Servo continuous variable stiffness loading experiment system for dynamic disaster of deep coal and rock mass

Abstract

The invention discloses a deep coal and rock mass dynamic disaster servo continuous variable stiffness loading experiment system, and relates to the technical field of deep engineering dynamic disaster simulation. In order to solve the problem that servo and continuous variable stiffness loading are difficult to realize at the same time to truly simulate coal and rock mass dynamic disasters in the existing experimental equipment, the invention provides the following technical scheme: the device comprises an electro-hydraulic servo rock mechanics experimental system, an electromagnetic variable stiffness loader, a monitoring system and an electronic control system; the rock mechanics experiment system applies external load in a servo control loading mode; the electromagnetic variable stiffness loader comprises a loading rod and a bearing table; the monitoring system is used for monitoring the whole coal and rock mass dynamic disaster inoculation process in real time; the electronic control system can realize continuous automatic change of the rigidity of the coal and rock mass loading system. The servo continuous variable rigidity loading experiment system can quantitatively calculate the energy input to the coal and rock mass by the loading system and is suitable for automatic continuous variable rigidity loading in a deep engineering coal and rock mass stress environment.

Description

Technical Field

[0001] The present invention relates to the technical field of deep engineering dynamic disaster simulation, and particularly relates to a servo continuous variable stiffness loading experimental system for deep coal and rock mass dynamic disasters. Background Art

[0002] With the gradual depletion of surface and shallow mineral resources, deep mining has become an inevitable trend in mineral resource development. However, deep mining faces many challenges. Among them, high ground stress, complex geological conditions, and disturbances caused by mining activities are all important factors inducing dynamic disasters of coal and rock masses. These dynamic disasters, such as rock bursts, rock bursts, and mine tremors, not only threaten the lives of mining personnel but also seriously restrict the mining efficiency and safety of deep mineral resources.

[0003] At present, the scientific community has not fully grasped the occurrence mechanism of deep coal and rock mass dynamic disasters. Therefore, it is urgent to truly simulate the disaster-causing factors and environment in the laboratory environment in order to deeply study its occurrence mechanism. Mining activities are one of the main reasons for the occurrence of dynamic disasters of coal and rock masses. During the mining process, coal and rock masses are affected by stress redistribution, including the unloading of radial stress and the concentration of tangential stress. At the same time, the local stiffness of the surrounding rock also decreases. This stress redistribution and stiffness change provide conditions for the occurrence of dynamic disasters.

[0004] Although there are currently some experimental devices that attempt to simulate the mechanical environment of deep coal and rock mass dynamic disasters, these devices still have some deficiencies. For example, the energy storage device in some devices is directly connected to the external load application system, which may cause the experimental results to be affected by the stiffness of the external load application system, thus unable to accurately reflect the dynamic response of coal and rock masses under actual mining conditions. In addition, the design of the variable stiffness loading device is relatively complex, bulky, and expensive, and it is difficult to achieve continuous variable stiffness loading, which limits the accuracy and practicality of the experimental system for simulating the whole process of deep coal and rock mass dynamic disasters.

[0005] Therefore, in order to more deeply study the mechanism of deep coal and rock mass dynamic disasters and improve the safety and efficiency of the mining process, it is necessary to develop an experimental system that can truly simulate the whole process of deep coal and rock mass excavation and has independent functional modules. Summary of the Invention

[0006] The purpose of the present invention is to provide a servo continuous variable stiffness loading experimental system for deep coal and rock mass dynamic disasters to solve the problem that existing experimental equipment is difficult to simultaneously achieve servo and continuous variable stiffness loading to truly simulate the dynamic disasters of coal and rock masses.

