preset borehole face any of the third pressure plates, and control the pressure loading device to calibrate the mining stress monitoring equipment;

[0009] Controlling the pressure loading device to drive the first pressing plate, the second pressing plate and the third pressing plate to load stress on the rock sample at a constant loading rate, until the stresses on the rock sample in the first direction, the second direction and the third direction reach a first preset stress, a second preset stress and a third preset stress, respectively, wherein the first preset stress, the second preset stress and the third preset stress decrease in sequence;

[0010] adjusting at least one of the first preset stress, the second preset stress and the third preset stress based on the current simulated working condition, acquiring strain data of the speckle pattern in the current simulated working condition through the mining stress monitoring device, and sending the strain data to a data processing system;

[0011] In response to determining that the data processing system has received the strain data, determining a test stress of the rock sample based on the strain data;

[0012] The measurement result of the mining stress monitoring equipment is determined based on the comparison result of the test stress and the reference stress of the rock sample at the same time, wherein the reference stress is the stress loaded by the pressure loading device to the rock sample at that time.

[0013] From the above, it can be seen that the test method for monitoring the effect of mining stress change state based on strain image detection provided by the present application can verify the accuracy of the monitoring results of the mining stress monitoring equipment on the rock samples, determine whether the mining stress monitoring equipment is suitable for detecting the corresponding rock samples, help the measurement effect of the mining stress monitoring equipment, and improve the accuracy and reliability of the mining stress monitoring equipment on rock monitoring under actual working conditions; in addition, the test method can verify the measurement effect of the mining stress monitoring equipment in an environment with limited space such as indoors, and is easy to operate and has good flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the present application or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0015] Figure 1 It is a flow chart of the test method for monitoring the state of mining stress changes based on strain image detection;

[0016] Figure 2 A flow chart of a method for adjusting a first preset stress, a second preset stress and a third preset stress based on different simulation working conditions;

[0017] Figures 3A-3G It is a schematic diagram of the force on the rock sample in different simulated working conditions;

[0018] Figure 4A-4C It is the stress curve diagram of rock specimen in different simulated working conditions;

[0019] Figure 5 Flow chart of the method for determining the comparison results of the test stress and the reference stress of the rock sample;

[0020] Figure 6 A flow chart of the method for determining whether the mining stress monitoring equipment meets the monitoring requirements;

[0021] Fig. 7A and Figure 7B Schematic diagram of mining stress monitoring equipment at different viewing angles;

[0022] Figure 7C It is a partial cross-sectional view of the mining stress monitoring equipment;

[0023] Figure 8 This is a block diagram of the connection between the mining stress monitoring equipment and the data processing system.

[0024] Description of reference numerals:

[0025] 100, mining stress monitoring equipment; 110, baffle; 111, housing; 120, column; 130, image acquisition module; 131, fixing plate; 132, camera module; 140, light source; 150, control module; 160, storage module; 170, power supply;

[0026] 200. Data processing system;

[0027] 300, pressure loading device; 301, first pressing plate; 302, second pressing plate; 303, third pressing plate; 400, rock sample; 401, preset drilling hole; 402, filling material. DETAILED DESCRIPTION

[0028] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0029] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be the usual meanings understood by people with ordinary skills in the field to which the present application belongs. The "first", "second" and similar words used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connecting" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0030] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0031] With the gradual depletion of shallow mineral resources, mineral resource mining activities have gradually advanced to a depth of 1,000 to 2,000 meters, which has brought huge challenges to mineral resource mining; due to the complex stress environment of deep rock masses, high ground pressure and frequent geological tectonic activities, the difficulty of mineral resource mining has increased significantly. Affected by the complex structure of the earth's interior and the continuous influence of gravity, the mining stress of deep rock masses is often in dynamic change; during mining operations, due to the combined effects of factors such as geological tectonic activities and mining disturbances, deep rock masses are difficult to maintain balance, which can easily cause a series of dynamic disasters such as mine collapse, rock wall rupture and impact ground pressure, thus posing a major security threat to the safety of deep mineral resource mining.

[0032] In order to meet the needs of deep mineral resource mining, it is necessary to accurately grasp the characteristics of mining force changes in deep rock masses. At present, technical personnel in this field have developed mining stress monitoring equipment such as pressure boxes, hollow inclusion sensors and microseismic monitoring systems to monitor the characteristics of mining stress changes in deep rock masses, so as to obtain and understand the stress changes in deep underground rock masses. Among them, non-contact digital image correlation technology has non-destructive detection, high resolution and the ability to capture subtle deformations. It can be used to analyze the image displacement field on the surface of an object to calculate the strain of the object. If non-contact digital image correlation technology is introduced into the mining stress monitoring equipment to measure the mining stress changes in deep rock masses, the monitoring accuracy and sensitivity of the mining stress changes in deep rock masses can be improved, and it is expected to provide reliable data support for monitoring the mining stress of deep rock masses.

[0033] However, no matter which type of mining stress monitoring equipment is used to measure deep rock masses, there will be errors in the mining stress monitoring equipment; specifically, firstly, due to the complex structure of the deep rock mass and the certain differences in the lithology of different rock masses, it is difficult to determine whether the deep rock mass is compatible with the mining stress monitoring equipment used to measure the deep rock mass; secondly, there is a lack of verification means for the monitoring effect of the mining stress monitoring equipment, and it is difficult to determine whether the mining stress monitoring equipment actually used meets the measurement requirements of rock masses with different lithologies; in addition, due to the difference between the stress data change state measured by the mining stress monitoring equipment and the actual stress state of the rock mass, if the accuracy of the mining stress monitoring equipment in measuring the rock mass is poor, it may affect the subsequent stress analysis and mining operations of the rock mass, increase the difficulty of mining, and even bring safety hazards.

[0034] Therefore, proposing an experimental method to detect the monitoring effect of mining stress change state is of great significance for ensuring the accuracy of monitoring equipment and improving the safety and efficiency of deep mineral resource development.

[0035] In view of this, the present application provides a test method for monitoring the state of mining stress changes based on strain image detection. The test method uses a mining stress monitoring device 100, a data processing system 200 and a pressure loading device 300; the mining stress monitoring device 100 is connected to the data processing system 200, and the pressure loading device 300 is connected to two first pressure plates 301, two second pressure plates 302 and two third pressure plates 303 in a first direction, a second direction and a third direction, respectively; the two first pressure plates 301, the two second pressure plates 302 and the two third pressure plates 303 together enclose a loading space; wherein any direction in the first direction, the second direction and the third direction is perpendicular to the other two directions;

[0036] The present application provides a test method for monitoring the state of mining stress changes based on strain image detection. The test method uses mining stress monitoring equipment 100, data processing system 200 and pressure loading device 300 to test the measurement accuracy of mining stress monitoring equipment 100. It can be carried out in a small space such as indoors, so it has good flexibility; Figure 1 and Figure 8 As shown, the mining stress monitoring device 100 is connected to the data processing system 200, and the mining stress monitoring device 100 obtains the strain data of the rock mass to be tested under different loads, and sends the obtained strain data to the data processing system 200 for analysis and processing by the data processing system 200;

[0037] The data processing system 200 can use equipment such as computers with data analysis, processing and calculation functions to receive the strain data sent by the mining stress monitoring equipment 100, and analyze, process and calculate the acquired strain data to obtain the mining stress change state of the rock mass to be tested; in addition, the data processing system 200 can be connected to the pressure loading device 300 to regulate the loading state of the pressure loading device 300.

