Liquid filling device for Hopkinson bar experimental equipment

Abstract

The invention relates to the technical field of Hopkinson bar experiments, in particular to a liquid filling device for Hopkinson bar experimental equipment, which comprises a liquid filling cylinder and a height-adjustable support seat, the liquid filling cylinder comprises a liquid filling ring with a liquid filling port, two axial sides of the liquid filling ring are respectively connected with a connecting pipe, the connecting pipe and the liquid filling ring are coaxial, and the height of the liquid filling ring is adjustable. The connecting pipe is of a conical reducing structure, the large-diameter end of the connecting pipe is detachably connected with the liquid filling ring, the small-diameter end of the connecting pipe clamps a rock sample, and a support used for supporting the rock sample is arranged in the liquid filling ring. A clamping connecting assembly used for applying clamping force to the small-caliber end of the connecting pipe and connecting the liquid filling barrel with the height-adjustable supporting seat is arranged outside the small-caliber end of the connecting pipe, and a hydraulic sensor is arranged in the liquid filling ring. In the high strain rate loading process of the Hopkinson bar experiment, stable, closed and controllable liquid filling can be performed on the internal fracture area of the sample, so that the dynamic response research on the water-containing fractured rock mass is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of Hopkinson bar experiment, and particularly to a liquid filling device for a Hopkinson bar experiment device. Background Art

[0002] As an experimental method for testing the mechanical properties of materials under dynamic loads, the Hopkinson bar experimental device mainly includes an emission system, a bar system (impact bar, incident bar, transmission bar and absorption bar), a data acquisition system (strain gauge, oscilloscope, ultra-dynamic strain gauge) and a damping absorption system, and is mostly used for measuring the stress-strain relationship of specimens at high strain rates. The traditional Hopkinson bar experimental system is mostly used for the dynamic characteristic research of rock specimens in a dry state. However, under long-term geological action, deep liquid-filled rock fractures are widespread in nature. In engineering practices such as geotechnical engineering, underground tunnels, hydropower projects, and coalbed methane extraction, water-containing fracture structures inevitably exist in geological structures. When the structure is subjected to strong loads such as blasting and earthquakes, the water-containing fractures have a profound impact on the mechanical properties of the structure, seriously affecting the stability of engineering rock masses. Therefore, understanding the basic law of stress wave propagation in water-containing fractured rock masses is crucial for predicting and evaluating the safety of rock mass engineering. With the in-depth study of related research, there is an urgent need for a feasible experimental device for studying the dynamic response of liquid-filled rock fractures at high strain rates.

[0003] Although a large number of studies have focused on the dynamic response of dry fractured rock masses, the experimental research methods for the response mechanism under saturated or liquid-filled conditions are still relatively limited. Under high strain rate loading, the traditional experimental device is difficult to achieve in-situ liquid injection, sealing protection and loading synchronous control during the dynamic loading process of the specimen. The lack of a controllable liquid injection device not only reduces the experimental repeatability, but also limits the in-depth study of the fracture seepage coupling effect. At present, in the research on the propagation characteristics of stress waves in water-containing fractures, organic glass tubes and epoxy resin glue are mostly used to make liquid-filled fracture specimens. Two parts of rock samples are connected through the organic glass tube (a suitable spacing is left between the rock samples for liquid filling), and the rock samples and the organic glass tube are bonded with epoxy resin glue, and liquid is filled through the water injection holes on the organic glass tube to form a water-containing fractured rock specimen.

[0004] However, the above method for preparing the liquid-filled crack specimen has the following defects: 1. The stiffness of the plexiglass tube is lower than that of the rock sample. During the impact experiment using the Hopkinson bar device, cracking or deformation of the tube wall will occur, seriously affecting the accuracy of the experimental data. 2. Cracks and bubbles are easily generated during the curing process of the epoxy resin, resulting in leakage of the liquid inside the tube and thus affecting the experimental results. 3. The epoxy resin glue will displace during the curing process, and thus it is impossible to ensure that the crack spacing reaches the preset value, and the regulation accuracy is low. 4. A permanent connection is formed between the rock sample and the plexiglass tube using the epoxy resin glue, which is difficult to disassemble and reuse after one experiment, resulting in a large experimental loss and high cost. Summary of the Invention

[0005] The object of the present invention is to provide a liquid filling device for Hopkinson bar experimental equipment in view of the deficiencies of the prior art, which can stably, hermetically and controllably fill the liquid into the crack area inside the specimen during the high strain rate loading experiment (such as the split Hopkinson bar experiment) to realize the dynamic response research of the water-containing fractured rock mass and solve the problems existing in the above prior art.