[0007] The technical solution of the present invention to solve the above technical problems is as follows: A servo continuous variable stiffness loading experimental system for dynamic disasters of deep coal and rock masses, characterized in that it includes: an electro-hydraulic servo rock mechanics experimental system, a variable stiffness loader, a monitoring system, and an electronic control system. The bottom of the electro-hydraulic servo rock mechanics experimental system is connected to the variable stiffness loader. A rock specimen is arranged at the bottom of the variable stiffness loader, and a cushion block is provided at the bottom of the rock specimen. The electro-hydraulic servo rock mechanics experimental system is used as an external load power source, adopts a servo loading mechanism, and has an infinite stiffness, which will not affect the failure characteristics of coal and rock masses. The variable stiffness loader includes a loading rod connected to the electro-hydraulic servo rock mechanics experimental system and a bearing platform arranged at the bottom of the loading rod. An electromagnetic spring assembly is arranged between the loading rod and the bearing platform. The stiffness of the variable stiffness loader represents the stiffness of the coal and rock mass loading system, is connected to the electronic control system, and according to the relationship between the stress concentration of coal and rock masses caused by deep coal mine mining or excavation activities and the stiffness of the loading system, the magnitude and direction of the current in the conductive coil of the variable stiffness loader are changed through the electronic control system, so as to adaptively and continuously change the stiffness of the loading system. The monitoring system includes acoustic emission probes and high-speed cameras. A plurality of acoustic emission probes are fixed on the surface of the rock specimen. A liftable bracket is arranged on the side of the rock specimen, and a high-speed camera is arranged on the liftable bracket. The high-speed camera, the liftable bracket, the electro-hydraulic servo rock mechanics experimental system, the variable stiffness loader, and the acoustic emission probes are all communicatively connected to the electronic control system.

[0008] The rock mechanics experimental system applies an external load by means of servo control loading, and is sequentially connected to the variable stiffness loader, the rock specimen, and the cushion block; the variable stiffness loader includes a loading rod and a bearing platform, and an electromagnetic spring assembly is arranged between the loading rod and the bearing platform, including a high-strength magnet, a spring, a low magnetic permeability sleeve, and a coil; the monitoring system includes a plurality of acoustic emission probes fixed on the surface of the rock specimen and a high-speed camera installed on the liftable bracket on the side of the specimen, which is used to monitor the whole process of the occurrence of dynamic disasters of coal and rock masses in real time; the electronic control system is composed of electronic components and a program control system, and can program the control of the magnitude and direction of the current in the electromagnetic variable stiffness loader according to the functional relationship between the loading state and the local stiffness of the surrounding rock, so as to realize the continuous and automatic change of the stiffness of the coal and rock mass loading system, and overcome the deficiency that the traditional experimental equipment manually controls the stiffness of the loading system and thus misses the best variable stiffness loading opportunity.

[0009] High-speed cameras and acoustic emission cameras, as physical mechanics information monitoring systems, can obtain the full-process response of the dynamic disasters in coal and rock masses in real time from multiple angles. Then, according to the relationship between the loading relationship and stiffness, the electronic control system adjusts the magnitude and direction of the current in the energized coil of the variable stiffness system, thereby realizing adaptive variable stiffness loading. By equipping with physical mechanics information monitoring systems such as stress, strain, displacement, acoustic emission, and microseismicity, the full-process response of the dynamic disasters in coal and rock masses is obtained in real time from multiple angles to change the stiffness.

[0010] Preferably, the electromagnetic spring assembly includes a low-permeability sleeve, which is clamped in the load-bearing table groove at the top of the load-bearing table. The loading rod passes through the low-permeability sleeve and acts on the weight-bearing table, and a wire is sleeved outside the low-permeability sleeve.

[0011] Preferably, a lower magnet installed at the top of the load-bearing table is provided inside the wire, and an elastic member and an upper magnet are successively arranged on the top of the lower magnet; the weight-bearing table is installed between the upper magnet and the loading rod.

[0012] Preferably, a weight-bearing table is installed between the upper magnet and the loading rod.

[0013] Preferably, the electro-hydraulic servo rock mechanics experimental system includes a power system, a measurement system, a power control system, a testing machine frame, and a protective net.

