A liquid filling device for Hopkinson bar experimental equipment

Abstract

The present invention relates to the technical field of Hopkinson bar experiments, specifically a liquid filling device for Hopkinson bar experimental equipment, comprising a liquid filling cylinder and a height-adjustable support seat. The liquid filling cylinder includes a liquid filling ring with a liquid filling port. Connecting pipes are connected to both axial sides of the liquid filling ring. The connecting pipes are coaxial with the liquid filling ring and have a tapered, 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 clamps a rock sample. The liquid filling ring is internally provided with a bracket for supporting the rock sample. The small-diameter end of the connecting pipe is externally provided with a clamping connection assembly for applying a clamping force to the small-diameter end of the connecting pipe and connecting the liquid filling cylinder to the height-adjustable support seat. The liquid filling ring is internally provided with a hydraulic sensor. The present invention can stably, airtightly, and controllably fill the internal fractured region of a sample with liquid during high strain rate loading in a Hopkinson bar experiment, thereby enabling dynamic response research of water-containing fractured rock masses.

Description

Technical Field

[0001] The invention relates to the technical field of Hopkinson bar experiments, in particular to a liquid filling device for Hopkinson bar experimental equipment. Background Art

[0002] As an experimental method for testing the mechanical properties of materials under dynamic loads, the Hopkinson bar experimental setup primarily consists of a launch system, a rod system (impact rod, incident rod, transmission rod, and absorption rod), a data acquisition system (strain gauges, oscilloscope, and ultra-dynamic strain gauge), and a damping and absorption system. It is primarily used to measure the stress-strain relationship of a specimen under high strain rates. Traditional Hopkinson bar experimental systems are primarily used to study the dynamic properties of dry rock specimens. However, deep, fluid-filled rock fractures are ubiquitous in nature under long-term geological conditions. Water-filled fractures are unavoidable in geological structures in geotechnical engineering, underground tunneling, hydropower projects, and coalbed methane extraction. When subjected to high loads such as blasting and earthquakes, these fractures have a profound impact on the mechanical properties of the structure and severely compromise the stability of the engineering rock mass. Therefore, understanding the fundamental laws of stress wave propagation in water-filled fractured rock is crucial for predicting and assessing rock quality and engineering safety. With the advancement of related research, a feasible experimental setup is urgently needed to study the dynamic response of fluid-filled rock fractures under high strain rates.

[0003] Although extensive research has focused on the dynamic response of dry fractured rock, experimental approaches to studying the response mechanisms of fractures under saturated or fluid-filled conditions remain limited. Conventional experimental setups struggle to achieve in-situ fluid injection, sealing, and simultaneous loading control during dynamic loading of specimens under high strain rate loading. The lack of a controllable fluid injection device not only reduces experimental reproducibility but also limits in-depth investigation of the coupling effects of fracture seepage. Current studies on the propagation characteristics of stress waves in water-bearing fractures often utilize organic glass tubes and epoxy resin adhesive to create fluid-filled fracture specimens. Two rock specimens are connected through the organic glass tube (with an appropriate spacing between the samples for fluid filling). The rock specimen is then bonded to the organic glass tube with epoxy resin adhesive. Fluid is then injected through the injection holes in the organic glass tube to form the water-bearing fractured rock specimen.

[0004] However, the above method for preparing liquid-filled fracture specimens has the following defects: 1. The stiffness of the organic glass tube is lower than that of the rock sample. When the impact test is carried out using the Hopkinson bar device, the tube wall will crack or deform, seriously affecting the accuracy of the experimental data; 2. The epoxy resin is prone to cracks and bubbles during the curing process, causing the liquid in the tube to leak, thereby affecting the experimental results; 3. The epoxy resin glue will shift during the curing process, and it is impossible to ensure that the fracture spacing reaches the preset value, and the control accuracy is low; 4. The epoxy resin glue is used to form a permanent connection between the rock sample and the organic glass tube. It is difficult to disassemble and reuse after an experiment, resulting in large experimental losses and high costs. Summary of the Invention