[0038] As for the pressure loading device 300, the pressure loading device 300 can load stress to the rock mass to be tested in different directions; specifically, Figure 3A-3G As shown, the pressure loading device 300 can adopt a device with multi-directional loading function such as a true triaxial testing machine to assist the rock mass to be tested in simulating different stress conditions; more specifically, the pressure loading device 300 is connected to two first pressing plates 301, two second pressing plates 302 and two third pressing plates 303 in the first direction, the second direction and the third direction respectively; the two first pressing plates 301, the two second pressing plates 302 and the two third pressing plates 303 are jointly enclosed to form a loading space, and the loading space provides a test position for the rock mass to be tested, so that the pressure loading device 300 can be used to load stress on the rock mass to be tested in the first direction, the second direction and the third direction according to the test requirements;

[0039] For example, in order to improve the stability of the rock mass to be tested during the test, any two of the first direction, the second direction and the third direction are perpendicular to each other; for example, Figure 3A-3D As shown, the two first pressure plates 301 can be distributed in parallel up and down, that is, the first direction is vertical, which is equivalent to the Z-axis direction of the coordinate system, and the stress applied to the rock mass to be tested can be set to σ 1 The second pressure plate 302 can be parallel to the left and right, that is, the second direction is horizontal, which is equivalent to the X-axis direction of the coordinate system, and the stress loaded on the rock mass to be tested can be set to σ 2 The third pressure plate 303 can be parallel to the front and back distribution, at this time the third direction is the horizontal longitudinal direction, when the Y-axis direction in the coordinate system, the stress applied to the rock mass to be tested can be set to σ 3 .

[0040] like Figure 1 As shown, the experimental method for monitoring the state of mining stress changes based on strain image detection provided by the present application includes:

[0041] S100: providing a rock sample 400, wherein the rock sample 400 has a preset borehole 401;

[0042] In this step, the provided rock sample 400 can be used as the rock mass to be tested; wherein, the type and lithology of the rock sample 400 can be selected and determined according to the test requirements; more specifically, the rock sample 400 can adopt a cubic structure, and the rock sample 400 can be subjected to uniform force, which can reduce the interference of the shape of the rock sample 400 on the test results and reduce the complexity of the force on the rock sample 400; for example, the rock sample 400 can adopt a volume of 0.125m 3 -1m 3 If the test is carried out indoors, a rock sample with a side length of 0.8m and a volume of 0.512m 3 The cubic rock sample 400 is used as the standard rock sample 400.

[0043] For the rock sample 400 used in the test method for monitoring the effect of mining stress change state, the rock sample 400 can be prepared by using rock with a compressive strength in the range of 140MPa-200MPa under the original rock stress environment, to ensure that during the test, the rock sample 400 is subjected to a first preset stress in a first direction, which will not exceed 40%-50% of the original rock stress of the rock sample 400, thereby avoiding problems such as cracking or damage caused by excessive load on the rock sample 400, which affects the accuracy of the test; at the same time, it can also ensure that the stresses to which the rock sample 400 is subjected in different directions can induce obvious deformation of the speckle pattern, thereby obtaining strain data with obvious changes in the test.

[0044] It should be noted that a preset borehole 401 can be pre-drilled on one side of the rock sample 400 by a hole-drilling device such as a hole-drilling drill bit to provide an installation position and a strain measurement area for the mining stress monitoring device 100, so that the mining stress monitoring device 100 can obtain its strain data when mining stress occurs in the rock sample 400.

[0045] S200: forming a speckle pattern on the inner wall surface of the preset borehole 401, installing the mining stress monitoring device 100 in the preset borehole 401, and plugging the port of the preset borehole 401;

[0046] In this step, the strain state of the speckle pattern can be used to reflect the strain state of the rock sample 400, that is, the speckle pattern can be used as a target monitoring object using a stress monitoring device, and the stress change state of the rock mass to be tested can be inferred by monitoring the strain state of the speckle.

[0047] Exemplarily, the speckle pattern may be black and white speckle, which can improve the recognition effect of the speckle pattern; at the same time, the speckle pattern may be randomly distributed on the inner wall of the preset borehole 401 to ensure that its deformation can reflect the strain of the rock sample 400.

[0048] In a specific implementation, after obtaining a rock sample 400 with a preset borehole 401, a coating technology can be used to form a speckle pattern on the inner wall of the preset borehole 401 to provide a target monitoring object for the mining stress monitoring device 100; the mining stress monitoring device 100 is installed in the preset borehole 401 so that the mining stress monitoring device 100 can obtain strain data of the speckle pattern, and then the port of the preset borehole 401 is blocked to ensure the integrity of the rock sample 400, making it closer to the actual geological environment and rock layer structure of the rock mass, and avoiding the preset borehole 401 affecting the measurement result of the mining stress monitoring device 100.

[0049] S300: Assemble the rock sample 400 in the loading space, and make the port of the preset borehole 401 face any third pressure plate 303, and control the pressure loading device 300 to calibrate the mining stress monitoring equipment 100;

[0050] In this step, the pressure loading device 300 is used to drive the first pressure plate 301, the second pressure plate 302 and the third pressure plate 303; the first pressure plate 301 in the first direction, the second pressure plate 302 in the second direction and the third pressure plate 303 in the third direction respectively load stress to the rock sample 400, thereby simulating the stress state of the rock sample 400 under real working conditions.

[0051] In addition, in the test method provided in the present application, the stress σ applied by the third pressing plate 303 to the rock sample 400 in the third direction can be 3 As the minimum principal stress, that is, in a real environment, the minimum principal stress that the rock mass is subjected to in the horizontal direction is relatively small and has a small variation range. Therefore, by directing the port of the preset borehole 401 toward any third pressure plate 303, the interference degree of the preset borehole 401 on the stress state of the rock sample 400 can be reduced.

[0052] During specific implementation, before verifying the monitoring effect of the mining stress monitoring device 100, the rock sample 400 can be assembled in the loading space, and the port of the preset borehole 401 is directed toward any third pressure plate 303; after the rock sample 400 is assembled into the loading space, since there are gaps between the first pressure plate 301, the second pressure plate 302 and the third pressure plate 303 and the rock sample 400, the rock sample 400 is unevenly stressed at the beginning of being compressed, and the stress state and strain state of the rock sample 400 are quite different, which leads to a large error in the strain data obtained by the stress monitoring device; therefore, stress can be loaded on the rock sample 400 by the pressure loading device 300 to verify the monitoring state of the mining stress monitoring device 100 to ensure the consistency of the strain state of the rock sample 400 and the pressure loading device 300.

[0053] S400: Control the pressure loading device 300 to drive the first pressing plate 301, the second pressing plate 302 and the third pressing plate 303 to load stress to the rock sample 400 at a constant loading rate, until the stresses on the rock sample 400 in the first direction, the second direction and the third direction reach the first preset stress, the second preset stress and the third preset stress, respectively, wherein the first preset stress, the second preset stress and the third preset stress decrease in sequence;

[0054] In this step, if Figure 3A-3D The pressure loading device 300 drives the first pressure plate 301, the second pressure plate 302 and the third pressure plate 303 respectively at a constant loading rate. The constant loading speed can ensure the stability and predictability of the pressure loading process, which helps to reduce the impact of external variables on the monitoring of the mining stress change characteristics of the rock sample 400, so as to obtain test results with better consistency and reliability, while also preventing the rock sample 400 from being damaged, thereby improving the accuracy of the test and the safety of the operation.