[0006] To achieve the above object, the present invention adopts the following technical solutions: A liquid filling device for Hopkinson bar experimental equipment includes a liquid filling cylinder body and a height-adjustable support seat for supporting the liquid filling cylinder body. The liquid filling cylinder body includes a liquid filling ring provided with a liquid filling port. Connecting pipes are respectively connected to both axial sides of the liquid filling ring. The connecting pipes are coaxial with the liquid filling ring. The connecting pipes are of a tapered structure. The large-diameter end of the connecting pipe is detachably connected to the liquid filling ring. The small-diameter end of the connecting pipe is a clamping end for clamping one end of the rock sample. A support for supporting the other end of the rock sample is provided inside the liquid filling ring. A clamping connection assembly for applying a clamping force to the outside of the small-diameter end of the connecting pipe is provided. A hydraulic sensor is provided inside the liquid filling ring.

[0007] Further, the height-adjustable support seat includes a base and a support plate. A lifting assembly for driving the support plate to lift is provided on the base.

[0008] Furthermore, the lifting assembly includes two scissor mechanisms correspondingly arranged below the small-diameter end of the connecting pipe. The scissor mechanism includes a lower connecting groove arranged above the base, an upper connecting groove arranged below the support plate, a first support rod, and a second support rod. One end of the first support rod is rotatably connected to one end of the lower connecting groove, and the other end of the first support rod is rotatably connected with a first sliding member. A first sliding groove is correspondingly formed in the upper connecting groove, and the first sliding member is slidably connected with the first sliding groove. One end of the second support rod is rotatably connected to one end of the upper connecting groove, and the other end of the second support rod is rotatably connected with a second sliding member. A second sliding groove is correspondingly formed in the lower connecting groove, and the second sliding member is slidably connected with the second sliding groove. The middle part of the first support rod is rotatably connected to the middle part of the second support rod. The lifting assembly further includes a driving mechanism for driving the first sliding member and the second sliding member in the two scissor mechanisms to slide horizontally synchronously.

[0009] Furthermore, the driving mechanism includes two fixed seats arranged above the base. A trapezoidal lead screw is rotatably connected to the fixed seats. A nut seat is threadedly connected between the two fixed seats on the trapezoidal lead screw. The nut seat is horizontally connected with a connecting rod. The horizontal two ends of the connecting rod are respectively connected with a second sliding member. A convex block is arranged below the nut seat, and a guide groove is correspondingly formed in the base. The convex block is slidably connected in the guide groove. A rotating handle is connected to the trapezoidal lead screw.

[0010] Furthermore, the detachable connection structure between the large-diameter end of the connecting pipe and the liquid filling ring includes a flange. A first through hole is correspondingly formed in the large-diameter end of the connecting pipe, and a second through hole is formed in the liquid filling ring. Both sides of the connecting pipe are bolted to the inner liquid filling ring through the flange.

[0011] Furthermore, a ball is movably connected to the end of the bracket, and the ball abuts against the rock sample.

[0012] Furthermore, the clamping connection assembly includes a lower bolt seat arranged on the support plate, and an upper bolt cover is bolted to the lower bolt seat in the vertical direction.

[0013] Furthermore, a limiting block is arranged at the bottom of the liquid filling ring, and a limiting groove is correspondingly formed in the support plate.

[0014] Furthermore, a vertical rod is extended and arranged on the base in the vertical direction, and the support plate is slidably connected with the vertical rod in the vertical direction.

[0015] Compared with the prior art, the liquid filling device proposed by the present invention, which is cooperatively carried on the Hopkinson bar experimental device, provides a technical solution with a compact structure, simple operation, and strong repeatability for the core technical problem that it is currently difficult to realize the dynamic response test of fractured rock mass in a liquid-containing state in a split Hopkinson bar (SHPB) system, and has the following beneficial effects and application values: 1. Improved sealing performance: The present invention uses high-strength bolts to tightly connect the liquid-filled ring, connecting pipe, and flange to construct a closed liquid-filled cavity, which can maintain the overall structural stability of the device under high strain rate impacts of 10 2 s -1 to 10 4 s -1 and effectively prevent liquid leakage. Compared with the traditional one-time sealing method that relies on organic glass tubes and epoxy resin bonding, it has higher sealing performance, repeatability, and structural toughness.