[0005] The purpose of the present invention is to address the deficiencies in the prior art and provide a liquid filling device for a Hopkinson bar experimental device. The device can stably, airtightly, and controllably fill the internal fractured region of a specimen with liquid during a high strain rate loading experiment (such as a split-Hopkinson bar experiment) to study the dynamic response of water-containing fractured rock masses, thereby solving the problems existing in the above-mentioned prior art.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A liquid filling device for Hopkinson bar experimental equipment comprises a liquid filling cylinder and a height-adjustable support seat for supporting the liquid filling cylinder. The liquid filling cylinder comprises a liquid filling ring 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 and have a tapered 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 a rock sample. A bracket 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 small-diameter end of the connecting pipe is provided outside the small-diameter end of the connecting pipe. A hydraulic sensor is provided inside the liquid filling ring.

[0008] Furthermore, the height-adjustable support seat includes a base and a support plate, and the base is provided with a lifting component for driving the support plate to rise and fall.

[0009] The lifting assembly includes two scissor-type mechanisms correspondingly arranged below the small-diameter end of the connecting pipe, the scissor-type mechanisms including a lower connecting groove arranged above the base, an upper connecting groove arranged below the support plate, and a first support rod and a second support rod. One side 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 to the first sliding member corresponding to the first sliding groove opened in the upper connecting groove, the first sliding member is slidably connected to the first sliding member, one side 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 to the second sliding member, and the second sliding member is slidably connected to the second sliding member corresponding to the second sliding groove opened in the lower connecting groove. The second sliding member is slidably connected to the second sliding member, and the middle part of the first support rod is rotatably connected to the middle part of the second support rod. The lifting assembly also includes a driving mechanism for driving the first sliding member and the second sliding member in the two scissor-type mechanisms to slide horizontally synchronously.

[0010] Furthermore, the driving mechanism includes two fixed seats arranged above the base, and a trapezoidal screw is rotatably connected to the fixed seat, and a nut seat is threadedly connected to the trapezoidal screw between the two fixed seats, and the nut seat is connected to a connecting rod in the horizontal direction, and the horizontal ends of the connecting rod are respectively connected to a second sliding member, and a protrusion is provided under the nut seat, and a corresponding guide groove is opened on the base, the protrusion is slidably connected in the guide groove, and a rotating handle is connected to the trapezoidal screw.

[0011] 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 provided on the large-diameter end of the connecting pipe, and a second through hole is provided on the liquid filling ring. The connecting pipes on both sides are bolted to the inner liquid filling ring through the flange.

[0012] Furthermore, a ball is movably connected to the end of the bracket, and the ball abuts against the rock sample.

[0013] Furthermore, the clamping connection assembly includes a lower bolt seat arranged on the support plate, and the lower bolt seat is bolted to an upper bolt cover in the vertical direction.

[0014] Furthermore, a limiting block is provided at the bottom of the liquid-filled ring, and a corresponding limiting groove is provided on the support plate.

[0015] Furthermore, the base is provided with a vertical rod extending in the vertical direction, and the support plate is slidably connected to the vertical rod in the vertical direction.

[0016] Compared with the existing technology, the liquid filling device proposed in this invention, which is used in conjunction with the Hopkinson bar experimental device, addresses the core technical difficulty of implementing dynamic response testing of fractured rock masses in a liquid-containing state in a split Hopkinson bar (SHPB) system. This provides a technical solution with a compact structure, simple operation, and strong repeatability, and has the following beneficial effects and application value:

[0017] 1. Improved sealing performance: The present invention uses high-strength bolts to fasten the connection between the liquid-filled ring, the connecting pipe and the flange to construct a closed liquid-filled cavity, which can 2 s -1 to 10 4 s -1 The overall structure of the device is kept stable under high strain rate impact, effectively preventing liquid leakage. Compared with the traditional one-time sealing method that relies on organic glass tubes and epoxy resin bonding, it has higher sealing, repeatability and structural toughness.