[0014] Preferably, the power system includes a loading oil cylinder, which is connected to a pressure push head, and the pressure push head applies pressure to the loading rod; a servo valve is provided on the loading oil cylinder.

[0015] Preferably, the measurement system includes a load sensor arranged at the bottom of the loading rod and a displacement sensor arranged on the side of the rock specimen.

[0016] Preferably, the power control system includes a controller and a software system.

[0017] Preferably, an operating table is provided at the bottom of the variable stiffness loader, and a test switch is provided at the side end of the operating table.

[0018] The present invention has the following beneficial effects: Improve the flexibility and accuracy of the experiment: The system can realize the automatic continuous change of the stiffness of the loading system by adjusting the action form (waveform, magnitude, and direction) of the current in the energized coil. This design significantly improves the flexibility of the experiment, enabling researchers to easily adjust the experimental conditions according to experimental requirements. At the same time, since the system can accurately control the loading process, the accuracy and reliability of the experimental results can be ensured, providing strong support for in-depth research on the mechanism of dynamic disasters in coal and rock masses.

[0019] Achieve multi-angle comprehensive monitoring: The system integrates various monitoring means such as stress, strain, displacement, acoustic emission, and high-speed photography, realizing real-time, multi-angle comprehensive monitoring and observation of the gestation and occurrence process of coal and rock mass dynamic disasters. This comprehensive monitoring method helps to reveal the mechanical behavior and failure mode of coal and rock mass, providing a scientific basis for assessing disaster risks and formulating disaster prevention measures.

[0020] Simulate the real stress path and stiffness environment: The system can automatically and continuously adjust the system stiffness according to the stress concentration (loading) degree of coal and rock mass during deep mine mining or underground space excavation. This design enables the system to truly simulate the stress path and stiffness environment experienced by different types of dynamic disasters such as rock bursts, rock bursts, and mine tremors occurring in deep coal and rock mass, providing an important means for revealing the disaster mechanism.

[0021] Enhance the universality of the experimental device: Through the adaptive continuous variable stiffness system, the experimental device can automatically adjust the stiffness according to the change of the external load loading state and the local stiffness of the surrounding rock, without the need for manual judgment of the loading state; this automatic adjustment mechanism enhances the universality of the experimental device, making it applicable to the research of different types of coal and rock mass dynamic disasters.

[0022] Promote scientific research and engineering applications: The successful development of this experimental system not only provides strong experimental equipment support for scientific research, but also is expected to promote the progress and development of related engineering technologies. For example, in the fields of mine mining, underground space utilization, etc., this system is expected to provide important technical support and solutions for disaster prevention and mitigation, safety guarantee, etc. Description of the Drawings

[0023] Figure 1 It is a schematic structural diagram of the servo continuous variable stiffness loading experimental system for deep coal and rock mass dynamic disasters of the present invention; Figure 2 It is a schematic structural diagram of the variable stiffness loader of the servo continuous variable stiffness loading experimental system for deep coal and rock mass dynamic disasters of the present invention; Figure 3 It is a schematic internal structure diagram of the variable stiffness loader of the servo continuous variable stiffness loading experimental system for deep coal and rock mass dynamic disasters of the present invention; Figure 4 It is a schematic structural diagram of the acoustic emission probe of the servo continuous variable stiffness loading experimental system for deep coal and rock mass dynamic disasters of the present invention; Figures 1 to 4The reference numerals shown in the figures are respectively represented as: high-speed camera 1, liftable support 2, electro-hydraulic servo rock mechanics experiment system 3, loading cylinder 31, pressure push head 32, test switch 33, electronic control system 4, operation console 5, variable stiffness loader 6, loading rod 61, upper magnet 610, lower magnet 611, low magnetic permeability sleeve 612, wire 62, load-bearing platform 63, elastic member 64, nut 65, groove 66, load-bearing platform groove 67, weight-bearing platform 69, rock specimen 7, cushion block 8, acoustic emission probe 9. Specific embodiments

[0024] The technical solutions of the present invention will be described clearly and completely below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0025] Please refer to Figures 1-4 , this embodiment provides a servo continuous variable stiffness loading experiment system for dynamic disasters of deep coal and rock masses. The system aims to simulate the changes in stress and surrounding rock stiffness environment during the excavation of deep coal and rock masses, so as to deeply study the mechanism of dynamic disasters of coal and rock masses. The following is a detailed description of the experimental system.

