A test device and method for induced boundary pillar destruction by backfilling an open pit with tailings

Abstract

The present invention relates to the technical field of boundary pillar destruction induced by backfilling open pits, and in particular to a test device and method for boundary pillar destruction induced by backfilling open pits with tailings, comprising: a test assembly; a conveying assembly connected to the test assembly and used to uniformly input tailings into the test assembly; a pressure control assembly connected to the test assembly and used to control the pressure in the test assembly; and a monitoring component provided on the test assembly and used to monitor data information in the test assembly while changing the internal pressure of the test assembly. The conveying assembly provides uniformly distributed tailings to the test assembly, the pressure control assembly simulates actual pressure conditions, and the monitoring component acquires data in real time, together forming a complete and effective experimental device, which realizes a simulation experiment on the situation related to boundary pillar destruction induced by backfilling open pits with tailings in a controllable and safe laboratory environment, solving the problem of high experimental cost and high risk in traditional research.

Description

Technical Field

[0001] The present invention relates to the technical field of boundary pillar destruction induced by backfilling an open pit, and in particular to a test device and method for boundary pillar destruction induced by backfilling an open pit with tailings. Background Art

[0002] With the gradual depletion of shallow mineral resources, deeper mining is becoming an inevitable trend. At the same time, the concepts of environmental protection and sustainable resource utilization are becoming increasingly popular, and the technology of converting open-pit tailings backfill to underground mining is gradually gaining popularity. On the one hand, this technology can effectively reduce the environmental impact of tailings accumulation, mitigate safety risks such as tailings dam failure, avoid the occupation of large amounts of land resources, and reduce damage to the surrounding ecological environment. On the other hand, appropriate tailings backfill can improve the stability of open-pit slopes and reduce the costs of slope monitoring and treatment. However, to date, the conversion of open-pit tailings backfill to underground mining technology is mostly in the experimental stage, and the selection of key technical parameters still requires extensive testing. A key parameter is the thickness of the boundary pillar. As a key structure that separates different mining areas or protects important facilities, the stability of the boundary pillar is directly related to the overall safety of the mine. When tailings are backfilled into the open pit, the interaction between the backfill and the surrounding rock mass and the stress changes during the mining process will have a complex impact on the stability of the boundary pillar. If these impact mechanisms are not accurately understood, boundary pillars may become unstable and damaged, leading to a series of safety accidents above and below ground, posing a huge threat to mine safety production.

[0003] Existing research of this type often faces high experimental costs, mainly because traditional experimental methods require large-scale experiments that truly simulate the actual mining environment. From site preparation, material collection to equipment investment, a large amount of resources are consumed. At the same time, conducting experiments in actual scenarios is dangerous. For example, in the process of simulating tailings backfill and mining stress changes, emergencies such as boundary pillar instability similar to those in actual mines may occur, posing a serious threat to the life safety of experimental personnel and experimental equipment. There is an urgent need to provide an experimental device and method for boundary pillar destruction induced by tailings backfill in open pits. Summary of the Invention

[0004] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a test device and method for the destruction of boundary pillars induced by tailings backfilling open pits, which solves the technical problems that the existing research experiments on the destruction of boundary pillars induced by tailings backfilling open pits are costly and have certain risks.

[0005] In order to achieve the above objectives, the main technical solutions adopted by the present invention include:

[0006] In a first aspect, an embodiment of the present invention provides a test device for inducing boundary pillar destruction by backfilling an open pit with tailings.

[0007] An embodiment of the present invention provides a test device for detecting boundary pillar damage induced by backfilling an open pit with tailings, comprising:

[0008] Test components;

[0009] A conveying assembly connected to the testing assembly and used for uniformly feeding tailings into the testing assembly;

[0010] A pressure control component, connected to the test component, for controlling the pressure in the test component;

[0011] The monitoring component is arranged on the test assembly and is used to monitor the data information in the test assembly when the internal pressure of the test assembly is changed.

[0012] Optionally, the test components include:

[0013] test box;

[0014] The test plate is arranged inside the test box so as to form a funnel-shaped open pit model inside the test box;

[0015] The boundary pillar model is placed in the test box and located at the bottom of the open pit model;

[0016] The mining body component model is arranged in the test box and contacts the bottom of the boundary pillar model to support the boundary pillar model.

[0017] Optionally, the mining volume component model includes:

[0018] A plurality of first mining bodies are arranged in parallel in the test box and are in contact with the bottom of the boundary pillar model;

[0019] The second mining body is arranged between adjacent first mining bodies and contacts the bottom of the boundary pillar model.

[0020] Optionally, the delivery assembly includes:

[0021] The protective shell is arranged on the test box and has a plurality of drop openings at the bottom thereof connected to the open pit model;

[0022] The drive shaft is coaxially mounted in the protective housing;

[0023] The blocking plates are staggered and fixedly arranged on the driving shaft. When the blocking plates are in contact with the blanking opening, the blocking plates block the blanking opening.

[0024] A material storage component is connected to the protective shell and is used to transport tailings into the protective shell;

[0025] The vibration component is arranged on the outer wall of the test box and is used to spread the tailings in the open pit model evenly.

[0026] Optionally, the storage component includes:

[0027] Storage box for storing tailings;

[0028] A conveying pipe connected between the storage box and the protective shell;

[0029] The auger is installed in the conveying pipe and is used to convey tailings.