[0018] 2. Dynamic fluid-filled fracture construction capability: By clamping the rock sample on the small-diameter end of the connecting tube, the device can quickly construct fluid-filled fractures. The fracture width can be adjusted from 0 to 10 mm, supporting the simulation of water-rock coupling states at different scales. Users can quickly and arbitrarily adjust according to experimental needs.

[0019] 3. Support for multi-physics field synchronous testing: The device integrates hydraulic sensors and the mechanical acquisition module of the Hopkinson bar device, which can synchronously obtain the fracture pressure evolution curve and dynamic stress-strain response curve to meet the needs of multi-parameter correlation analysis.

[0020] 4. Realistic mechanical simulation: The present invention designs four brackets with ball bearings inside the liquid-filled ring to support the rock sample and allow it to generate free micro-displacement in the loading direction, thereby reducing the interference of diffuse waves caused by clamping, more realistically reflecting the stress and deformation behavior of the rock sample in the natural environment, and improving the geological restoration of the test simulation.

[0021] 5. Size adaptability and height adjustment capability: The height-adjustable support base in the present invention is not only equipped with a clamping and connecting component for clamping and connecting functions, but also can adjust the height of the support plate through a lifting component, so that the rock sample, the impact rod and the incident rod are tightly fitted and in a coaxial position, greatly improving the versatility and modular adaptability of the experimental device.

[0022] 6. Disassembled structure, economical and environmentally friendly: The present invention adopts a split and detachable design, and each component can be replaced, disassembled and cleaned independently. Compared with the one-time packaging means such as epoxy resin glue used in traditional test methods, the present invention has a reusable structure, which not only reduces sample loss and material waste, but also greatly improves experimental efficiency and resource utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of the overall structure of a liquid filling device for a Hopkinson bar experimental device provided by the present invention;

[0024] Figure 2 A right side view of a liquid filling device for a Hopkinson bar experimental device provided by the present invention;

[0025] Figure 3 A schematic diagram of the overall structure of a liquid-filled cylinder in a liquid-filled device for a Hopkinson bar experimental device provided by the present invention;

[0026] Figure 4 An exploded view of a liquid-filled cylinder in a liquid-filled device for a Hopkinson bar experimental device provided by the present invention;

[0027] Figure 5 A schematic structural diagram of a liquid filling ring in a liquid filling device for a Hopkinson bar experimental device provided by the present invention;

[0028] Figure 6 A schematic structural diagram of a lifting assembly in a liquid filling device for a Hopkinson bar experimental device provided by the present invention;

[0029] Figure 7 The present invention provides a schematic structural diagram of a nut seat in a liquid filling device for Hopkinson bar experimental equipment.

[0030] Wherein, the accompanying drawings are marked as follows:

[0031] 1. Liquid filling cylinder; 11. Connecting pipe; 111. First through hole; 12. Liquid filling ring; 121. Second through hole; 122. Stop block; 13. Liquid filling port; 14. Bracket; 15. Ball bearing; 16. Flange;

[0032] 2. Height-adjustable support base; 21. Base; 211. Lower connecting groove; 212. Second slide groove; 213. Guide groove; 22. Support plate; 221. Upper connecting groove; 222. First slide groove; 23. First support rod; 231. First sliding member; 24. Second support rod; 241. Second sliding member; 25. Fixed base; 26. Trapezoidal screw; 27. Nut seat; 28. Connecting rod; 29. Turning handle; 201. Bump; 202. Vertical rod;

[0033] 3. Clamping connection assembly; 31. Lower bolt seat; 32. Upper bolt cover. DETAILED DESCRIPTION

[0034] In order to help those skilled in the art better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0035] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may 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 may be directly connected to the other element or indirectly connected to the other element.

[0036] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or to implicitly indicate the quantity of the technical features indicated. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features.