[0026] The experimental system mainly consists of an operation console 5 and an electro-hydraulic servo rock mechanics experiment system 3. The operation console 5 serves as the support platform for the entire experimental system, and the electro-hydraulic servo rock mechanics experiment system 3 is provided on its top. The electro-hydraulic servo rock mechanics experiment system 3 is the core device for applying external loads, and it has key components such as a power system, a measurement system, a power control system, a testing machine frame, and a protective net. The power system includes a loading cylinder 31, which applies pressure to the loading rod 61 through a connecting pressure push head 32 to achieve the loading of the rock specimen 7. To ensure the accuracy and stability of the loading, a servo valve is provided on the loading cylinder 31 to achieve precise control of the pressure push head 32. The measurement system includes a load sensor provided at the bottom of the loading rod 61 and a displacement sensor provided on the side of the rock specimen 7. These sensors can monitor the load and displacement changes during the loading process in real time, providing an important basis for the collection and analysis of experimental data. The power control system includes a controller and a software system, which cooperate together to achieve precise control and data acquisition of the entire experimental system. The testing machine frame provides a stable support structure for the entire experimental system, and the protective net is used to protect the safety of experimental personnel and equipment.

[0027] At the bottom of the electro-hydraulic servo rock mechanics experimental system 3, a variable stiffness loader 6 is connected. The variable stiffness loader 6 is one of the key components of the experimental system. It can achieve continuous changes in the loading stiffness, thereby simulating the stiffness environment changes of deep coal rock masses during the excavation process. The variable stiffness loader 6 includes a loading rod 61 and a load-bearing platform 63, and an electromagnetic spring assembly is provided between them. The electromagnetic spring assembly includes a wire 62 sleeved on the loading rod 61. Inside the wire 62, a low magnetic permeability sleeve 612 is provided. The low magnetic permeability sleeve 612 is clamped in a load-bearing platform groove 67 at the top of the load-bearing platform 63. The loading rod 61 passes through the low magnetic permeability sleeve 612 and acts on the weight-bearing platform 69 to ensure stable current flow in the wire 62 and prevent the current from interfering with the loading rod 61 and other components. Inside the wire 62, a lower magnet 611 is provided. On the top of the lower magnet 611, an elastic member 64 and an upper magnet 610 are successively provided. The upper magnet 610 and the lower magnet 611 are connected by the elastic member 64. The elastic member 64 can adopt elastic parts such as springs to form the electromagnetic spring assembly. When current passes through the wire 62, a magnetic field force will be generated between the upper magnet 610 and the lower magnet 611. This magnetic field force acts together with the elastic force of the elastic member 64 to achieve stiffness adjustment of the loading rod 61.

[0028] To further enhance the stability and load-bearing capacity of the variable stiffness loader 6, a weight-bearing platform 69 is also installed between the upper magnet 610 and the loading rod 61. The weight-bearing platform 69 can disperse the load borne by the loading rod 61, thereby extending the service life of the loading rod 61 and improving the stability of the entire experimental system.

[0029] A cushion block 8 is provided at the bottom of the rock specimen 7. A plurality of acoustic emission probes 9 are fixed on the surface of the rock specimen 7. These acoustic emission probes 9 can monitor the internal crack activities and failure characteristics of the rock specimen 7 during the loading process in real time. The other side of the acoustic emission probe 9 is connected to the electronic control system 4 to transmit the monitoring data to a computer for analysis in real time.