[0030] Optionally, the monitoring component includes:

[0031] Fiber Bragg grating sensors are installed inside the boundary pillar model;

[0032] A pressure sensor is provided at the bottom of the mining body component model;

[0033] Several acoustic emission probes are equidistantly arranged on one side of the test box;

[0034] The thermal infrared camera is set at an equal distance on the other side of the test box.

[0035] Optionally, the pressure control assembly includes:

[0036] Hydraulic cylinder;

[0037] The pressure plate is arranged on the top of the test box and is connected to the output end of the hydraulic cylinder to change the pressure in the open pit model.

[0038] In a second aspect, an embodiment of the present invention provides a test method for detecting boundary pillar damage induced by backfilling an open pit with tailings.

[0039] An embodiment of the present invention provides a test method for inducing boundary pillar destruction by backfilling an open pit with tailings, using the test device for inducing boundary pillar destruction by backfilling an open pit with tailings as described in the first aspect:

[0040] Producing a mining body component model, a boundary pillar model, and an open pit model in sequence, wherein the mining body component model includes a first mining body and a second mining body that are adjacently arranged;

[0041] Evenly spread the tailings in the open pit model and compact it with a compaction degree of ≥90% to form a filling model;

[0042] Applying vertical load to the filling model to obtain a compacted backfill model;

[0043] After the first mining body is removed and filled with a backfill body, the second mining body is removed. If the boundary pillar model is not destroyed after mining, a static load is applied to the backfill model at a rate of 0.1 MPa / min until the boundary pillar model is destroyed. At the same time, historical data of the boundary pillar model is obtained and preprocessed to obtain processed data.

[0044] Inputting the processed data into the hybrid deep learning model to obtain a trained hybrid deep learning model;

[0045] Input real-time data into the trained hybrid deep learning model to obtain the pillar safety factor;

[0046] When the safety factor of the pillar is 0.8≤<1.0, reduce the loading rate to 0.05MPa / min;

[0047] When the safety factor of the pillar is 0.5≤<0.8, the static load on the backfill model is suspended;

[0048] When the pillar safety factor is less than 0.5, stop applying static load to the backfill model and give an alarm, and save the experimental data.

[0049] Optionally, the steps of making the open pit model and the boundary pillar model further include:

[0050] Mix barite powder, river sand, gypsum and water in a ratio of 1:4:1.25:1.25, cast into an open pit model of 1:100 or 1:200, and cure for 7 days to form;

[0051] The boundary pillar model was prepared by mixing barite powder, river sand, gypsum and water in a ratio of 1:3.75:1.5:1.25. After curing for 7 days, it was buried in the open pit model at the designated position.

[0052] Optionally, the step of making the filling model further includes:

[0053] Tailings, cement and water are mixed according to the mass ratio, wherein the cement content is 5%, 10% and 15%, the water-solid ratio is 0.2, and the tailings particle size is less than 2mm.

[0054] The beneficial effects of the present invention are as follows: the test device and method for boundary pillar destruction induced by tailings backfilling an open pit of the present invention include a test component, a conveying component and a pressure control component. The conveying component provides evenly distributed tailings to the test component, the pressure control component simulates actual pressure conditions, and the monitoring component obtains data in real time, which together constitute a complete and effective experimental device, realizing a simulation experiment on the situation related to boundary pillar destruction induced by tailings backfilling an open pit in a controllable and safe laboratory environment, solving the problem of high experimental cost and high risk in traditional research. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 This is a schematic diagram of the three-dimensional structure of a test device for inducing boundary pillar destruction by backfilling an open pit with tailings according to the present invention;

[0056] Figure 2 is a schematic cross-sectional structural diagram of the test assembly of the present invention;

[0057] Figure 3 Schematic diagram of the top view of the test assembly of the present invention;

[0058] Figure 4 It is a schematic cross-sectional structural diagram of the conveying assembly of the present invention;

[0059] Figure 5 Schematic diagram of the cross-sectional structure of the material storage assembly of the present invention;

[0060] Figure 6 The present invention is a flow chart of the test method for inducing boundary pillar destruction by backfilling an open pit with tailings.

[0061] Description of Reference Numerals

[0062] 100-test component, 200-transmission component, 300-pressure control component, 400-monitoring component;

[0063] 110-test box, 120-test plate, 130-boundary pillar model, 140-mining body component model;

[0064] 210-protective shell, 220-drive shaft, 230-blocking plate, 240-storage assembly, 250-vibrating component;

[0065] 310-hydraulic cylinder, 320-pressure plate;

[0066] 410-fiber Bragg grating sensor, 420-pressure sensor, 430-acoustic emission probe, 440-thermal infrared camera;

[0067] 141-first mining body, 142-second mining body;

[0068] 241-storage box, 242-conveying pipe, 243-auger;

[0069] 101- open pit model, 201- blanking port. DETAILED DESCRIPTION

[0070] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below with reference to the accompanying drawings and through specific embodiments. Figure 1 The orientation is referenced.

[0071] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. Instead, these embodiments are provided to enable a clearer and more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0072] like Figures 1 to 5 As shown, according to the first aspect of the embodiment of the present application, a test device for boundary pillar destruction induced by tailings backfilling in an open pit is proposed, including: a test component 100; a conveying component 200, connected to the test component 100, for uniformly inputting tailings into the test component 100; a pressure control component 300, connected to the test component 100, for controlling the pressure inside the test component 100; a monitoring component 400, arranged on the test component 100, for monitoring data information in the test component 100 when changing the internal pressure of the test component 100.