[0038] For easier understanding, see Figures 1 to 5This embodiment provides a liquid filling device for a Hopkinson bar experimental apparatus. The device comprises a liquid filling cylinder 1 and a height-adjustable support base 2 positioned below the liquid filling cylinder 1. The height-adjustable support base 2 supports the liquid filling cylinder 1. The liquid filling cylinder 1 includes two connecting tubes 11 and a liquid filling ring 12 positioned between the two connecting tubes 11. Both connecting tubes 11 are horizontally coaxial with the liquid filling ring 12. The liquid filling ring 12 defines a liquid filling port 13 through which liquid (water or oil) is injected into the liquid filling cylinder 1. The connecting tube 11 has a tapered structure. Its large-diameter end is bolted to the liquid filling ring 12, while its small-diameter end serves as a clamping end for holding the horizontal end of a rock sample. Four brackets 14 are positioned within the liquid filling ring 12 to support the other end of the rock sample. One end of the rock sample is clamped by the connecting tube 11, while the other end extends into the liquid filling ring 12 and abuts against two of the brackets 14, ensuring that the rock sample remains horizontal after installation. The ends of the brackets 14 are movably connected to balls 15, which abut against the rock sample. The balls 15 reduce the friction between the rock sample and the bracket 14, thereby reducing the interference of the dispersed waves caused by clamping, reflecting the behavior of the rock sample under stress 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. Correspondingly, a plurality of horizontal first through holes 111 are opened on the large-diameter end of the connecting pipe 11, and a plurality of horizontal second through holes 121 are opened on the liquid filling ring 12. A plurality of long bolts are sequentially passed through the left flange 16, the first through hole 111 at the large-diameter end of the left connecting pipe 11, the second through hole 121 of the liquid filling ring 12, the first through hole 111 at the large-diameter end of the right connecting pipe 11, and the right flange 16, thereby achieving relative fixation of the connecting pipes 11 and the liquid filling ring 12 on both sides. A clamping connection assembly 3 is provided on the outside of the small-diameter end of the connecting tube 11. The clamping connection assembly 3 can connect the liquid-filled cylinder 1 and the height-adjustable support seat 2 to each other to achieve relative fixation between the two. At the same time, it can also apply a clamping force to the small-diameter end of the connecting tube 11, and then apply a clamping force to the rock sample through the small-diameter end of the connecting tube 11, ensuring that the two rock samples are stably clamped at the small-diameter ends of the connecting tubes 11 on both sides, forming a closed liquid-filled space inside the liquid-filled cylinder 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 set on the height-adjustable support seat 2. The inner wall of the lower bolt seat 31 abuts the outer wall of the small-diameter end of the connecting tube 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-filled ring 12. The hydraulic sensor is used to record the pressure signal generated by the liquid inside the liquid-filled cylinder 1 on the rock sample in real time.Preferably, the liquid filling ring 12 and the two flanges 16 are made of high-strength titanium alloy steel, and the connecting pipe 11 is made of a steel 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 from the large-diameter end of the connecting pipe 11 into the small-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 enclosed 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 to prevent water seepage for the small-diameter end of the connecting pipe 11, structural deformation at the small-diameter end of the connecting pipe 11 due to excessive clamping force is avoided.

[0039] The staff horizontally clamped and installed the two rock samples on the small-diameter ends of the connecting tubes 11 on both sides, and fixed the connecting tubes 11 on both sides to the liquid filling ring 12 through bolt connection, forming a closed cavity inside the liquid filling cylinder 1. Then, the outer end faces of the two rock samples were closely contacted with the incident rod and the transmission rod in the Hopkinson bar experimental device to ensure the effective transmission of force between the rock samples and the incident rod and the transmission rod. After that, a predetermined volume of liquid (water or oil) was injected into the sealed cavity through the liquid filling port 13 on the liquid filling ring 12, so that the liquid completely filled the gap area between the two rock samples, thereby simulating the rock sample structure with controllable water-containing fractures.