[0030] To record the failure process of the rock specimen 7, the experimental system is also provided with a liftable bracket 2 and a high-speed camera 1. The liftable bracket 2 can adjust the height according to experimental requirements to fix the high-speed camera 1 at a suitable position on the lifting platform of the liftable bracket 2. By adjusting the height and angle of the lifting platform, the high-speed camera 1 can be directed at the rock specimen 7 for photography to capture detailed data on rock deformation and failure. The high-speed camera 1, the liftable bracket 2, the electro-hydraulic servo rock mechanics experimental system 3, the variable stiffness loader 6, and the acoustic emission probe 9 are all communicatively connected to the electronic control system 4 to achieve real-time data transmission and sharing.

[0031] Before the experiment starts, a comprehensive inspection of the experimental system is required. First, check whether there is any oil leakage or air leakage in the equipment, and whether all connection parts are tightened. Then, conduct a safety inspection to ensure that all safety devices, including the emergency stop button and limit switches, are in normal working condition. In addition, it is also necessary to verify that all remote control valves remain in the normally open state to ensure that in the event of power failure, gas cut-off, oil cut-off or other unexpected situations, the system can automatically respond and protect the safety of the experimenters and equipment.

[0032] After the inspection is completed, start assembling the variable stiffness loader 6. First, fix the lower magnet 611 with five nuts 65, which are located at the four corners and the exact middle position of the magnet. At the same time, connect austenitic stainless steel high-strength springs at the corresponding positions, and these springs are arranged in the middle of the circular magnet groove 68 on the lower magnet 611. Place the lower magnet 611 exactly in the middle of the groove 66 on the load-bearing platform 63, and use the other side of the nut 65 to tightly connect it to the load-bearing platform 63. Next, for the upper magnet 610 of the same size as the lower magnet 611, also connect five high-strength springs correspondingly in the circular magnet groove 68, and fix them with nuts 65 at the four corners and the middle position of the upper magnet 610. Then, place the load-bearing platform 69, which is slightly smaller than the upper magnet 610, exactly in the middle of the upper magnet, and connect it at the midpoints of the four sides of the load-bearing platform through nuts 65. At the same time, weld the loading rod 61 to the load-bearing platform 69 to form a complete loading structure. Finally, cover the low magnetic permeability sleeve 612 to ensure that it fits with the groove 67 of the load-bearing platform, and wind the wire 62 along the low magnetic permeability sleeve 612. Connect the other end of the wire 62 to the electronic control system 4 to complete the overall assembly of the variable stiffness loader 6.

[0033] Place the assembled variable stiffness loader 6 on the loading platform of the electro-hydraulic servo rock mechanics experimental system 3. Fix a ring of acoustic emission probes 9 on the rock specimen 7, and connect the other side of the acoustic emission probes to the electronic control system 4. Then, place the rock specimen 7 directly below the variable stiffness loader 6, and place a cushion block 8 below it. Adjust the height of the liftable high-speed camera support 2 to an appropriate distance, and fix the high-speed camera 1 on the lift table of the support. By adjusting the height and angle of the lift table, make the high-speed camera 1 face the rock specimen 7 for photography in order to capture detailed data on the deformation and failure of the rock.

[0034] After all the preparations are ready, the experiment begins. First, start the power system of the electro-hydraulic servo rock mechanics experiment system 3, and apply pressure to the loading rod 61 through the loading cylinder 31 and the pressure push head 32. During the loading process, the measurement system monitors the load and displacement changes in real time and transmits the data to the electronic control system 4 for analysis. At the same time, the acoustic emission probe 9 monitors the crack activities and failure characteristics inside the rock specimen 7 in real time and transmits the data to the computer in real time. The high-speed camera 1 captures the failure images of the rock specimen 7 in real time, providing an important basis for the collection and analysis of experimental data.