[0055] The stress conditions of the rock mass in a real environment are described based on a three-dimensional coordinate system; affected by the structure of the rock mass and the gravity, the stress of most rock masses in the Z-axis direction is the largest and varies significantly, while the stress in the X-axis direction is the smallest and varies less; therefore, during the test, the stress received by the rock sample 400 in the first direction is the maximum principal stress, the stress received in the second direction is the intermediate principal stress, and the stress received in the third direction is the minimum principal stress; therefore, by making the stress received by the rock sample 400 in the first direction, the second direction and the third direction reach the first preset stress, the second preset stress and the third preset stress respectively, and making the first preset stress, the second preset stress and the third preset stress decrease successively, the stress condition of the rock sample 400 can be closer to the stress condition of the real rock mass, which is beneficial to improving the accuracy of the measurement accuracy verification of the mining stress monitoring equipment 100.

[0056] In a specific implementation, the pressure loading device 300 is controlled to drive the first pressing plate 301, the second pressing plate 302 and the third pressing plate 303 to move respectively, so that the first pressing plate 301, the second pressing plate 302 and the third pressing plate 303 move in the first direction to load the maximum principal stress σ on the rock sample 400. 1 , the rock mass specimen is loaded with a stress of 400 in the second direction 2 , and the stress σ is applied to the rock sample at 400 in the third direction. 3 , so that the rock sample 400 reaches the first preset stress, the second preset stress and the third preset stress respectively, thereby being close to the stable state of the rock in a real environment.

[0057] Exemplarily, when the pressure loading device 300 is used to load pressure on the rock sample 400, the first pressure plate 301, the second pressure plate 302 and the third pressure plate 303 can be driven respectively at a constant loading rate of 2 MPa / s to pressurize the rock sample 400 until the stresses on the rock sample 400 in the first direction, the second direction and the third direction reach 60 MPa, 40 MPa and 20 MPa respectively, so as to simulate the stable state of the rock in a real environment.

[0058] S500: adjusting at least one of the first preset stress, the second preset stress and the third preset stress based on the current simulated working condition, acquiring strain data of the speckle pattern in the current simulated working condition through the mining stress monitoring device 100, and sending the strain data to the data processing system 200;

[0059] In this step, in a real environment, there are large differences in the stress conditions of the rock mass under different working conditions; by adjusting the first preset stress, the second preset stress and the third preset stress, the stress conditions of the rock mass sample 400 under different working conditions can be simulated, so that the mining stress monitoring device 100 can obtain the strain data of the rock mass under different working conditions, so as to improve the accuracy of the verification of the mining stress monitoring device 100;

[0060] It should be noted that, since the rock sample 400 reflects the change state of its mining stress through the speckle pattern in the preset borehole 401, the strain data acquired by the mining stress monitoring device 100 may be the strain data of the speckle pattern.

[0061] In specific implementation, since the stress state of the rock sample 400 in different directions changes under the actual working condition, the actual working condition can be simulated by changing the stress in different directions loaded on the rock sample 400 during the test; more specifically, the working condition to be simulated can be determined in the preset simulated working condition, and the simulated working condition can be used as the current simulated working condition, and then at least one of the first preset stress, the second preset stress and the third preset stress can be adjusted according to the stress adjustment requirements in the current simulated working condition, so as to change the mining stress state of the rock sample 400 to make it fit the actual working condition; at this time, the strain data of the speckle pattern can be obtained in real time in the current simulated working condition through the mining stress monitoring device 100, and the strain data can be synchronously sent to the data processing system 200 through the mining stress monitoring device 100 for analysis and processing by the data processing system 200, which is helpful to determine whether the mining stress monitoring device 100 can accurately measure the monitoring effect of the rock sample 400 under the current simulated working condition, thereby improving the verification effect of the mining stress monitoring device 100.

[0062] S600: In response to determining that the data processing system 200 receives the strain data, determining the test stress of the rock sample 400 according to the strain data;

[0063] In this step, the test stress is the stress value determined by the data processing system 200 according to the received strain data and elastic mechanics theory; specifically, the strain data can be calculated by the following elastic mechanics formula, and the specific calculation formula is as follows:

[0064] E[Δε 1 Δε 2 Δε 3 Δε 4 ... Δε 12 ] T =M×[σ' 3 σ' 2 σ' 1 τ 23 τ 12 τ 13 ] T

[0065] Wherein, E represents the elastic modulus of the rock sample, the matrix M is a coefficient matrix for solving stress components according to the directions of the strain data (i.e., the strain image highlighted by speckle) obtained by the mining stress monitoring device 100, and ε n is the initial strain before release, ε' n is the final strain after release, Δε n =ε' n -ε n Based on this, the strain data of three positions are obtained by using stress monitoring equipment, and the strain data of each position point may include four different directions (for example, each set of strain data comes from the strain images in the directions of 0°, 45°, 90° and 135° respectively), that is, the initial strain data of the rock sample 400 in 12 directions are ε 1 , ε 2 , ε 3 , ε 4 , ε 5 , ε 6 , ε 7 , ε 8 , and ε 9 , ε 10 , ε 11 , ε 12 The final release strain data in the above 12 directions are ε' 1 , ε' 2 , ε' 3 , ε' 4 , ε' 5 , ε' 6 , ε' 7 , ε'8 , and ε' 9 , ε' 10 , ε' 11 , ε' 12 ; Among them, ε 1 For example:

[0066] Δε 1 =ε' 1 -ε 1 ;

[0067] The six stress components are σ' 3 ,σ' 2 ,σ' 1 , τ 23 , τ 21 , τ 13 ; Among them, σ 3 , σ 2 , σ 1 Increasing in sequence, namely, the minimum stress, the intermediate principal stress and the maximum principal stress; τ 12 represents the shear stress acting on the front and rear sides of the rock sample 400 and along the Y-axis direction, τ 23 represents the shear stress acting on the upper and lower sides of the rock sample 400 and along the Z axis, τ 13 It represents the shear stress acting on the rock sample 400 degrees on both sides and along the X-axis direction. The calculated σ' 3 ,σ' 2 ,σ' 1 The stresses exerted on the test rock mass in three directions are obtained by the mining stress monitoring device and used as the test stress of the rock sample 400. By verifying the test stress of the rock sample 400, it can be determined whether the monitoring effect of the mining stress monitoring device 100 is accurate.

[0068] S700: Determine the measurement result of the mining stress monitoring device 100 based on the comparison result of the test stress at the same time and the reference stress of the rock sample 400, wherein the reference stress is the stress loaded by the pressure loading device 300 to the rock sample 400 at that time.

[0069] In this step, the reference stress is the stress loaded by the pressure loading device 300 to the rock sample 400 within a certain moment, that is, the stress loaded on the surface of the rock sample 400 by the pressure loading device 300; in specific implementation, after obtaining the test stress of the rock sample 400 determined based on the strain data; the stress loaded to the rock sample 400 in different directions by the pressure loading device 300 through the first pressure plate 301, the second pressure plate 302 and the third pressure plate 303 at the same moment can be retrieved, and the stress loaded to the rock sample 400 at this moment is used as the reference stress.