[0040] For easier understanding, please refer to Figures 1 to 6The height-adjustable support base 2 includes a base 21 and a support plate 22 located above the base 21. The base 21 is provided with a lifting assembly for driving the support plate 22 to vertically rise and fall. 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 connecting tubes 11 on both sides. Specifically, the scissor mechanisms include a lower connecting groove 211 fixed horizontally and longitudinally above the base 21, an upper connecting groove 221 fixed horizontally and longitudinally below the height-adjustable support base 2, a first support rod 23, and a second support rod 24. The front end of the upper connecting groove 221 is provided with a first horizontal and transverse sliding groove 222, and the front end of the lower connecting groove 211 is provided with a second horizontal and transverse sliding groove 212. The rear end of the first support rod 23 is rotatably connected to the rear end of the lower connecting groove 211, and the front end of the first support rod 23 is rotatably connected to the first sliding member 231. 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 the second sliding member 241. The second sliding member 241 is slidably connected in the second sliding groove 212. The middle portion of the first support rod 23 is rotatably connected to the middle portion of the second support rod 24. The staff drives the second sliding members 241 in the two scissor mechanisms through the driving mechanism to slide horizontally and longitudinally in the corresponding second sliding groove 212, respectively, driving the corresponding first sliding members 231 to slide horizontally and longitudinally in the first sliding groove 222 synchronously, thereby driving the support plate 22 to rise and fall vertically. Specifically, when the drive mechanism drives the second slides 241 of the two scissor-type mechanisms to slide from front to back within the second chute 212, the support plate 22 rises vertically. When the drive mechanism drives the second slides 241 of the two scissor-type mechanisms to slide from back to front within the second chute 212, the support plate 22 descends vertically. In the initial state (i.e., the distance between the support plate 22 and the base 21 is minimal), the two first slides 231 are both located at the front end of the first chute 222, the two second slides 241 are both located at the front end of the second chute 212, and the two lower bolt seats 31 are horizontally coaxial.

[0041] For easier understanding, please refer to Figures 1 to 7The drive mechanism includes two fixed seats 25 fixed to the base 21 at intervals in the horizontal longitudinal direction. A trapezoidal lead screw 26 extends horizontally and longitudinally through the two fixed seats 25 and is rotatably connected to the fixed seats 25. A nut seat 27 is disposed between the two fixed seats 25 and is threadedly connected to the trapezoidal lead screw 26. A protrusion 201 is fixed below the nut seat 27, corresponding to a horizontal longitudinal guide groove 213 provided on the base 21. The protrusion 201 is slidably connected within the guide groove 213. Connecting rods 28 are fixedly extended outward from the nut seat 27 on both horizontal sides. The two connecting rods 28 are respectively fixedly connected to the second sliding members 241 on both sides. A rotating handle 29 is fixedly connected to the front end of the trapezoidal lead screw 26. The lead angle of the thread of the trapezoidal lead screw 26 is less than the static friction angle, so that the friction between the trapezoidal lead screw 26 and the nut seat 27 is sufficient to prevent reverse motion, that is, it can achieve self-locking. The staff turns the handle 29 to drive the trapezoidal screw 26 to rotate, and then drives the nut seat 27 to translate along the guide groove 213, and finally drives the second sliding member 241 to slide horizontally and longitudinally in the second slide groove 212 through the translation of the connecting rod 28 fixed on both sides of the nut seat 27. When the lifting and lowering action of the support plate 22 is completed, the trapezoidal screw 26 can self-lock in position to avoid the reverse movement of the trapezoidal screw 26 and the nut seat 27 due to the dead weight of the liquid-filled cylinder 1 and the scissors-type mechanism, thereby preventing the support plate 22 from automatically falling and causing the lifting component to fail.

[0042] For easier understanding, please refer to Figures 1 to 7 The base 21 is provided with eight vertical rods 202 extending in the vertical direction, which are respectively located around the two scissor-type 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 scissor-type mechanisms on both sides, thereby ensuring that the support plate 22 always remains in a horizontal state before and after lifting. A limit block 122 is provided at the bottom of the liquid filling ring 12, and a limit groove is provided in the middle of the support plate 22. The position of the limit block 122 corresponds to the position of the limit groove, which facilitates the installation and alignment of the liquid filling cylinder 1 by the staff. By simply placing the limit block 122 below the liquid filling cylinder 1 in the position corresponding to the limit groove, the small-diameter ends of the connecting pipes 11 on both sides 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.