[0016] 2. Dynamic liquid-filled crack construction ability: The device can quickly construct liquid-filled cracks by clamping the rock sample at the small-diameter end of the connecting pipe. The crack width can be adjusted in the range of 0 - 10 mm, supporting the simulation of water-rock coupling states at different scales, and users can quickly and arbitrarily adjust according to experimental requirements.

[0017] 3. Support for synchronous multi-physical field testing: The device integrates a hydraulic sensor and a mechanical acquisition module of the Hopkinson bar device, and can simultaneously obtain the crack pressure evolution curve and the dynamic stress-strain response curve to meet the needs of multi-parameter correlation analysis.

[0018] 4. Realistic mechanical simulation: The present invention designs four brackets with balls inside the liquid-filled ring to support the rock sample and allow it to generate free micro-displacements in the loading direction, thereby reducing the interference of dispersion waves caused by clamping, more realistically reflecting the stress and deformation behavior of the rock sample in the natural environment, and improving the geological reducibility of the test simulation.

[0019] 5. Size adaptability and height adjustment ability: The height-adjustable support base in the present invention not only carries the clamping and connecting components for clamping and connecting functions, but also can adjust the height of the support plate through the lifting component, so that the rock sample is in coaxial alignment while being closely attached to the impact rod and incident rod, greatly improving the versatility and module adaptability of the experimental device.

[0020] 6. Structure disassembly, economy, and environmental protection: The present invention adopts a split and detachable design, and each component can be independently replaced, disassembled, and cleaned. Compared with the one-time encapsulation means such as epoxy resin glue used in traditional test methods, the present invention has a function of repeated use in structure, not only reducing sample loss and material waste, but also greatly improving experimental efficiency and resource utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic diagram of the overall structure of a liquid-filled device for a Hopkinson bar experimental equipment provided by the present invention; Figure 2 is a right view of a liquid-filled device for a Hopkinson bar experimental equipment provided by the present invention; Figure 3Schematic diagram of the overall structure of the liquid filling cylinder in a liquid filling device for a Hopkinson bar experimental device provided by the present invention; Figure 4 Exploded view of the liquid filling cylinder in a liquid filling device for a Hopkinson bar experimental device provided by the present invention; Figure 5 Schematic diagram of the structure of the liquid filling ring in a liquid filling device for a Hopkinson bar experimental device provided by the present invention; Figure 6 Schematic diagram of the structure of the lifting assembly in a liquid filling device for a Hopkinson bar experimental device provided by the present invention; Figure 7 Schematic diagram of the structure of the nut seat in a liquid filling device for a Hopkinson bar experimental device provided by the present invention.

[0022] Among them, the reference numerals are: 1. Liquid filling cylinder; 11. Connecting pipe; 111. First through hole; 12. Liquid filling ring; 121. Second through hole; 122. Limiting block; 13. Liquid filling port; 14. Support; 15. Ball; 16. Flange; 2. Height-adjustable support base; 21. Base; 211. Lower connection groove; 212. Second chute; 213. Guide groove; 22. Support plate; 221. Upper connection groove; 222. First chute; 23. First support rod; 231. First sliding member; 24. Second support rod; 241. Second sliding member; 25. Fixed seat; 26. Trapezoidal lead screw; 27. Nut seat; 28. Connecting rod; 29. Rotating handle; 201. Convex block; 202. Vertical rod; 3. Clamping connection assembly; 31. Lower bolt seat; 32. Upper bolt cover. Detailed implementation manners

[0023] In order to enable those skilled in the art of the present technology to better understand the solution of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0024] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0025] It should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0026] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features.