[0073] The test apparatus for boundary pillar failure induced by tailings backfilling an open pit provided in the present application includes a test assembly 100, a conveying assembly 200, and a pressure control assembly 300. The test assembly 100 provides a basic space for simulating the stress conditions of the tailings backfilling open pit and the boundary pillars in this environment and is the core component for the interaction of various experimental factors and data generation.

[0074] The conveying component 200 is connected to the test component 100. Its main function is to evenly input tailings into the test component 100. This component ensures that the tailings can enter the test component 100 in a stable and uniform manner, simulating the distribution state of the tailings during the actual backfill process, and providing a basis for the subsequent accurate simulation of the interaction between the tailings and the rock mass (boundary pillars). By controlling the flow rate, flow rate and other parameters of the conveying component 200, the accumulation of tailings under different backfill conditions can be accurately simulated.

[0075] The pressure control component 300 is connected to the test component 100 and is responsible for controlling the pressure inside the test component 100. During actual mining, pressure changes are one of the key factors affecting the stability of boundary pillars. The pressure control component can simulate the pressure changes in different mining stages and under different working conditions through precise control means, so that the pressure environment inside the test component 100 is as close to reality as possible. The simulation can conduct in-depth research on the impact of different pressure conditions on the stability of boundary pillars, which is of great significance for determining reasonable mining plans and boundary pillar parameters.

[0076] The monitoring component 400 is set on the test component 100. When the internal pressure of the test component 100 is changed, the data information in the test component 100 is monitored in real time, which can fully reflect the data response of the boundary pillar during the tailings backfill and pressure change process. The monitoring component 400 can obtain the stability changes of the boundary pillar under different experimental conditions by collecting and analyzing these data. In the experimental method, real-time data of the boundary pillar model 130 is collected in real time. These data are input into the hybrid deep learning model after preprocessing to obtain the safety factor of the pillar, and different experimental operations are taken according to the factor. The precise monitoring of the monitoring component 400 provides data support for the entire experiment, enabling researchers to fully understand the mechanical behavior of the boundary pillar during the experiment, and deeply analyze the internal laws of the boundary pillar destruction induced by tailings backfilling in the open pit, providing indispensable data guarantee for evaluating the stability of the boundary pillar.

[0077] To sum up, the various components work closely together, the conveying component 200 provides evenly distributed tailings for the testing component 100, the pressure control component 300 simulates the actual pressure conditions, and the monitoring component 400 obtains data in real time, together forming a complete and effective experimental device. This realizes the simulation experiment of the situation related to the destruction of boundary pillars induced by tailings backfilling open pits in a controllable and safe laboratory environment, solving the problem of high experimental cost and high risk in traditional research.

[0078] like Figures 1 to 5 As shown, in some examples, the test assembly 100 includes: a test box 110; a test plate 120, which is arranged inside the test box 110 so that a funnel-shaped open pit model 101 is formed inside the test box 110; a boundary pillar model 130, which is arranged in the test box 110 and is located at the bottom of the open pit model 101; and a mining body assembly model 140, which is arranged in the test box 110 and contacts the bottom of the boundary pillar model 130 for supporting the boundary pillar model 130.

[0079] In this technical solution, the test box 110 is the external frame structure of the test assembly 100, which serves to accommodate and support the various internal components, providing a stable physical environment for the entire experiment, ensuring that the various components can operate in a relatively closed and stable space during the experiment, avoiding interference from external factors;

[0080] The test plate 120 is arranged inside the test box 110, so that a funnel-shaped open pit model 101 is formed inside the test box 110. This funnel-shaped open pit model 101 is a part that simulates the actual open pit mine shape. In actual open pit mining activities, the shape and structure of the open pit have an important influence on the backfill of tailings and subsequent stress distribution. By constructing such a funnel-shaped open pit model 101 in the test box 110, the experiment can more realistically simulate the natural accumulation of tailings in the open pit and the pressure distribution characteristics. Open pits of different shapes and sizes will cause the accumulation shape and stress transfer path of tailings to be different, and the funnel-shaped open pit model 101 is more in line with the common shape of actual open pit mines, and can provide conditions for subsequent experiments that are closer to actual working conditions, which helps to improve the authenticity and reliability of the experimental results.

[0081] The boundary pillar model 130 is set in the test box 110 and is located at the bottom of the open pit model 101. In actual mining, the boundary pillar model 130 is a key structure, and its stability is directly related to the overall safety of the mine. In this experiment, the boundary pillar model 130 is in a core position. Factors such as the filling of tailings and pressure changes in the open pit model 101 will affect the boundary pillar model 130, thereby causing its mechanical state to change. Through direct monitoring and research on the boundary pillar model 130, we can gain an in-depth understanding of the various forces that the boundary pillar is subjected to and the changes in its stability during the process of tailings backfilling the open pit, providing an important basis for the evaluation and protection of the stability of the boundary pillar in actual mining.

[0082] The mining body component model 140 is set in the test box 110 and is in contact with the bottom of the boundary pillar model 130. It is mainly used to support the boundary pillar model 130. In the actual mining environment, there is a mechanical interaction between the mining body and the boundary pillar. The mining body component model 140 simulates the mining body structure and mechanical environment in the actual mine. During the experiment, the mining body component model 140 needs to be operated according to the experimental steps to simulate the mining process of the actual mine.

[0083] For example, the test box 110 and the two sides of the open pit model 101 are filled with spaces to simulate the rock conditions on site.