[0035] During the experiment, the form of the current supplied to the variable stiffness loader 6 is adjusted through the electronic control system 4 to change its stiffness. The electronic control system 4 can set different current waveforms, magnitudes, and directions according to the experimental requirements, thereby realizing continuous adjustment of the stiffness of the loading system. This design breaks through the limitation that traditional loading equipment can only achieve a single specific stiffness in each experiment, making the stress path and energy analysis of the dynamic failure process of coal and rock masses more clear and quantitative.

[0036] By comprehensively using monitoring devices such as stress, strain, displacement, acoustic emission, and high-speed photography, the experiment can capture the key physical and mechanical information of coal and rock masses during the loading process in real time. The stress monitoring device records the stress changes of coal and rock masses in real time, revealing their mechanical behaviors and failure modes; the strain data reflects the deformation degree of coal and rock masses, revealing their elastic and plastic deformation characteristics; the displacement monitoring device records the displacement changes of coal and rock masses, analyzing their stability and predicting the failure location; the acoustic emission technology captures the formation and propagation of internal microcracks, monitors crack activities, evaluates failure characteristics, and provides real-time warnings; the high-speed camera records the dynamic process of rock failure, including the formation and propagation of cracks until the ejection of coal and rock fragments during dynamic disasters such as rock bursts finally occurs.

[0037] The core advantage of this experimental system is that it can realize the automatic continuous change of the stiffness of the loading system by adjusting the form of the current (waveform, magnitude, and direction) in the energized coil. This design not only improves the flexibility of the experiment but also simplifies the system structure, providing an efficient and accurate solution for the variable stiffness requirements in engineering applications. At the same time, by constructing a physical and mechanical information monitoring system integrating monitoring means such as stress, strain, displacement, acoustic emission, and high-speed photography, real-time, multi-angle, and comprehensive monitoring and observation of the gestation and occurrence process of coal and rock mass dynamic disasters are realized, providing scientific data for revealing the mechanisms of different types of deep coal and rock mass dynamic disasters.

[0038] In addition, the system can automatically and continuously adjust the stiffness of the loading system (surrounding rock) according to the correlation between the external load loading state and the change in the local stiffness of the surrounding rock. Specifically, the excavation operation will cause stress concentration and a decrease in the stiffness of the surrounding rock. Based on the functional relationship between the stress state (concentration degree) of coal and rock mass and the stiffness of the surrounding rock revealed by previous research, this system realizes the above corresponding functional relationship in physical experiments by programmatically controlling the action form of the current in the energized coil, that is, it realizes the function of adaptive continuous variable stiffness of the loading system. In this way, the system can determine when to adjust the stiffness without manual judgment of the loading state, thus overcoming the deficiencies existing in the prior art.

[0039] This experimental system can automatically and continuously adjust the system stiffness according to the stress concentration (loading) degree of coal and rock mass during deep mine exploitation or underground space excavation, so as to truly simulate the stress paths and stiffness environments experienced by different types of dynamic disasters such as rock bursts, rock bursts, and mine tremors occurring in deep coal and rock masses. This technology breaks through the limitation that traditional devices need to manually judge the loading state and the timing of stiffness change, realizes the accurate simulation of the gestation and occurrence processes of different types of coal and rock mass dynamic disasters, and makes the developed experimental device more universal. Through the above-mentioned adaptive continuous variable stiffness system, different types of dynamic disasters of deep coal and rock masses can be reproduced more accurately under controllable laboratory variable conditions, providing strong experimental equipment support for the study of the mechanism of deep coal and rock mass dynamic disasters.

[0040] In summary, the servo continuous variable stiffness loading experimental system for deep coal and rock mass dynamic disasters provided by this embodiment realizes the real-time and multi-angle comprehensive monitoring and observation of the gestation and occurrence processes of deep coal and rock mass dynamic disasters by using key components and monitoring equipment such as an electro-hydraulic servo rock mechanics experimental system, a variable stiffness loader, an acoustic emission probe, and a high-speed camera.