[0070] Specifically, by comparing the test stress of the rock sample 400 with the reference stress of the rock sample 400, a corresponding comparison result can be obtained; then, based on the comparison result, it can be determined whether the monitoring of the rock sample 400 by the mining stress monitoring equipment 100 is accurate and whether it is suitable for monitoring this type of rock mass; more specifically, if the comparison result shows that the difference between the test stress of the rock sample 400 and the reference stress of the rock sample 400 is large, then the accuracy of the measurement of the rock sample 400 by the mining stress monitoring equipment 100 is low, and it is not suitable for monitoring this type of rock mass; conversely, if the comparison result shows that the difference between the test stress of the rock sample 400 and the reference stress of the rock sample 400 is small, then the accuracy of the measurement of the rock sample 400 by the mining stress monitoring equipment 100 is high, and it is suitable for monitoring this type of rock mass.

[0071] In summary, the test method for monitoring the effect of mining stress change state based on strain image detection provided in the present application can verify the accuracy of the monitoring results of the mining stress monitoring equipment 100 on the rock sample 400, and determine whether the mining stress monitoring equipment 100 is suitable for detecting the corresponding rock sample 400, which is helpful to the measurement effect of the mining stress monitoring equipment 100, and improves the accuracy and reliability of the mining stress monitoring equipment 100 on rock monitoring under actual working conditions; in addition, the test method can verify the measurement effect of the mining stress monitoring equipment 100 in an environment with limited space such as indoors, and is easy to operate and has good flexibility.

[0072] In some embodiments, S500 is further described; Figure 2-4C As shown, in S500, adjusting at least one of the first preset stress, the second preset stress, and the third preset stress based on the current simulation working condition includes:

[0073] S510: Determine the type of the current simulation condition;

[0074] In this embodiment, the stress loaded on the rock sample 400 by the simulated working condition can be close to the stress condition of the rock in the corresponding real working condition, so as to ensure that the rock sample 400 can provide the mining stress change scene similar to the real environment for the mining stress monitoring equipment 100, and can determine whether the mining stress monitoring equipment 100 can accurately measure the mining stress change under the simulated working condition, so as to judge whether the mining stress monitoring equipment 100 has good measurement accuracy; in specific implementation, multiple simulated working conditions can be set in advance, and then the simulated working condition to be implemented can be determined as the current simulated working condition for monitoring by the mining stress monitoring equipment 100.

[0075] S520: In response to determining that the current simulation condition is a stress change condition simulating the original rock stress field, controlling the pressure loading device 300 to drive the first pressing plate 301 to load stress to the rock sample 400 at a preset loading rate until the stress on the rock sample 400 in the first direction reaches a first target stress, wherein the first target stress is greater than the first preset stress;

[0076] In this step, the rock mass in the original rock stress field is affected by gravity and geological changes, and the rock mass tends to be stable after the stress in the first direction increases; therefore, Figure 3E As shown, when it is determined that the current simulation condition is a stress change condition simulating the original rock stress field, in order to make the stress condition of the rock sample 400 close to the stress change condition of the original rock stress field, the pressure loading device 300 can be controlled to drive the first pressure plate 301 to load stress on the rock sample 400 along the first direction according to the preset loading rate, so that the stress of the rock sample 400 in the first direction increases at a uniform rate and then increases steadily, so as to reserve enough time for the mining stress monitoring equipment 100 to monitor the strain state of the rock sample 400, and until the stress received by the rock sample 400 in the first direction is loaded to a first target stress greater than the first preset stress, so that the stress change condition simulating the original rock stress field is closer to the real original rock stress field, so as to provide a more realistic monitoring environment for the mining stress monitoring equipment 100, thereby making the test results more accurate.

[0077] For example, Figure 3E and 4A As shown, when the rock sample 400 is subjected to the first preset stress, the second preset stress and the third preset stress are 60 MPa, 40 MPa and 20 MPa respectively, in order to make the stress condition of the rock sample 400 closer to the stress change of the original rock stress field, the stress change condition of the original rock stress field can be simulated, and the pressure loading device 300 is controlled to drive the first pressure plate 301 to load stress to the rock sample 400 at a preset loading rate of 2 MPa / s until the stress to which the rock sample 400 is subjected in the first direction is loaded to 80 MPa, so that the stress change condition of the simulated original rock stress field is closer to the stress change condition of the real original rock stress field.

[0078] Since the first preset stress to which the rock sample 400 is subjected is 40%-50% of the compressive strength of the rock mass under the original rock stress environment to which the rock sample 400 is subjected, a rock mass with an original rock stress of not less than 160MPa and not more than 200MPa can be used to form the test rock sample 400.

[0079] S530: In response to determining that the current simulated working condition is a stress change working condition simulating tunnel excavation unloading, controlling the pressure loading device 300 to drive the second pressing plate 302 to remove stress from the rock sample 400 at a preset unloading rate until the stress on the rock sample 400 in the second direction is zero;

[0080] In this step, when the rock mass is in the tunnel excavation unloading state, due to the lack of intermediate force inside the rock mass, the stress inside the rock mass in the second direction gradually decreases and gradually tends to zero; therefore, Figure 3F As shown, when it is determined that the current simulated working condition is a stress change working condition simulating tunnel excavation unloading, in order to make the stress condition of the rock sample 400 close to the stress change working condition of tunnel excavation unloading, the pressure loading device 300 can be controlled to drive the second pressure plate 302 to remove the stress from the rock sample 400 according to the preset unloading rate, so that the stress on the rock sample 400 in the second direction is steadily reduced, so as to reserve sufficient time for the mining stress monitoring equipment 100 to monitor the strain state of the rock sample 400 until the stress on the rock sample 400 in the second direction is zero, so that the stress change working condition simulating tunnel excavation unloading is closer to the stress field during the real tunnel excavation unloading, so as to provide a more realistic monitoring environment for the mining stress monitoring equipment 100, thereby making the test results more accurate.

[0081] It should be noted that if Figure 4A and 4B As shown, since the rock mass is in a stable state during tunnel excavation, that is, it switches from the final state of the stress change condition of the original rock stress field to the initial state of the stress change condition of tunnel excavation unloading, the first preset stress of the rock mass in the first direction under the stress change condition of the original rock stress field is less than the first preset stress of the rock mass in the first direction under the stress change condition of tunnel excavation unloading; for example, the first preset stress of the rock mass in the first direction under the stress change condition simulating the original rock stress field is 60MPa, and the first preset stress of the rock mass in the first direction under the stress change condition simulating the tunnel excavation unloading is 80MPa.

[0082] For example, Figure 3F and 4B As shown, when the rock sample 400 is subjected to the first preset stress, the second preset stress and the third preset stress are 80 MPa, 40 MPa and 20 MPa respectively, in order to make the stress condition of the rock sample 400 closer to the stress change of tunnel excavation unloading, the stress change condition of tunnel excavation unloading can be simulated, and the pressure loading device 300 is controlled to drive the second pressure plate 302 to remove the stress from the rock sample 400 at a preset unloading rate of 5 MPa / s until the stress on the rock sample 400 in the second direction is reduced to 0, so that the stress change condition of the simulated tunnel excavation unloading is closer to the stress change condition of the real tunnel excavation unloading.

[0083] Since the first preset stress to which the rock sample 400 is subjected is 40%-50% of the compressive strength to which the rock sample 400 is subjected under the original rock stress environment, the rock sample 400 used in this test can be formed by using a rock mass with a compressive strength of not less than 150MPa and not more than 200MPa under the original rock stress environment.

[0084] S540: In response to determining that the current simulated working condition is a stress change working condition simulating a blasting scenario, a disturbance device is provided, and a first preset stress is adjusted according to a preset frequency and a preset amplitude by controlling the disturbance device.