[0084] To sum up, the various components in the test assembly 100 work closely together, the test box 110 provides space guarantee, the test plate 120 constructs the open pit model 101, the boundary pillar model 130 serves as the core research object, and the mining body assembly model 140 simulates the mining environment. This design enables the test assembly 100 to accurately and effectively simulate the complex process of tailings backfilling the open pit in an actual mine and the impact of mining activities on the stability of the boundary pillar, providing a solid foundation for the entire test device to realize its function.

[0085] like Figures 1 to 5 As shown, in some examples, the mining body assembly model 140 includes: a plurality of first mining bodies 141 arranged in parallel in the test box 110 and in contact with the bottom of the boundary pillar model 130; and a second mining body 142 arranged between adjacent first mining bodies 141 and in contact with the bottom of the boundary pillar model 130.

[0086] In this technical solution, several first mining bodies 141 are arranged in parallel within the test chamber 110 and in contact with the boundary pillar model 130. This arrangement simulates multiple mining units at different locations in actual mining operations. During actual mining, these dispersed and parallel mining bodies gradually excavate the underground ore body, and each mining body may have varying degrees of impact on the surrounding rock mass, including the boundary pillar. In the experimental environment, the multiple parallel first mining bodies 141 can more realistically reproduce the stress conditions of this multi-source mining, providing simulation conditions for studying the impact of different levels of mining activity on boundary pillars.

[0087] The second mining body 142 is placed between adjacent first mining bodies 141 and also contacts the bottom of the boundary pillar model 130. This placement of the second mining body 142 between adjacent first mining bodies 141 is crucial. In actual mines, ore bodies in different areas may be mined in a specific order based on geological conditions, mining plans, and other factors. The placement of the second mining body 142 allows this complex mining condition to be simulated in the experiment. Its contact with the boundary pillar model 130 also transmits the forces generated by mining to the boundary pillar. Furthermore, due to its unique location between the first mining bodies 141, it alters the transmission path and distribution of surrounding stresses, thereby affecting the mechanical state of the boundary pillar.

[0088] like Figures 1 to 5 As shown, in some examples, the conveying component 200 includes: a protective shell 210, which is arranged on the test box 110 and has several drop-out ports 201 connected to the open pit model 101 formed at the bottom; a drive shaft 220, which is coaxially rotatably installed in the protective shell 210; a sealing plate 230, which is staggered and fixed on the drive shaft 220, and when the sealing plate 230 is in contact with the drop-out port 201, the sealing plate 230 blocks the drop-out port 201; a storage component 240, which is connected to the protective shell 210 and is used to convey tailings into the protective shell 210; a vibration component 250, which is arranged on the outer wall of the test box 110 and is used to evenly spread the tailings in the open pit model 101.

[0089] In this technical solution, a protective shell 210 is installed on the test box 110, providing a protective and supporting structure for the internal components of the entire conveying assembly 200. Several drop-out ports 201 arranged at the bottom and connected to the open pit model 101 are channels for tailings to enter the open pit model 101 from the conveying assembly 200. The drop-out ports 201 are arranged at equal intervals, providing the basic conditions for achieving uniform paving.

[0090] The drive shaft 220 is coaxially mounted in the protective housing 210 and is the core component for power transmission during the entire conveying process. Driven by an external power source, the drive shaft 220 can rotate in a circular motion. This rotation provides power to subsequent components connected to the drive shaft 220, enabling them to collaboratively complete the tailings conveying operation.

[0091] The blocking plates 230 are staggeredly fixed on the driving shaft 220 and cooperate with the discharge port 201. When the blocking plates 230 come into contact with the discharge port 201, they can completely block the discharge port 201 and prevent the tailings from falling. As the driving shaft 220 rotates, the blocking plates 230 leave the discharge port 201, and the tailings can fall into the open pit model 101 through the discharge port 201. The staggered arrangement enables the tailings to enter the open pit model 101 from the protective shell 210 in an intermittent and controllable manner, which helps to accurately control the flow rate and falling position of the tailings, thereby improving the uniformity of the distribution of the tailings in the open pit model 101.

[0092] The storage assembly 240 is connected to the protective shell 210 and is responsible for transporting tailings into the protective shell 210, continuously and stably delivering the tailings into the protective shell 210. The presence of the storage assembly 240 ensures an adequate supply of tailings during the transportation process, providing material support for the continuous simulation of the actual tailings backfill process.

[0093] Vibrating components 250 are disposed on the outer wall of the test box 110. For example, at least two vibrating components 250 may be used, and at least two vibrating components 250 are equidistantly disposed on the outer wall of the test box 110. Their primary function is to evenly distribute the tailings within the open pit model 101. After the tailings enter the open pit model 101 through the discharge port 201, gravity alone cannot guarantee a completely even distribution of the tailings. The vibrating components 250 indirectly act on the tailings within the open pit model 101 by transmitting vibration energy to the test box 110. Under the action of vibration, the tailings particles are subject to additional external force disturbances, allowing them to adjust their position and gradually achieve a more even distribution. This ensures that the compaction of the tailings is relatively consistent throughout the open pit model 101, thereby improving the authenticity and accuracy of the experimental simulation.

[0094] The conveying assembly 200 achieves uniform tailings input to the open pit model 101 in the test assembly 100 through the coordinated cooperation of various components, namely, the storage assembly 240 provides tailings, the drive shaft 220 and the sealing plate 230 control the rhythm and position of the tailings falling, and the vibration component 250 assists in the uniform distribution of the tailings, thereby providing a good material laying foundation for studying the impact of tailings backfill on boundary pillars in subsequent experiments.