[0041] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A servo continuous variable stiffness loading experimental system for dynamic disasters of deep coal rock mass, characterized in that Comprising: An electro-hydraulic servo rock mechanics experimental system (3), a variable stiffness loader (6), a monitoring system, and an electronic control system (4). The bottom of the electro-hydraulic servo rock mechanics experimental system (3) is connected to the variable stiffness loader (6). A rock specimen (7) is provided at the bottom of the variable stiffness loader (6), and a cushion block (8) is provided at the bottom of the rock specimen (7). The electro-hydraulic servo rock mechanics experimental system (3) is used as an external load power source. The variable stiffness loader (6) includes a loading rod (61) connected to the electro-hydraulic servo rock mechanics experimental system (3) and a load-bearing platform (63) provided at the bottom of the loading rod (61). An electromagnetic spring assembly is provided between the loading rod (61) and the load-bearing platform (63). The variable stiffness loader (6) is connected to the electronic control system (4). By changing the magnitude and direction of the current in the conductive coil of the variable stiffness loader (6) through the electronic control system (4), the stiffness of the loading system can be continuously and adaptively changed. The monitoring system includes acoustic emission probes (9) and a high-speed camera (1). A plurality of the acoustic emission probes (9) are fixed on the surface of the rock specimen (7). A liftable bracket (2) is provided on the side of the rock specimen (7), and the high-speed camera (1) is provided on the liftable bracket (2). The high-speed camera (1), the liftable bracket (2), the electro-hydraulic servo rock mechanics experimental system (3), the variable stiffness loader (6), and the acoustic emission probes (9) are all communicatively connected to the electronic control system (4).

2. The servo continuous variable stiffness loading experimental system for dynamic disasters of deep coal rock mass according to claim 1, wherein The electromagnetic spring assembly includes a low magnetic permeability sleeve (612). The low magnetic permeability sleeve (612) is clamped in a load-bearing platform groove (67) at the top of the load-bearing platform (63). The loading rod (61) passes through the low magnetic permeability sleeve (612) and acts on the load-bearing platform (69). A wire (62) is sleeved outside the low magnetic permeability sleeve (612).

3. The servo continuous variable stiffness loading experimental system for dynamic disasters of deep coal and rock masses according to claim 2, wherein Inside the wire (62), a lower magnet (611) installed at the top of the load-bearing platform (63) is provided. An elastic member (64) and an upper magnet (610) are sequentially provided on the top of the lower magnet (611). The load-bearing platform (69) is installed between the upper magnet (610) and the loading rod (61).

4. The servo continuous variable stiffness loading experimental system for dynamic disasters of deep coal rock mass according to claim 1, characterized in that The electro-hydraulic servo rock mechanics experimental system (3) includes a power system, a measurement system, a power control system, a testing machine frame, and a protective net.

5. The servo continuous variable stiffness loading experimental system for dynamic disasters of deep coal rock mass according to claim 4, wherein The power system includes a loading oil cylinder (31). The loading oil cylinder (31) is connected to a pressure push head (32), and the pressure push head (32) applies pressure to the loading rod (61). A servo valve is provided on the loading oil cylinder (31).

6. The servo continuous variable stiffness loading experimental system for dynamic disasters of deep coal rock mass according to claim 4, wherein The measurement system includes a load sensor provided at the bottom of the loading rod (61) and a displacement sensor provided on the side of the rock specimen (7).

7. The servo continuous variable stiffness loading experimental system for dynamic disasters of deep coal rock mass according to claim 4, wherein The power control system includes a controller and a software system.

8. The servo continuous variable stiffness loading experimental system for dynamic disasters of deep coal rock mass according to claim 1, characterized in that An operation table (5) is provided at the bottom of the variable stiffness loader (6), and a test switch (33) is provided at the side end of the operation table (5).

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