[0085] In this step, after the tunnel excavation is completed, mining can be carried out by blasting or other means. At this time, under the influence of blasting, the stress of the rock mass in the first direction will fluctuate periodically; therefore, Figure 3G As shown, when it is determined that the current simulated working condition is a stress change working condition of a simulated blasting scene, in order to make the stress condition of the rock sample 400 close to the stress change working condition of the blasting scene, a disturbance device can be provided. The disturbance device is used to adjust the first preset stress according to a preset frequency and a preset amplitude, that is, to adjust the force magnitude of the rock sample 400 in the first direction, so that the stress change working condition of the simulated blasting scene is closer to the stress field of the actual blasting scene, so as to provide a more realistic monitoring environment for the mining stress monitoring equipment 100, thereby making the test results more accurate.

[0086] It should be noted that if Figure 4B and 4C As shown, since rock blasting usually occurs after the tunnel excavation is completed, that is, the final state of the stress change condition of the tunnel excavation unloading is switched to the initial state of the stress change condition of the simulated blasting scene, the first preset stress of the rock in the first direction under the stress change condition of the simulated blasting scene is the same as the first preset stress of the rock in the first direction under the stress change condition of the tunnel excavation unloading; for example, the first preset stress of the rock in the first direction under the stress change condition of the simulated tunnel excavation unloading is 80MPa, and the first preset stress in the first direction under the stress change condition of the blasting scene is also 80MPa.

[0087] For example, Figure 3G and 4CAs shown, when the rock sample 400 switches from the stress change condition of simulated tunnel excavation unloading to the stress change condition of simulated blasting scene, the rock sample 400 is subjected to the first preset stress, the second preset stress and the third preset stress of 80MPa, 40MPa (since the second preset stress in the second direction will not cause the stress change condition of the simulated blasting scene, the second preset stress can be 0MPa or 40MPa) and 20MPa respectively. In order to make the stress condition of the rock sample 400 closer to the stress change condition of the blasting scene, the stress change condition of the blasting scene can be simulated, and the pressure loading device 300 is controlled to adjust the first preset stress at a frequency of 10Hz and an amplitude of 15MPa, that is, the first preset stress in this state is set as a variable stress, and during the disturbance process, the first preset stress of the rock sample 400 in the first direction takes a value range of 80MPa-95MPa, so that the stress change condition of simulated tunnel excavation unloading is closer to the stress change condition of real tunnel excavation unloading.

[0088] Since the first preset stress to which the rock sample 400 is subjected is 40%-50% of the compressive strength to which the rock sample 400 is subjected under the original rock stress environment, the rock sample 400 used in this test can be formed by using a rock having a compressive strength of not less than 160 MPa and not more than 240 MPa under the original rock stress environment.

[0089] In summary, the test method for monitoring the effect of mining stress change state in this application can use a rock sample 400 with a compressive strength of 160MPa-200MPa under the original rock stress environment, which can ensure that the rock sample 400 will not be damaged during the test, and the strain data obtained has a high accuracy, which will not be repeated here.

[0090] In some embodiments, the port of the preset borehole 401 is blocked, including: using a filler 402 made of the same material as the rock sample 400 to block the port of the preset borehole 401 , and drying the filler 402 .

[0091] In this step, by plugging the preset borehole 401 of the rock sample 400, the integrity of the rock sample 400 can be guaranteed and the interference of the preset borehole 401 on the test results can be reduced; Figure 3C As shown, the end of the preset borehole 401 is sealed by using a filler 402 made of the same material as the rock sample 400, for example, using mortar made of the same material as the rock sample to seal it, ensuring that the sealed sample has the same physical and mechanical parameters as the original rock, thereby ensuring the accuracy of the test results; in addition, after the sealing is completed, the filling effect of the filler 402 can be improved by drying the filler 402, thereby avoiding the filler from falling off or breaking during the test and causing interference with the test results.

[0092] In some embodiments, the pressure loading device 300 is controlled to calibrate the mining stress monitoring equipment 100, including: controlling the pressure loading device 300 to drive the first pressure plate 301, the second pressure plate 302 and the third pressure plate 303 to load stress to the rock sample 400 respectively, until the stress on the rock sample 400 in the first direction, the second direction and the third direction reaches a preset calibration stress.

[0093] In this step, before stress is applied to the rock sample 400, due to the gaps between the first pressure plate 301, the second pressure plate 302, and the third pressure plate 303 and the rock sample 400, the strain data measured by the mining stress monitoring device cannot reflect the real stress change characteristics of the rock sample 400 at the initial stage of loading the rock sample 400; therefore, at the beginning of the test, the mining stress monitoring device 100 needs to be calibrated to ensure that the stress applied to the rock sample 400 by the pressure loading device 300 is consistent with the strain of the rock sample 400; in specific implementation, the pressure loading device 300 can be controlled to drive the first pressure plate 301, the second pressure plate 302, and the third pressure plate 303 to drive the rock sample 400 to move forward and backward, respectively. 302 and the third pressure plate 303 load stress to the rock sample 400 until the stress on the rock sample 400 in the first direction, the second direction and the third direction reaches the preset verification stress, so that the first pressure plate 301, the second pressure plate 302 and the third pressure plate 303 can be fully pressed against the surface of the rock sample 400, and ensure that when the pressure loading device 300 is used to load stress on the rock sample 400 later, the stress applied to the rock sample 400 by the pressure loading device 300 is consistent with the strain of the rock sample 400, thereby reducing the impact of the error generated during the loading process of the pressure loading device 300 on the detection result of the mining stress monitoring equipment 100.

[0094] Exemplarily, when calibrating the mining stress monitoring equipment 100, the pressure loading device 300 is controlled to drive the first pressure plate 301, the second pressure plate 302 and the third pressure plate 303 to move toward the direction close to the rock sample 400 in the first direction, the second direction and the third direction respectively, so that the first pressure plate 301, the second pressure plate 302 and the third pressure plate 303 contact the surface of the rock sample and load stress thereon, until the stress in the first direction, the second direction and the third direction of the rock sample 400 is loaded to 0.5MPa, that is, loaded to the preset calibration stress, so that the stress applied to the rock sample 400 by the pressure loading device 300 is consistent with the strain condition of the rock sample 400.

[0095] In some embodiments, after the stress on the rock sample 400 in the first direction, the second direction and the third direction reaches a preset verification stress, it also includes: in response to determining that the data processing system 200 receives verification data acquired by the mining stress monitoring equipment 100 during the verification process, controlling the data processing system 200 to initialize the verification data.

[0096] In this embodiment, when the mining stress monitoring device 100 is calibrated, the mining stress monitoring device 100 needs to remain in an open state to determine whether it can collect strain data of the speckle pattern in the preset borehole 401; therefore, the mining stress monitoring device 100 can obtain strain data with poor accuracy and inconsistent with the mining stress change characteristics of the rock sample 400 during the calibration process, which is the calibration data, and send it to the data processing system 200 via a wireless network or Bluetooth or other communication connection method. At this time, the data processing system 200 can be controlled to initialize the calibration data, thereby eliminating the interference of the calibration process and the calibration data on the test results.