[0095] like Figures 1 to 5 As shown, in some examples, the storage assembly 240 includes: a storage box 241 for storing tailings; a delivery pipe 242 connected between the storage box 241 and the protective shell 210; and an auger 243 disposed in the delivery pipe 242 for delivering tailings.

[0096] In this technical solution, the storage box 241 is a container for storing tailings, and its main function is to serve as a "warehouse" to accommodate a certain amount of tailings to meet the needs of continuous transportation during the experiment; the delivery pipe 242 is a "bridge" connecting the storage box 241 and the protective shell 210, which serves to communicate the two important components and realize the directional transportation of tailings. It provides a closed path for transporting tailings from the storage area to the unloading area by connecting the storage box 241 and the protective shell 210, preventing the tailings from being scattered or disturbed by external factors during the transportation process. For example, the inner wall material can be selected from a smooth and wear-resistant material to reduce the friction between the tailings and the inner wall of the pipe, reduce wear, and extend the service life of the delivery pipe 242; a reliable connection method ensures that there will be no falling off or leakage during the transportation of tailings, thereby ensuring the sealing and stability of the entire transportation system.

[0097] The auger 243 is arranged inside the conveying pipe 242, also known as a screw conveyor. Its working principle is to rotate the spiral blades around the central axis, pushing the tailings forward along the direction of the spiral blades during rotation, thereby transporting the tailings from the storage box 241 to the protective shell 210. This conveying method can transport the tailings from one end to the other more smoothly and efficiently, and the conveying speed and flow of the tailings can be controlled by adjusting the rotation speed of the auger 243.

[0098] like Figures 1 to 5 As shown, in some examples, the monitoring component 400 includes: a fiber optic Bragg grating sensor 410, which is arranged inside the boundary pillar model 130; a pressure sensor 420, which is arranged at the bottom of the mining body component model 140; a plurality of acoustic emission probes 430, which are equidistantly arranged on one side of the test box 110; and a thermal infrared camera 440, which is equidistantly arranged on the other side of the test box 110.

[0099] In this technical solution, a fiber grating sensor 410 is installed inside the boundary pillar model 130. During the tailings backfill process and under the influence of mining activities, the internal mechanical state of the boundary pillar model 130 will undergo complex changes, such as changes in the distribution of stress and strain. The fiber grating sensor 410 can accurately sense the changes in these internal physical quantities. Due to the sensitivity of the fiber grating to environmental parameters, when stress or strain changes occur inside the boundary pillar model 130, the reflection wavelength of the fiber grating will change accordingly. By detecting this wavelength change, real-time information on the internal stress and strain of the boundary pillar model 130 can be obtained. This is of key significance for in-depth understanding of the internal stress conditions of the boundary pillar under different working conditions and judging whether it is close to a state of destruction. It helps researchers accurately grasp the changing process of the stability of the boundary pillar.

[0100] The pressure sensor 420 is placed at the bottom of the mining body component model 140. The mining body component model 140 will generate pressure on the bottom during the mining simulation. The function of the pressure sensor 420 is to accurately measure the size and changes of this pressure. By obtaining the pressure data of the mining body component model 140 acting on the bottom, the force of the mining activity on the lower strata can be understood. This is of great value for studying how the mining activity affects the boundary pillars through the bottom transmission. At the same time, combined with other monitoring data, it can more comprehensively analyze the mechanical transmission path and influence range of the mining activity in the entire experimental system, and provide important pressure parameter basis for in-depth research on the relationship between tailings backfill and boundary pillar destruction.

[0101] Several acoustic emission probes 430 are equidistantly positioned on one side of the test chamber 110. Acoustic emission (AE) is the elastic wave phenomenon generated when a material deforms or fractures under stress. During the experiment, AE signals were generated when the boundary pillar model 130 underwent slight deformation, crack propagation, and eventual failure. The equidistantly positioned AE probes 430 are capable of receiving these AE signals over a wide range and converting them into electrical signals for transmission and analysis. By monitoring and analyzing these AE signals, researchers can obtain information on internal material deformation and damage development, such as determining the crack initiation location, propagation direction, and rate of growth.

[0102] Thermal infrared camera 440 was positioned equidistantly on the other side of test chamber 110. During the experiment, the surface temperature of various objects within test chamber 110 varied due to factors such as tailings backfill, mining activities, and component deformation. Thermal infrared camera 440 received infrared radiation from the objects and converted it into thermal images, visually displaying the distribution of surface temperature and its changes over time. Monitoring with thermal infrared camera 440 revealed areas of abnormal temperature during the experiment, which may be related to internal stress concentration, energy dissipation, and damage development. Analysis of temperature changes further illuminated the distribution and conversion of energy during the experiment, providing valuable supplementary information for a comprehensive study of the physical processes involved in boundary pillar failure induced by tailings backfill in open pits.

[0103] like Figures 1 to 5 As shown, in some examples, the pressure control assembly 300 includes: a hydraulic cylinder 310 ; a pressure plate 320 disposed on the top of the test box 110 and connected to the output end of the hydraulic cylinder 310 for changing the pressure in the open pit model 101 .

[0104] In this technical solution, the hydraulic cylinder 310 is the power source of the pressure control component 300, which generates a powerful driving force through the pressure change of the hydraulic oil. In the experimental device, the piston rod of the hydraulic cylinder 310 is controlled to extend and retract, providing adjustable power output for the entire pressure control component 300, and is the core driving component for realizing pressure changes.