[0027] For ease of understanding, please refer to Figures 1 to 5, this embodiment provides a liquid filling device for a Hopkinson bar experimental device, which includes a liquid filling cylinder body 1 and a height adjustable support base 2 located below the liquid filling cylinder body 1. The height adjustable support base 2 is used to support the liquid filling cylinder body 1. The liquid filling cylinder body 1 includes two connecting pipes 11 and a liquid filling ring 12 located between the two connecting pipes 11. The two connecting pipes 11 are coaxial with the liquid filling ring 12 in the horizontal direction. A liquid filling port 13 is opened on the liquid filling ring 12, and liquid (water or oil) is injected into the interior of the liquid filling cylinder body 1 through the liquid filling port 13. The connecting pipe 11 is of a tapered structure, its large diameter end is bolted to the liquid filling ring 12, and the small diameter end is a clamping end for clamping the end of the rock sample on the horizontal side. Four supports 14 for supporting the other end of the rock sample are provided inside the liquid filling ring 12. One end of the rock sample is clamped by the connecting pipe 11, and the other end of the rock sample extends into the liquid filling ring 12 and abuts against two of the supports 14 to ensure that the rock sample remains horizontal after installation. Ball bearings 15 are movably connected to the ends of the supports 14, and the ball bearings 15 abut against the rock sample. The friction between the rock sample and the supports 14 is reduced through the ball bearings 15, thereby reducing the interference of the dispersive wave generated by clamping and reflecting the behavior of the rock sample under force and deformation in the natural environment. Specifically, the large diameter end of the connecting pipe 11 abuts against the flange 16 in the horizontal direction. A plurality of horizontally arranged first through holes 111 are opened at the large diameter end of the connecting pipe 11, and a plurality of horizontally arranged second through holes 121 are opened on the liquid filling ring 12. The relative fixation of the two connecting pipes 11 and the liquid filling ring 12 is realized by sequentially passing a plurality of long bolts through the left flange 16, the first through holes 111 at the large diameter end of the left connecting pipe 11, the second through holes 121 of the liquid filling ring 12, the first through holes 111 at the large diameter end of the right connecting pipe 11, and the right flange 16. A clamping connection assembly 3 is provided outside the small diameter end of the connecting pipe 11. The clamping connection assembly 3 can connect the liquid filling cylinder body 1 and the height adjustable support base 2 to each other to realize their relative fixation. At the same time, a clamping force can be applied to the small diameter end of the connecting pipe 11, and then a clamping force is applied to the rock sample through the small diameter end of the connecting pipe 11. After ensuring that the two rock samples are stably clamped at the small diameter ends of the two connecting pipes 11, a closed liquid filling space is formed inside the liquid filling cylinder body 1 to avoid water seepage during the experiment. Specifically, the two clamping connection assemblies 3 respectively include a lower bolt seat 31 and an upper bolt cover 32. The lower bolt seat 31 is fixedly arranged on the height adjustable support base 2. The inner wall of the lower bolt seat 31 abuts against the outer wall of the small diameter end of the connecting pipe 11. The lower bolt seat 31 is bolted to the upper bolt cover 32 in the vertical direction. A hydraulic sensor is installed inside the liquid filling ring 12. The hydraulic sensor is used to record in real time the pressure signal generated by the liquid inside the liquid filling cylinder body 1 on the rock sample.Preferably, the liquid filling ring 12 and the two flange plates 16 are both made of high-strength titanium alloy steel, and the connecting pipe 11 is a wire-reinforced polyurethane hose; the inner diameter of the small-diameter end of the connecting pipe 11 is slightly smaller than the outer diameter of the rock sample. That is, after the rock sample is inserted into the small-diameter end of the connecting pipe 11 from the large-diameter end of the connecting pipe 11, the small-diameter end of the connecting pipe 11 will squeeze and clamp the rock sample; the inner diameter of the circle formed by the lower bolt seat 31 and the upper bolt cover 32 is slightly smaller than the inner diameter of the small-diameter end of the connecting pipe 11, ensuring that while providing stable clamping for the small-diameter end of the connecting pipe 11 to prevent water seepage, it also avoids structural deformation at the small-diameter end of the connecting pipe 11 due to excessive clamping force.