[0097] In some embodiments, S700 is further described; Figure 5 As shown, in S700, the test stress includes a plurality of sub-test stresses, the reference stress includes a plurality of sub-reference stresses, and each sub-test stress corresponds to a sub-reference stress; according to the comparison result of the test stress at the same time and the reference stress of the rock sample 400, the measurement result of the mining stress monitoring device 100 is determined, including:

[0098] S710: Determine a plurality of sub-stress deviation values ​​according to a plurality of sub-test stresses and a plurality of corresponding sub-reference stresses;

[0099] S720: Compare the multiple sub-stress deviation values ​​with the preset deviation thresholds respectively, and determine whether the measurement result of the mining stress monitoring device 100 at the current moment meets the monitoring requirements based on the comparison results.

[0100] Specifically, the data processing system 200 can obtain the strain data obtained by the mining stress monitoring device 100 to calculate the test stress of the rock sample 400, and then determine the monitoring effect of the mining stress monitoring device 100 through the comparison result based on the test stress at the same time and the reference stress of the rock sample 400; wherein, since the test stress includes a plurality of sub-test stresses in different directions, namely, σ' in the first direction, the second direction and the third direction 1 ,σ' 2 ,σ' 3, which can be regarded as three sub-test stresses. At the same time, the pressure loading device 300 applies σ to the rock sample 400 in the first direction, the second direction and the third direction respectively through the first pressure plate 301, the second pressure plate 302 and the third pressure plate 303. 1 , σ 2 , σ 3 , can be regarded as three sub-reference pressures. According to the sub-test stress and the corresponding sub-reference stress, multiple sub-stress deviation values ​​can be determined, namely:

[0101] |Δσ 1 |=σ' 1 -σ 1 ;

[0102] |Δσ 2 |=σ' 2 -σ 2 ;

[0103] |Δσ 2 |=σ' 3 -σ 3 ;

[0104] Among them, |Δσ 1 |,|Δσ 2 |,|Δσ 2 |represent the stress deviation values ​​in the first direction, the second direction and the third direction respectively, and the accuracy of the mining stress monitoring device 100 in monitoring the mining stress change characteristics of the rock sample 400 at this moment can be determined according to the stress deviation values; that is, the multiple sub-stress deviation values ​​are respectively compared with the preset deviation threshold value to determine whether the difference between the stress deviation value and the preset deviation threshold value is too large, and then based on the comparison result, it is judged whether the measurement result of the mining stress monitoring device 100 at the current moment meets the monitoring requirements; more specifically, if the deviations between the multiple sub-stress deviation values ​​and the preset deviation threshold value are small, then the measurement result error of the mining stress monitoring device 100 at the current moment is small and meets the monitoring requirements; if there is a stress deviation value with a large deviation from the preset deviation threshold value among the multiple sub-stress deviation values, then the measurement result error of the mining stress monitoring device 100 at the current moment is large and does not meet the monitoring requirements;

[0105] As an alternative embodiment, the data processing system 200 can be used to draw a test stress and time graph of the rock sample 400 in the same time period, as well as a baseline stress and time graph of the rock sample 400, and compare the two graphs and calculate the mean square error. If the mean square error of the two graphs is less than or equal to the preset error value, it indicates that the measurement result error of the mining stress monitoring equipment 100 at the current moment is small and meets the monitoring requirements; if the mean square error of the two graphs is greater than the preset error value, it indicates that the measurement result error of the mining stress monitoring equipment 100 at the current moment is large and does not meet the monitoring requirements.

[0106] In some embodiments, S720 is further described; Figure 6 As shown, in S720, the plurality of sub-stress deviation values ​​are respectively compared with the preset deviation thresholds, and based on the comparison results, it is determined whether the measurement result of the mining stress monitoring device 100 at the current moment meets the monitoring requirements, including:

[0107] S721: In response to determining that the plurality of sub-stress deviation values ​​are all less than or equal to the preset deviation threshold, the measurement result of the mining stress monitoring device 100 at the current moment meets the monitoring requirement;

[0108] In this step, the preset deviation value is used to determine whether the error between the sub-test stress and the sub-reference stress at the current moment is too large; in specific implementation, when it is determined that multiple sub-stress deviation values ​​are all less than or equal to the preset deviation threshold, it indicates that the measurement result error of the mining stress monitoring equipment 100 at the current moment is small. At this time, the measurement result of the mining stress monitoring equipment 100 at the current moment meets the monitoring requirements and is also suitable for monitoring this type of rock.

[0109] S722: In response to determining that at least one of the multiple sub-stress deviation values ​​is greater than a preset deviation threshold, the measurement result of the mining stress monitoring device 100 at the current moment does not meet the monitoring requirements.

[0110] In this step, during the specific implementation, when it is determined that multiple sub-stress deviation values ​​are all greater than the preset deviation threshold, it indicates that the measurement result error of the mining stress monitoring equipment 100 at the current moment is large. At this time, the measurement result of the mining stress monitoring equipment 100 at the current moment does not meet the monitoring requirements, and is therefore not suitable for monitoring this type of rock.

[0111] It should be noted that in order to improve the accuracy of verification of the mining stress monitoring equipment 100, the sub-stress deviation values ​​at different times can be determined through the data processing system 200 to fully verify the monitoring situation of the mining stress monitoring equipment 100 within the time period, which can further improve the accuracy of verification of the measurement effect of the mining stress monitoring equipment 100.

[0112] In some embodiments, the dynamic stress monitoring device 100 includes two baffles 110, a column 120, at least three image acquisition modules 130, a light source 140, a control module 150, a storage module 160 and a power supply 170; the two baffles 110 are fixedly connected to the opposite ends of the column 120 respectively; the column 120 is a regular triangular prism, and three installation side surfaces connected in pairs are respectively provided along its circumference, and each installation side surface is connected to at least one group of image acquisition modules 130; the light source 140 is arranged on the side of the baffle 110 close to the column 120; a shell is provided on the side of one of the two baffles 110 away from the column 120, and the control module 150, the storage module 160 and the power supply 170 are all arranged in the shell 111; the control module 150 is respectively connected to the at least three image acquisition modules 130 and the light source 140; the power supply 170 is electrically connected to the at least three image acquisition modules 130, the light source 140 and the storage module 160 respectively.

[0113] Among them, the present application provides a mining stress monitoring device 100 that can improve the effect of obtaining mining stress images of a rock sample 400; during the test process, the mining stress monitoring device 100 is installed in a preset borehole 401 of the rock sample 400; more specifically, as Figure 3C , Figure 7A-7C and Figure 8 As shown, the mining stress monitoring device 100 includes two baffles 110, a column 120, three images, a light source 140, a control module 150, a storage module 160 and a power supply 170; based on the installation method of the mining stress monitoring device, one of the two baffles 110 is arranged close to the port of the preset borehole 401 to block the filler 402 that blocks the preset borehole 401; the other is arranged away from the port of the preset borehole 401, and a shell 111 is arranged on the side of the baffle 110 away from the column 120 to accommodate electronic components such as the control module 150, the storage module 160 and the power supply 170 in the mining stress monitoring device 100 and form effective protection.

[0114] The baffles 110 are fixedly connected to the opposite ends of the column 120 respectively. The column 120 is a regular triangular prism, and three installation side surfaces connected in pairs are respectively arranged along its circumference. Each installation side surface is connected to at least one group of image acquisition modules 130 to provide an installation position for the image acquisition modules 130, so that each installation side surface is provided with at least one group of image acquisition modules 130, and the image acquisition modules 130 are used to collect the strain data of the speckle pattern and send it to the data processing system 200; at least three image acquisition modules 130 are arranged in sequence along the extension direction of the column 120, so that the interference between adjacent image acquisition modules 130 can be avoided.