[0105] The pressure plate 320 is set on the top of the test box 110 and is closely connected to the output end of the hydraulic cylinder 310. It acts as a "pressure transmission messenger", evenly applying the force generated by the hydraulic cylinder 310 to the tailings in the open pit model 101. The pressure plate 320 is located in the middle part of the open pit model 101. For example, the length of the pressure plate 320 can be selected to be half the length of the top of the open pit model 101 to ensure that when it contacts the top of the open pit model 101, the received pressure can be distributed more evenly on the surface of the open pit model 101, wherein the maximum pressure load is 1 MPa.

[0106] For example, the pressure plate 320 can be of various sizes and can be selectively installed at the output end of the hydraulic cylinder 310 .

[0107] When the experiment requires changing the pressure within the open pit model 101, the external hydraulic control system adjusts the hydraulic oil in the hydraulic cylinder 310 according to the set parameters. For example, increasing the hydraulic oil pressure causes the piston rod of the hydraulic cylinder 310 to extend. The extension of the piston rod drives the connected pressure plate 320 downward, causing the pressure plate 320 to gradually approach and generate pressure on the top of the open pit model 101. This pressure is transmitted to various parts of the open pit model 101 through the tailings, thereby increasing the pressure within the open pit model 101. Conversely, if the pressure needs to be reduced, the hydraulic control system reduces the hydraulic oil pressure in the hydraulic cylinder 310, retracts the piston rod, and moves the pressure plate 320 upward, reducing the pressure on the open pit model 101. In this way, the pressure control assembly 300 can accurately and continuously change the pressure within the open pit model 101 to meet the pressure simulation requirements under different experimental conditions, making the experimental results more realistic and facilitating in-depth research on the relationship between tailings backfill, open pit pressure, and boundary pillar stability.

[0108] like Figure 6 As shown, according to the second aspect of the embodiment of the present application, a test method for inducing boundary pillar destruction by backfilling an open pit with tailings is proposed, using the test device for inducing boundary pillar destruction by backfilling an open pit with tailings proposed in the first aspect above:

[0109] S100: Producing a mining body assembly model 140, a boundary pillar model 130, and an open pit model 101 in sequence. The mining body assembly model 140 includes a first mining body 141 and a second mining body 142 that are adjacently arranged.

[0110] In step S100, the steps of making the open pit model 101 and the boundary pillar model 130 also include: mixing barite powder, river sand, gypsum and water in a ratio of 1:4:1.25:1.25, casting a 1:100 or 1:200 open pit model 101, and curing for 7 days to form it; mixing barite powder, river sand, gypsum and water in a ratio of 1:3.75:1.5:1.25 to prepare a boundary pillar model 130, and burying it in the open pit model 101 at a specified position after curing for 7 days.

[0111] S200: evenly spread tailings in the open pit model 101 and compact it, with a compaction degree of ≥90%, to form a filling model;

[0112] In step S200, the step of making the filling mold further includes: using a vibrating screening machine to pass the tailings through a 10-mesh square hole sieve to ensure that the tailings have a particle size of less than 2 mm, and preparing the binder by mixing the tailings, cement, and water according to a mass ratio, wherein the cement content is 5%, 10%, and 15%, and the water-to-solid ratio is 0.2;

[0113] For example, ordinary Portland cement PO42.5 can be used as cement.

[0114] Filling parameter setting: Filling height is converted according to the scale model (1:100) or (1:200), and the equivalent height is set to 100m, and the model is 0.2m, 0.4m, and 1.0m;

[0115] Cementation conditions: dry tailings, 0% cement, and cemented tailings, 5%, 10%, 15% cement content;

[0116] Dry tailings filling: Start the conveying component 200 with a flow rate of 30 kg / min, and evenly spread the tailings on the bottom of the open pit model 101, with a thickness of 10 cm per layer and an error of ±1 cm;

[0117] After each layer is filled, start the pressure plate 320, with a frequency of 50 Hz, an amplitude of 2 mm, and a pressure of 0.5 MPa. Repeat the compaction three times to ensure that the compaction degree is ≥ 90%;

[0118] Compaction degree calculation formula: ; Where C is the degree of compaction (%), ρ d is the measured dry density (g / cm³), ρ max is the maximum dry density (g / cm³).

[0119] S300: applying a vertical load to the filling model to obtain a compacted backfill model;

[0120] Static load application: vertical load, the hydraulic cylinder 310 applies static load at a rate of 0.1 MPa / min until the pressure corresponding to the equivalent filling height is reached.

[0121] S400: After the first mining body 141 is removed and filled with a filling body, the second mining body 142 is removed. If the boundary pillar model 130 is not destroyed after mining, a static load is applied to the backfill model at a rate of 0.1 MPa / min until the boundary pillar model 130 is destroyed. At the same time, historical data of the boundary pillar model 130 is obtained and pre-processed to obtain processed data.

[0122] Step S400 is a mining disturbance simulation. During the test, the strain response and acoustic emission signal of the boundary pillar model 130 are kept and recorded. First, the first-step mine chamber mining is simulated, and the first mining body 141 is excavated one by one. After it is completely excavated, all the gaps are filled one by one with simulated filling bodies. Then, the second-step mine chamber mining is simulated, and the simulated second mining body 142 is excavated one by one. After completion, if the boundary pillar model 130 is not damaged, a static load is applied at a rate of 0.1 MPa / min until the boundary pillar is damaged.