[0028] The staff horizontally clamp and install the two rock samples on the small-diameter ends of the connecting pipes 11 on both sides respectively, and achieve the relative fixation of the connecting pipes 11 on both sides and the liquid filling ring 12 through bolt connection, forming a sealed cavity inside the liquid filling cylinder 1. Then, the outer end faces of the two rock samples are respectively in close contact with the incident bar and the transmission bar in the Hopkinson bar experimental device to ensure the effective transmission of force between the rock sample and the incident bar and the transmission bar. After that, a predetermined volume of liquid (water or oil) is injected into the sealed cavity through the liquid filling port 13 on the liquid filling ring 12, so that the liquid completely fills the gap area between the two rock samples, thereby simulating the rock sample structure with controllable water-containing fractures.

[0029] For ease of understanding, please continue to refer to Figures 1 to 6, the height-adjustable support base 2 includes a base 21 and a support plate 22 located above the base 21. A lifting assembly is provided on the base 21, and the lifting assembly is used to drive the support plate 22 to vertically lift and lower. The lifting assembly specifically includes two scissor mechanisms and a driving mechanism. The scissor mechanisms are respectively located below the small-diameter ends of the two connecting pipes 11. Specifically, it includes a lower connecting groove 211 horizontally and longitudinally fixed above the base 21, an upper connecting groove 221 horizontally and longitudinally fixed below the height-adjustable support base 2, a first support rod 23, and a second support rod 24. A horizontally transverse first sliding groove 222 is formed at the front end of the upper connecting groove 221, and a horizontally transverse second sliding groove 212 is formed at the front end of the lower connecting groove 211. The rear end of the first support rod 23 is rotatably connected to the rear end of the lower connecting groove 211, the front end of the first support rod 23 is rotatably connected to a first sliding member 231, and the first sliding member 231 is slidably connected in the first sliding groove 222. The rear end of the second support rod 24 is rotatably connected to the rear end of the upper connecting groove 221, the front end of the second support rod 24 is rotatably connected to a second sliding member 241, and the second sliding member 241 is slidably connected in the second sliding groove 212. The middle of the first support rod 23 is rotatably connected to the middle of the second support rod 24. The staff drives the second sliding members 241 in the two scissor mechanisms to horizontally and longitudinally slide in the corresponding second sliding grooves 212 respectively through the driving mechanism, drives the corresponding first sliding members 231 to horizontally and longitudinally slide synchronously in the first sliding grooves 222, and further drives the support plate 22 to vertically lift and lower. Specifically, when the driving mechanism drives the second sliding members 241 in the two scissor mechanisms to slide from front to back in the second sliding grooves 212 respectively, the support plate 22 vertically rises; when the driving mechanism drives the second sliding members 241 in the two scissor mechanisms to slide from back to front in the second sliding grooves 212 respectively, the support plate 22 vertically descends. In the initial state (that is, the distance between the support plate 22 and the base 21 is the smallest), both first sliding members 231 are located at the frontmost end of the first sliding groove 222, both second sliding members 241 are located at the frontmost end of the second sliding groove 212, and the two lower bolt seats 31 are in a horizontally transverse coaxial position.

[0030] For ease of understanding, please continue to refer to Figures 1 to 7, the driving mechanism includes two fixed seats 25 fixedly arranged on the base 21 at horizontal and longitudinal intervals respectively. The trapezoidal lead screw 26 extends horizontally and longitudinally through the two fixed seats 25 and is rotatably connected to the fixed seats 25. The nut seat 27 is arranged between the two fixed seats 25 and is threadedly connected to the trapezoidal lead screw 26. A convex block 201 is fixedly arranged below the nut seat 27. Correspondingly, a horizontally longitudinal guide groove 213 is formed in the base 21. The convex block 201 is slidably connected in the guide groove 213. The nut seat 27 extends outward and is fixedly provided with connecting rods 28 on both horizontal and transverse sides respectively. The two connecting rods 28 are respectively fixedly connected to the second sliding members 241 on both sides. The rotating handle 29 is fixedly connected to the front end of the trapezoidal lead screw 26. The lead angle of the trapezoidal lead screw 26 is smaller than the static friction angle, so that the frictional force between the trapezoidal lead screw 26 and the nut seat 27 is sufficient to prevent reverse movement, that is, self-locking can be achieved. The staff rotates the rotating handle 29 to drive the trapezoidal lead screw 26 to rotate, and then drives the nut seat 27 to translate along the direction of the guide groove 213. Finally, the second sliding member 241 is driven to slide horizontally and longitudinally in the second chute 212 through the translation of the connecting rods 28 fixed on both sides of the nut seat 27. After the lifting action of the support plate 22 is completed, the trapezoidal lead screw 26 can be position-locked to avoid the reverse movement of the trapezoidal lead screw 26 and the nut seat 27 driven by the self-weight of the liquid-filled cylinder 1 and the scissor mechanism, thereby avoiding the automatic falling of the support plate 22 and the failure of the function of the lifting assembly.