[0115] The light source 140 is disposed on a side of the baffle 110 close to the column 120 , and is used to provide light for the image acquisition module 130 , thereby ensuring the acquisition effect of the speckle pattern strain data and improving the clarity of the imaging.

[0116] For the light source 140, Figure 7A-7C As shown, by arranging a plurality of light sources 140 on the baffle 110 and making the plurality of light sources 140 evenly distributed along the circumference of the surface of the baffle 110, a good shooting environment can be formed in the preset borehole 401, which is beneficial to improving the imaging effect of the image acquisition module 130 and improving the accuracy of strain data measurement; illustratively, the light source 140 can adopt an LED light source 140, which generates uniform light, has a small volume and low energy consumption, and will not be described in detail here.

[0117] More specifically, the column 120 is a triangular prism, which allows the multiple light sources 140 to be evenly distributed along the circumference of the baffle 110, so that each light source 140 is arranged corresponding to an edge of the column 120, so that the edges of the column 120 can be avoided from blocking the light emitted by the light source 140, and the formation of a dark shadow area in the preset borehole 401 can be avoided, which is beneficial to improving the shooting effect of the speckle pattern; in addition, the design can also improve the uniformity of the light intensity in the preset borehole 401, and ensure that the strain data obtained by adjacent image acquisition modules 130 can be correlated with each other, which is beneficial to improving the accuracy of the obtained strain data.

[0118] The control module 150 can be arranged in the shell 111, and the shell 111 accommodates and protects the control module 150; the control module 150 is electrically connected to the three images, the light source 140 and the data processing system 200 respectively, and can be used to control the switching state of the image acquisition module 130 and the light source 140; at the same time, it can also adjust the application parameters of the image acquisition module 130 and the light source 140.

[0119] It should be noted that since the mining stress monitoring device 100 is located inside the rock sample 400, in order to achieve stable transmission of strain data and control instructions, the control module 150 can establish a connection with the data processing system 200 using a wireless network or Bluetooth, which will not be repeated here.

[0120] The image acquisition module 130 is electrically connected to the image acquisition module 130, that is, the image acquisition module 130 can send the strain data of the acquired speckle image to the storage module 160, and use its storage function to store and back up the strain data, which can avoid the image loss caused by the poor signal inside the preset drilling hole 401, and facilitate later retrieval and viewing.

[0121] The power supply 170 is electrically connected to the light source 140, the three images, the storage module 160 and the control module 150, respectively, to provide electrical energy to the light source 140, the three images, the storage module 160 and the control module 150, so as to drive each part to operate normally; illustratively, the power supply 170 mentioned above can adopt secondary batteries such as lithium batteries, which have good energy storage effect, large capacity and can be recycled, and will not be repeated here.

[0122] Therefore, compared with the original rock monitoring equipment, the mining stress monitoring equipment 100 provided in the present application is small in size and has good supporting effect. It can provide a good image information acquisition environment in a narrow space, improve the clarity of the acquired image during the imaging process, and is beneficial to improving its accuracy in monitoring the mining stress change characteristics of the rock sample 400, so that it can be applied to various types of rock.

[0123] In some embodiments, each image acquisition module 130 includes two fixing plates 131 and four camera modules 132; the two fixing plates 131 are respectively fixedly connected to the same mounting side, the extension direction of the two fixing plates 131 is an angle of 45°, and the extension direction of one of the two is perpendicular to the extension direction of the column 120; each fixing plate 131 is provided with two camera modules 132, the two camera modules 132 and the column 120 are located on the same side of the fixing plate 131, and the two camera modules 132 are located on opposite sides of the column 120 and are symmetrically arranged.

[0124] Among them, the image acquisition module 130 disposed on the side of the column 120 can collect the strain data of the speckle pattern on the inner wall of the preset drilling hole 401; Figure 7A-7C As shown, since strain measurement is adopted to calculate the changes in the morphology, displacement and strain data of the rock sample 400 in the full field of view in three-dimensional space by capturing the movement of the speckle pattern image features at the pixel level; in order to ensure that the strain data of the speckle pattern can be accurately captured, a column 120 in the shape of a regular triangular prism can be used, and an image acquisition module 130 is respectively arranged on each installation side thereof, wherein each image acquisition module 130 includes two fixing plates 131 whose extension directions are 45°, and the extension direction of one of them is also perpendicular to the extension direction of the column 120, and two camera modules 132 are arranged on the same side of the fixing plate 131 as the column 120, so that the two camera modules 132 are respectively located on opposite sides of the column 120, so that they are symmetrically distributed relative to the central area of ​​the fixing plate 131.

[0125] For example, since the rock sample 400 has maximum principal stress, intermediate principal stress and minimum principal stress and different azimuths during the test, in addition to vertical and horizontal strains, it is necessary to add strains in two more directions, that is, each image acquisition module 130 can obtain strain data in four different directions. Therefore, the position relationship of the two camera modules 132 on the same fixed plate 131 can be set (that is, the two camera modules are arranged symmetrically relative to the center of the fixed plate 131); in addition, the coordinates of the same point can be indirectly converted through the camera modules 132 at different angles of the fixed plate 131, so as to obtain two strains with an angle of 45° with the horizontal strain and the vertical strain. Therefore, four sets of strain data in four different directions can be obtained at one measuring point.

[0126] In actual application, the mining stress monitoring device 100 can measure the full-field strain in the preset borehole 401 through three or more image acquisition modules 130, rather than being limited to a single measurement point, so as to obtain more data calculations and reduce calculation errors. In addition, in order to accurately obtain the deformation of the inner wall of the preset borehole 401, so that each camera module 132 can accurately collect strain data in a specified direction, the camera module 132 can be tilted 15° toward the side close to the column 120, which will not be repeated here.

[0127] For example, taking the mining stress monitoring device 100 having three image acquisition modules 130 as an example, when the image acquisition module 130 is used to obtain the strain data of the speckle pattern, the source of the strain data can be divided into three parts. Since the column 120 is a regular triangular prism, so that each image acquisition module 130 is spaced 120° along the circumferential angle, the three image acquisition modules 130 can be sequentially recorded as a 0° image acquisition module, a 120° phase image acquisition module, and a 240° image acquisition module; Figure 7C As shown, the vertical direction is set as the 0° direction of the point monitored by the camera, and each image acquisition module 130 has four camera modules 132, so strain data at four positions can be obtained, that is, strain data in 12 directions can be obtained through the dynamic stress monitoring module.

[0128] In some embodiments, the pressure loading device 300 is controlled to drive the mining stress monitoring device 100 to be calibrated, which includes:

[0129] The control data processing system 200 debugs the application parameters of the mining stress monitoring device 100 , wherein the application parameters include the shooting focal length of the image acquisition module 130 and the light intensity of the light source 140 .

[0130] Specifically, before calibrating the mining stress monitoring device 100, in order to ensure that the mining stress monitoring device 100 can obtain clearer images and improve the accuracy of obtaining strain data, the data processing system 200 debugs the application parameters of the mining stress monitoring device 100, such as adjusting the shooting focal length of the image acquisition module 130 and the light intensity of the light source 140, to ensure that clearer and more accurate image information can be obtained during the test.

[0131] It should be noted that, since the rock sample 400 is subjected to stress, the preset borehole 401 will be deformed, thereby changing the shooting focal length of the image acquisition module 130 and affecting the collection of strain data. Therefore, the data processing system 200 can dynamically adjust the shooting focal length of the image acquisition module 130 through the control module 150 to ensure the effect of its acquisition of strain data.