[0123] The strain distribution inside the boundary pillar model 130 is monitored in real time by a fiber Bragg grating sensor 410 at a sampling frequency of 1 kHz;

[0124] The event count rate and energy accumulation value of the acoustic emission signal are captured by the acoustic emission probe 430, and the high-frequency noise is eliminated by using a wavelet threshold denoising method;

[0125] The surface temperature distribution of the boundary pillar model 130 is collected at a frequency of 5 Hz by a thermal infrared camera 440 to generate a thermal map, and the temperature data is smoothed using a sliding average filter;

[0126] Sensor calibration, fiber Bragg grating sensor 410: Use a strain calibration frame to apply a known displacement with an accuracy of 1 μm to calibrate the strain sensitivity coefficient.

[0127] Sensor calibration, fiber Bragg grating sensor 410: use a strain calibration frame to apply a known displacement with an accuracy of 1μm to calibrate the strain sensitivity coefficient ; where K ε is the strain sensitivity coefficient (pm / με), Δλ is the wavelength change (pm), λ0 is the initial center wavelength (nm), and Δε is the strain change (με);

[0128] Acoustic emission probe 430: Use the pencil lead breakage method, Hsu-Nielsen source, calibrate sensitivity, and ensure a frequency response range of 20kHz-1MHz;

[0129] Sensor pre-embedding: Drill a 5mm diameter hole inside the boundary pillar model 130, implant the fiber Bragg grating sensor 410, and seal it with epoxy resin to ensure that the strain transmission efficiency is ≥95%;

[0130] Temperature field monitoring: A thermal infrared camera 440 collects the surface temperature distribution of the boundary pillar model 130 at a frequency of 5 Hz and generates a thermal map with a resolution of 640×480;

[0131] Wavelet threshold denoising: Perform 5-layer wavelet decomposition on the acoustic emission signal, basis function: db4, and soft threshold processing to eliminate high-frequency noise;

[0132] Sliding average filtering: A sliding average with a window length of 10 is used for temperature data. The formula is: ; Among them, T filtered is the filtered temperature value (℃), T i is the original temperature data point, N is the size of the sliding window;

[0133] Feature extraction: Strain features: Calculate mean ;variance ;

[0134] is the average value of strain, is the variance of the strain, n is the total amount of strain data, is the i-th strain data.

[0135] Frequency domain analysis of acoustic emission: Extract the main frequency energy ratio through FFT, formula ; Among them E main is the main frequency band energy, E total is the total energy.

[0136] S500: Inputting the processed data into the hybrid deep learning model to obtain a trained hybrid deep learning model;

[0137] Input strain, acoustic emission, and temperature data into a hybrid deep learning model, using an LSTM-CNN fusion architecture, to calculate pillar safety factors (SF) in real time and dynamically adjust loading conditions based on an early warning mechanism.

[0138] Model architecture design: LSTM branch, input is strain and acoustic emission series with a time window length of 60 seconds, sampling interval of 0.1 seconds, a total of 600 data points, 3 layers of LSTM units, 128 hidden layer nodes, and output time-dependent feature vectors. CNN branch, input is 224×224 pixel crack image and temperature thermogram, using pre-trained ResNet-50 to extract spatial features. Fusion layer: splicing LSTM and CNN outputs, through a fully connected layer, node 256→128→1, mapped to the safety factor (SF);

[0139] Model training: loss function, Huber loss, formula is ;

[0140] Optimizer: Adam optimizer, learning rate 1e-4, batch size 32, training epochs 100;

[0141] Where y is the true safety factor, y^ is the predicted safety factor, and δ is the threshold parameter, which is set to 1.0.

[0142] S600: Input real-time data into the trained hybrid deep learning model to obtain the pillar safety factor; the real-time data includes strain, acoustic emission and temperature data. When the pillar safety factor is 0.8≤<1.0, the loading rate is reduced to 0.05MPa / min; when the pillar safety factor is 0.5≤<0.8, the static load on the backfill model is suspended; when the pillar safety factor is <0.5, the static load on the backfill model is stopped and an alarm is issued, and the experimental data is saved.

[0143] Safety factor (SF) calculation logic: ;The critical load is fitted by historical test data;

[0144] Three-level warning mechanism: Level 1 warning, 0.8≤SF<1.0, reduce the loading rate to 0.05MPa / min, and manually check for data anomalies;

[0145] Level 2 warning, 0.5≤SF<0.8, loading is suspended;

[0146] If the third-level warning SF is less than 0.5, the pressure control component 300 will be immediately cut off, an audible and visual alarm will be sounded, and the experimental data will be saved.

[0147] The specific steps for failure mode analysis and critical parameter calculation are as follows;

[0148] Failure mode determination: Tensile failure: The crack extends symmetrically along the center line of the boundary pillar model 130, and the acoustic emission events are concentrated in the middle and upper parts, with coordinate x>0.5L, where L is the pillar height;

[0149] Shear failure: The cracks are cross-cutting at an angle of 45° to 60°, and the cumulative acoustic emission energy accounts for ≥60% in the bottom area;

[0150] Calculation of critical parameters: Safe filling height: Fit the test data through Logistic regression, the formula is: ;

[0151] Bond strength threshold: The failure probability is analyzed using Weibull distribution to determine the minimum cement content within a 95% confidence interval;

[0152] Among them, H safe is the safe filling height (m), H max is the maximum filling height of the test (m), k is the material attenuation coefficient, f c is the compressive strength of the cemented body (MPa), and f0 is the reference strength (MPa).

[0153] In the description of the present invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0154] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0155] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0156] In the description of this specification, the terms "one embodiment", "some embodiments", "embodiments", "examples", "specific examples" or "some examples" refer to the specific features, structures, materials or characteristics described in conjunction with the embodiment or example and included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and features of different embodiments or examples, unless they are mutually inconsistent.