[0031] For easy understanding, please continue to refer to Figures 1 to 7 , eight vertical rods 202 are extended and arranged on the base 21 in the vertical direction, respectively located around the two scissor mechanisms. The support plate 22 is slidably connected to all the vertical rods 202 in the vertical direction to ensure the synchronous movement of the two scissor mechanisms on both sides, and further ensure that the support plate 22 always remains horizontal before and after lifting. A limit block 122 is arranged at the bottom of the liquid-filled ring 12. Correspondingly, a limit groove is formed in the middle of the support plate 22. By the corresponding positions of the limit block 122 and the limit groove, it is convenient for the staff to install and align the liquid-filled cylinder 1. Just place the limit block 122 below the liquid-filled cylinder 1 corresponding to the position of the limit groove, and the small-diameter ends of the two connecting pipes 11 can be installed on the lower bolt seat 31. At the same time, the liquid filling port 13 is vertically upward, which is convenient for the staff to perform the liquid filling operation.

[0032] The usage method of the present invention: 1. Component inspection: Inspect the key components of the Hopkinson bar experimental device and the liquid filling device, including the launch system, rod system (impact rod, incident rod, transmission rod and absorption rod), data acquisition system (strain gauge, oscilloscope, ultra-dynamic strain gauge) and damping absorption system in the Hopkinson bar experimental device, as well as components such as the connecting pipe 11, lifting assembly, flange 16 and liquid-filled ring 12 of the liquid filling device, to ensure that there are no cracks, aging, leakage or other defects affecting the experimental performance on the surfaces of the above components and they are in a state where they can work normally.

[0033] 2. Rock sample installation and fracture spacing adjustment: The axial length of the liquid filling ring 12 is 20 mm, and the axial lengths of the two connecting pipes 11 are both 40 mm. That is, after installing the liquid filling ring 12 and the two connecting pipes 11, the axial length of the liquid filling cylinder body 1 formed is 100 mm. Take two rock samples to be tested with an axial length of 50 mm, and insert the two rock samples from the large-diameter end of the connecting pipe 11 into the small-diameter end until one end face of the rock sample is flush with the small-diameter end face of the connecting pipe 11. At this time, after bolting the two connecting pipes 11 holding the rock samples to the liquid filling ring 12, the other end faces of the two rock samples will abut against each other (the sum of the axial lengths of the two rock samples is equal to the axial length of the liquid filling cylinder body 1), that is, the fracture spacing of the rock samples is zero at this time. If it is necessary to set the fracture spacing of the rock samples to 4 mm, when inserting the two rock samples from the large-diameter end of the connecting pipe 11 into the small-diameter end, make one end face of the rock sample exceed the small-diameter end face of the connecting pipe 11 by 2 mm. At this time, after bolting the two connecting pipes 11 holding the rock samples to the liquid filling ring 12, the distance between the other end faces of the two rock samples is 4 mm, that is, the fracture spacing of the rock samples is 4 mm at this time. The exposed dimensions of the two rock samples can be finely adjusted according to the experimental needs, so as to change the width of the water-containing fracture and realize the controllable loading of the fracture morphology.

[0034] 3. Connection and installation of the liquid filling cylinder body 1 and the height-adjustable support base 2: After completing the installation of the rock samples, position the limit block 122 corresponding to the position of the limit groove from top to bottom, place the liquid filling cylinder body 1 above the height-adjustable support base 2, and make the liquid filling port 13 face vertically upward. At this time, the small-diameter ends of the two connecting pipes 11 abut against the lower bolt seats 31 on both sides. By bolting the upper bolt cover 32 to the corresponding lower bolt seat 31, the relative fixation of the liquid filling cylinder body 1 and the support plate 22 is realized, and at the same time, a clamping force is applied to the small-diameter ends of the two connecting pipes 11 and the rock samples, that is, the connection and installation action of the liquid filling cylinder body 1 and the height-adjustable support base 2 is completed.