[0132] It should be noted that the above describes some embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the above embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0133] The various embodiments in the present application are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0134] The description of the present application is given for the purpose of illustration and description, and is not intended to be exhaustive or to limit the present application to the disclosed form. Many modifications and variations are obvious to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present application, and to enable those of ordinary skill in the art to understand the present application and thus design various embodiments with various modifications suitable for specific purposes.

[0135] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application (including the claims) is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0136] Although the present application has been described in conjunction with specific embodiments thereof, many alternatives, modifications and variations of these embodiments will be apparent to those skilled in the art in light of the foregoing description.

[0137] The embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of the present application.

Claims

1. A test method for monitoring the state of mining stress changes based on strain image detection, characterized in that: The test method uses mining stress monitoring equipment, a data processing system and a pressure loading device; the mining stress monitoring equipment is connected to the data processing system, and the pressure loading device is connected to two first pressure plates, two second pressure plates and two third pressure plates in the first direction, the second direction and the third direction respectively; the two first pressure plates, the two second pressure plates and the two third pressure plates together enclose a loading space; wherein any one of the first direction, the second direction and the third direction is perpendicular to the other two directions; The test method includes: Providing a rock sample, wherein the rock sample has a preset borehole; forming a speckle pattern on the inner wall surface of the preset borehole, installing the mining stress monitoring device in the preset borehole, and plugging the port of the preset borehole; Assemble the rock sample in the loading space, and make the port of the preset borehole face any of the third pressure plates, and control the pressure loading device to calibrate the mining stress monitoring equipment; Controlling the pressure loading device to drive the first pressing plate, the second pressing plate and the third pressing plate to load stress on the rock sample at a constant loading rate, until the stresses on the rock sample in the first direction, the second direction and the third direction reach a first preset stress, a second preset stress and a third preset stress, respectively, wherein the first preset stress, the second preset stress and the third preset stress decrease in sequence; adjusting at least one of the first preset stress, the second preset stress and the third preset stress based on the current simulated working condition, acquiring strain data of the speckle pattern in the current simulated working condition through the mining stress monitoring device, and sending the strain data to a data processing system; In response to determining that the data processing system has received the strain data, determining a test stress of the rock sample based on the strain data; The measurement result of the mining stress monitoring equipment is determined based on the comparison result of the test stress and the reference stress of the rock sample at the same time, wherein the reference stress is the stress loaded by the pressure loading device to the rock sample at that time.

2. The test method for monitoring the state of mining stress changes based on strain image detection according to claim 1 is characterized in that: The adjusting at least one of the first preset stress, the second preset stress, and the third preset stress based on the current simulated working condition comprises: Determining the type of the current simulation working condition; In response to determining that the current simulated working condition is a stress change working condition simulating an original rock stress field, controlling the pressure loading device to drive the first pressing plate to load stress to the rock sample at a preset loading rate until the stress on the rock sample in the first direction reaches a first target stress, wherein the first target stress is greater than the first preset stress; In response to determining that the current simulated working condition is a stress change working condition simulating tunnel excavation unloading, controlling the pressure loading device to drive the second pressing plate to remove stress from the rock sample at a preset unloading rate until the stress on the rock sample in the second direction is zero; In response to determining that the current simulated working condition is a stress change working condition simulating a blasting scenario, a disturbance device is provided, and the disturbance device is controlled to adjust the first preset stress according to a preset frequency and a preset amplitude.

3. The test method for monitoring the state of mining stress changes based on strain image detection according to claim 1 is characterized in that: The blocking of the port of the preset drilling hole comprises: The port of the preset borehole is sealed with a filling material made of the same material as the rock sample, and the filling material is dried.

4. The test method for monitoring the state of mining stress changes based on strain image detection according to claim 1 is characterized in that: The controlling the pressure loading device to calibrate the mining stress monitoring equipment includes: The pressure loading device is controlled to drive the first pressure plate, the second pressure plate and the third pressure plate to load stress to the rock sample respectively until the stress on the rock sample in the first direction, the second direction and the third direction reaches a preset verification stress.

5. The test method for monitoring the state of mining stress changes based on strain image detection according to claim 4 is characterized in that: Later also includes: In response to determining that the data processing system receives the verification data acquired by the mining stress monitoring device during the verification process, the data processing system is controlled to perform initialization processing on the verification data.

6. The test method for monitoring the state of mining stress changes based on strain image detection according to claim 1 is characterized in that: The test stress includes a plurality of sub-test stresses, the reference stress includes a plurality of sub-reference stresses, and each of the sub-test stresses corresponds to a sub-reference stress; Determining the measurement result of the mining stress monitoring device according to the comparison result of the test stress and the reference stress of the rock sample at the same time includes: Determine a plurality of sub-stress deviation values ​​according to a plurality of the sub-test stresses and a plurality of corresponding sub-reference stresses; The plurality of sub-stress deviation values ​​are respectively compared with preset deviation thresholds, and based on the comparison results, it is determined whether the measurement result of the mining stress monitoring equipment at the current moment meets the monitoring requirements.

7. The test method for monitoring the state of mining stress changes based on strain image detection according to claim 6 is characterized in that: The step of comparing the plurality of sub-stress deviation values ​​with preset deviation thresholds respectively, and judging whether the measurement result of the mining stress monitoring device at the current moment meets the monitoring requirements based on the comparison result, includes: In response to determining that the plurality of sub-stress deviation values ​​are all less than or equal to the preset deviation threshold, the measurement result of the mining stress monitoring device at the current moment meets the monitoring requirement; In response to determining that at least one of the plurality of sub-stress deviation values ​​is greater than the preset deviation threshold, the measurement result of the mining stress monitoring device at the current moment does not meet the monitoring requirements.

8. The test method for monitoring the state of mining stress changes based on strain image detection according to any one of claims 1 to 7, characterized in that: The mining stress monitoring device includes: two baffles, a column, at least three image acquisition modules, a light source, a control module, a storage module and a power supply; The two baffles are fixedly connected to opposite ends of the column respectively; The column is a regular triangular prism, and is provided with three mounting side surfaces connected in pairs along its circumference, and each of the mounting side surfaces is connected to at least one group of the image acquisition modules; The light source is arranged on a side of the baffle close to the column; A shell is provided on one side of one of the two baffles away from the column, and the control module, the storage module and the power supply are all located in the shell; The control module is respectively connected to at least three of the image acquisition modules and the light source; The power supply is electrically connected to at least three of the image acquisition modules, the light source and the storage module respectively.

9. The test method for monitoring the state of mining stress changes based on strain image detection according to claim 8 is characterized in that: Each of the image acquisition modules comprises: two fixing plates and four camera modules; The two fixing plates are respectively fixedly connected to the same mounting side surface, the extension directions of the two fixing plates are at an angle of 45°, and the extension direction of one of the two fixing plates is perpendicular to the extension direction of the column; Each of the fixing plates is provided with two camera modules, the two camera modules and the column are located on the same side of the fixing plate, and the two camera modules are located on two opposite sides of the column and are symmetrically arranged.

10. The test method for monitoring the state of mining stress changes based on strain image detection according to claim 9 is characterized in that: The controlling the pressure loading device to calibrate the mining stress monitoring equipment comprises: The data processing system is controlled to debug application parameters of the mining stress monitoring device, wherein the application parameters include the shooting focal length of each camera module and the illumination intensity of each light source.

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