[0157] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may alter, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A test device for induced boundary pillar destruction in open pits backfilled with tailings, characterized in that: include: TestComponent(100); A conveying assembly (200) connected to the testing assembly (100) and used to uniformly input tailings into the testing assembly (100); a pressure control component (300), connected to the test component (100), and used to control the pressure in the test component (100); A monitoring component (400) is provided on the test assembly (100) and is used to monitor data information in the test assembly (100) when the internal pressure of the test assembly (100) is changed; The test assembly (100) comprises: Test box (110); A test plate (120) is disposed inside the test box (110) so as to form a funnel-shaped open pit model (101) inside the test box (110); A boundary pillar model (130) is disposed in the test box (110) and is located at the bottom of the open pit model (101); A mining body component model (140) is disposed in the test box (110) and contacts the bottom of the boundary pillar model (130) to support the boundary pillar model (130); The conveying assembly (200) comprises: A protective shell (210) is disposed on the test box (110) and has a bottom formed with a plurality of drop openings (201) that communicate with the open pit model (101); A drive shaft (220) is coaxially rotatably mounted in the protective shell (210); The blocking plates (230) are staggered and fixedly arranged on the driving shaft (220), and when the blocking plates (230) are in contact with the blanking opening (201), the blocking plates (230) block the blanking opening (201); A material storage assembly (240) is in communication with the protective shell (210) and is used to transport tailings into the protective shell (210); A vibration component (250) is provided on the outer wall of the test box (110) and is used to evenly spread the tailings in the open pit model (101).

2. The test device for induced boundary pillar destruction in an open pit with tailings backfill as claimed in claim 1, characterized in that: The mining volume component model (140) includes: A plurality of first mining bodies (141) are arranged in parallel in the test box (110) and are in contact with the bottom of the boundary pillar model (130); The second mining body (142) is arranged between the adjacent first mining bodies (141) and is in contact with the bottom of the boundary pillar model (130).

3. The test device for induced boundary pillar destruction in an open pit with tailings backfill as claimed in claim 1, characterized in that: The material storage component (240) includes: A storage box (241) for storing tailings; A delivery pipe (242) connected between the storage box (241) and the protective shell (210); The auger (243) is arranged in the conveying pipe (242) and is used to convey the tailings.

4. The test device for induced boundary pillar destruction in an open pit with tailings backfill as claimed in claim 1, characterized in that: The monitoring component (400) includes: A fiber grating sensor (410) is arranged inside the boundary pillar model (130); A pressure sensor (420) is provided at the bottom of the mining body component model (140); A plurality of acoustic emission probes (430) are equidistantly arranged on one side of the test box (110); The thermal infrared camera (440) is equidistantly arranged on the other side of the test box (110).

5. The test device for induced boundary pillar destruction in an open pit with tailings backfill as claimed in claim 1, characterized in that: The pressure control assembly (300) comprises: Hydraulic cylinder (310); A pressure plate (320) is provided on the top of the test box (110) and is connected to the output end of the hydraulic cylinder (310) for changing the pressure in the open pit model (101).

6. A test method for the destruction of boundary pillars induced by backfilling an open pit with tailings, characterized in that: A test device for inducing boundary pillar destruction by backfilling an open pit with tailings as described in any one of claims 1 to 5: Producing a mining body component model (140), a boundary pillar model (130), and an open pit model (101) that are sequentially connected, wherein the mining body component model (140) includes a first mining body (141) and a second mining body (142) that are adjacently arranged; Evenly laying tailings in the open pit model (101) and compacting it, with a compaction degree of ≥90%, to form a filling model; Applying a vertical load to the filling model to obtain a compacted backfill model; After the first mining body (141) is removed and filled with a filling body, the second mining body (142) is removed. If the boundary pillar model (130) is not destroyed after mining, a static load is applied to the backfill model at a rate of 0.1 MPa / min until the boundary pillar model (130) is destroyed. At the same time, historical data of the boundary pillar model (130) is obtained and pre-processed to obtain processed data. Inputting the processed data into a hybrid deep learning model to obtain a trained hybrid deep learning model; Input real-time data into the trained hybrid deep learning model to obtain the pillar safety factor; When the safety factor of the pillar is 0.8≤<1.0, reduce the loading rate to 0.05MPa / min; When the safety factor of the pillar is less than 0.8, the static load on the backfill model is suspended; When the safety factor of the pillar is less than 0.5, the static load applied to the backfill model is stopped, an alarm is sounded, and the experimental data is saved.

7. The test method for induced boundary pillar destruction in an open pit with tailings backfill as claimed in claim 6, characterized in that: The steps of making the open pit model (101) and the boundary pillar model (130) further include: Barite powder, river sand, gypsum and water were mixed in a ratio of 1:4:1.25:1.25, and cast into an open pit model (101) of 1:100 or 1:200, and cured for 7 days to form; Barite powder, river sand, gypsum and water were mixed in a ratio of 1:3.75:1.5:1.25 to prepare a boundary pillar model (130), which was then buried in the open pit model (101) at a designated position after curing for 7 days.

8. The test method for induced boundary pillar destruction in an open pit backfilled with tailings as claimed in claim 7, characterized in that: The step of making the filling model also includes: Tailings, cement and water are mixed according to the mass ratio, wherein the cement content is 5%, 10% and 15%, the water-solid ratio is 0.2, and the tailings particle size is less than 2mm.

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