[0035] 4. Height adjustment and alignment of the liquid-filled cylinder 1: By rotating the rotating handle 29 in the forward direction, the trapezoidal lead screw 26 is driven to rotate forward, thereby driving the nut seat 27 to translate backward along the direction of the guide groove 213. The second sliding members 241 on both sides are driven by the connecting rod 28 to slide backward in the corresponding second sliding grooves 212, and simultaneously drive the first sliding member 231 to slide backward in the corresponding first sliding grooves 222, thereby driving the support plate 22 to rise vertically. By rotating the rotating handle 29 in the reverse direction, the trapezoidal lead screw 26 is driven to rotate in the reverse direction, thereby driving the nut seat 27 to translate forward along the direction of the guide groove 213. The second sliding members 241 on both sides are driven by the connecting rod 28 to slide forward in the corresponding second sliding grooves 212, and simultaneously drive the first sliding member 231 to slide forward in the corresponding first sliding grooves 222, thereby driving the support plate 22 to descend vertically. Repeat the above operations until the outer end faces of the two rock samples are in close contact with the incident bar and the transmission bar in the Hopkinson bar device respectively, and the two rock samples and the incident bar and the transmission bar are all in the coaxial position, that is, the installation and alignment action of the whole liquid filling device is completed.

[0036] 5. Construct a liquid-filled rock sample: Inject a predetermined volume of liquid (water or oil) into the liquid-filled cylinder 1 through the liquid filling port 13 on the liquid-filled cylinder 1 until the hydraulic sensor outputs an electrical signal indicating that the gap area between the two rock samples is completely filled with liquid, that is, the liquid filling action of the whole liquid filling device is completed.

[0037] 6. Dynamic experimental loading: Release the impact bar at a predetermined impact rate, drive the impact bar to impact the incident bar, thereby generating a stress wave (incident wave) that propagates along the incident bar to the specimen. When it propagates to the contact interface between the incident bar and the tested rock sample, due to the difference in wave impedance of the material medium, partial reflection will occur at this interface, forming a reflected stress wave that returns along the direction of the incident bar, and the signal is collected by the first strain gauge on the incident bar. At the same time, the remaining part of the stress wave passes through the interface and is transmitted into the interior of the tested rock sample. When the stress wave passes through the water-filled part, energy attenuation occurs. When the stress wave further propagates to the contact interface between the other end of the rock sample and the transmission bar, part of the energy continues to enter the transmission bar in the form of a transmitted wave and propagates forward along its axial direction, and the transmitted wave signal is then recorded in real time by the second strain gauge.

[0038] 7. Experimental monitoring and data acquisition: During the experimental loading process, obtain the dynamic changes of the liquid pressure in the cavity through the hydraulic sensor, and collect the dynamic response signals of the rock sample through the strain gauge.

[0039] 8. Data processing and analysis: The stress wave data, hydraulic change data, and crack evolution signals generated during the experiment are all recorded in real time by the data acquisition system in the Hopkinson bar device. After the acquisition is completed, the obtained data is preprocessed, fitted, and analyzed to obtain the dynamic relationship between the crack state, the action of the liquid, and the stress response, providing a reliable experimental basis for the dynamic response mechanism of liquid-containing fractured rock masses.

[0040] The incident strain signal collected by the first strain gauge , the reflected strain signal , and the transmitted strain signal collected by strain gauge 2 , and based on the one-dimensional stress wave propagation theory, the dynamic stress in the fluid-filled fracture impact test can be calculated according to the following equation , the dynamic strain and the dynamic compressive strain rate :

[0041]

[0042]

[0043] where is the elastic modulus of the rod, is the wave velocity of the stress wave propagating in the rod, is the length of the rock sample.

[0044] Although the present invention has been described by using the above preferred embodiments, it is not intended to limit the protection scope of the present invention. Any person skilled in the art can make various changes and modifications to the above embodiments without departing from the spirit and scope of the present invention, and still fall within the protection scope of the present invention.

Claims

1. A liquid filling device for Hopkinson bar experimental equipment, characterized in that, It includes a liquid-filled cylinder body (1) and a height-adjustable support base (2) for supporting the liquid-filled cylinder body (1). The liquid-filled cylinder body (1) includes a liquid-filled ring (12) provided with a liquid filling port (13). Connecting pipes (11) are respectively connected to both axial sides of the liquid-filled ring (12). The connecting pipes (11) are coaxial with the liquid-filled ring (12). The connecting pipes (11) are of a tapered structure. The large-diameter end of the connecting pipe (11) is detachably connected to the liquid-filled ring (12). The small-diameter end of the connecting pipe (11) is a clamping end for clamping one end of the rock sample. A support (14) for supporting the other end of the rock sample is provided inside the liquid-filled ring (12). A clamping connection assembly (3) for applying a clamping force to the outside of the small-diameter end of the connecting pipe (11) is provided. A hydraulic sensor is provided inside the liquid-filled ring (12).

2. The liquid filling device for Hopkinson bar experimental equipment according to claim 1, characterized in that, The height-adjustable support base (2) includes a base (21) and a support plate (22). A lifting assembly for driving the support plate (22) to lift and lower is provided on the base (21).

3. The liquid filling device for Hopkinson bar experimental equipment according to claim 2, characterized in that, The lifting assembly includes two scissor mechanisms correspondingly arranged below the small-diameter end of the connecting pipe (11). The scissor mechanism includes a lower connecting groove (211) arranged above the base (21), an upper connecting groove (221) arranged below the support plate (22), a first support rod (23), and a second support rod (24). One end of one side of the first support rod (23) is rotatably connected to one end of the lower connecting groove (211). A first sliding member (231) is rotatably connected to the other end of the first support rod (23). A first sliding groove (222) is correspondingly provided in the upper connecting groove (221). The first sliding member (231) is slidably connected to the first sliding groove (222). One end of one side of the second support rod (24) is rotatably connected to one end of the upper connecting groove (221). A second sliding member (241) is rotatably connected to the other end of the second support rod (24). A second sliding groove (212) is correspondingly provided in the lower connecting groove (211). The second sliding member (241) is slidably connected to the second sliding groove (212). The middle of the first support rod (23) is rotatably connected to the middle of the second support rod (24). The lifting assembly further includes a driving mechanism for driving the first sliding member (231) and the second sliding member (241) in the two scissor mechanisms to slide horizontally synchronously.

4. The liquid filling device for Hopkinson bar experimental equipment according to claim 3, characterized in that, The driving mechanism includes two fixed seats (25) arranged above the base (21). A trapezoidal lead screw (26) is rotatably connected to the fixed seat (25). A nut seat (27) is threadedly connected between the two fixed seats (25) on the trapezoidal lead screw (26). The nut seat (27) is horizontally connected with a connecting rod (28). The horizontal two ends of the connecting rod (28) are respectively connected to a second sliding member (241). A convex block (201) is provided below the nut seat (27). A guide groove (213) is correspondingly provided on the base (21). The convex block (201) is slidably connected in the guide groove (213). A rotating handle (29) is connected to the trapezoidal lead screw (26).

5. The liquid filling device for Hopkinson bar experimental equipment according to claim 1, characterized in that, The detachable connection structure between the large-diameter end of the connecting pipe (11) and the liquid filling ring (12) includes a flange plate (16). A first through hole (111) is provided corresponding to the large-diameter end of the connecting pipe (11), and a second through hole (121) is formed in the liquid filling ring (12). The connecting pipes (11) on both sides are bolted to the inner liquid filling ring (12) through the flange plate (16).

6. The liquid filling device for Hopkinson bar experimental equipment according to claim 1, characterized in that, A ball (15) is movably connected to the end of the bracket (14), and the ball (15) abuts against the rock sample.

7. The liquid filling device for Hopkinson bar experimental equipment according to claim 2, characterized in that, The clamping connection assembly (3) includes a lower bolt seat (31) arranged on the support plate (22), and an upper bolt cover (32) is bolted to the lower bolt seat (31) in the vertical direction.

8. The liquid filling device for Hopkinson bar experimental equipment according to claim 2, characterized in that, A limiting block (122) is provided at the bottom of the liquid filling ring (12), and a limiting groove is formed corresponding to the support plate (22).

9. The liquid filling device for Hopkinson bar experimental equipment according to claim 2, wherein A vertical rod (202) extends vertically from the base (21), and the support plate (22) is slidably connected to the vertical rod (202) in the vertical direction.

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