[0043] The method of using the present invention:

[0044] 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 the connecting pipe 11, lifting assembly, flange 16 and liquid filling ring 12 of the liquid filling device, to ensure that the surface of the above components is free of cracks, aging, leakage or other defects that affect the experimental performance, and are in normal working condition.

[0045] 2. Rock sample installation and crack spacing adjustment: The axial length of the liquid filling ring 12 is 20mm, and the axial length of the two connecting tubes 11 is 40mm. That is, after the liquid filling ring 12 and the two connecting tubes 11 are installed, the axial length of the liquid filling cylinder 1 is 100mm. Take two rock samples with an axial length of 50mm to be tested, and insert the two rock samples from the large-diameter end of the connecting tube 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 tube 11. At this time, after the two connecting tubes 11 holding the rock samples are bolted to the liquid filling ring 12, the other end faces of the two rock samples will abut each other (the axial length of the two rock samples is 50mm). The sum of the lengths is equal to the axial length of the liquid-filled cylinder 1), that is, the crack spacing of the rock sample is zero at this time; if the crack spacing of the rock sample needs to be set to 4 mm, then when the two rock samples are respectively inserted from the large-diameter end to the small-diameter end of the connecting tube 11, the end face of one side of the rock sample is made to extend 2 mm beyond the small-diameter end face of the connecting tube 11. At this time, after the two connecting tubes 11 holding the rock samples are bolted to the liquid-filled ring 12, the spacing between the end faces of the other side of the two rock samples is 4 mm, that is, the crack spacing of the rock sample is 4 mm at this time; the exposed size of the two rock samples can be fine-tuned according to experimental needs, thereby changing the width of the water-bearing cracks and realizing controllable loading of the crack morphology.

[0046] 3. Connection and installation of the liquid-filling cylinder 1 and the height-adjustable support seat 2: After completing the installation of the rock sample, move the limit block 122 from top to bottom to the position of the corresponding limit groove, place the liquid-filling cylinder 1 above the height-adjustable support seat 2, and make the liquid filling port 13 face vertically upward. At this time, the small-diameter ends of the connecting pipes 11 on both sides abut against the lower bolt seats 31 on both sides, and are bolted to the corresponding lower bolt seats 31 through the upper bolt cover 32, so that the liquid-filling cylinder 1 and the support plate 22 are relatively fixed, and at the same time, a clamping force is applied to the small-diameter connecting pipes 11 on both sides and the rock sample, thus completing the connection and installation of the liquid-filling cylinder 1 and the height-adjustable support seat 2.

[0047] 4. Height adjustment and alignment of the liquid-filled cylinder 1: By rotating the handle 29 in the forward direction, the trapezoidal screw 26 is driven to rotate in the forward direction, thereby driving the nut seat 27 to translate backward along the guide groove 213, and the second sliding members 241 on both sides are driven to slide backward in the corresponding second sliding groove 212 through the connecting rod 28, and the first sliding member 231 is simultaneously driven to slide backward in the corresponding first sliding groove 222, thereby driving the support plate 22 to rise vertically; by rotating the handle 29 in the reverse direction, the trapezoidal screw 26 is driven to rotate in the reverse direction, thereby driving the nut The seat 27 translates forward along the guide groove 213, and drives the second sliding members 241 on both sides to slide forward in the corresponding second sliding grooves 212 through the connecting rod 28, and simultaneously drives the first sliding member 231 to slide forward in the corresponding first sliding groove 222, thereby driving the support plate 22 to descend vertically; repeat the above operation until the outer end faces of the left and right rock samples are respectively in close contact with the incident rod and the transmission rod in the Hopkinson bar device, and the two rock samples are in a coaxial position with the incident rod and the transmission rod, that is, the installation and alignment action of the entire liquid filling device is completed.

[0048] 5. Constructing a liquid-filled rock sample: A predetermined volume of liquid (water or oil) is injected into the liquid-filled cylinder 1 through the liquid-filling port 13 on the liquid-filling cylinder 1 until the hydraulic sensor outputs an electrical signal indicating that the liquid completely fills the gap between the two rock samples, thus completing the filling operation of the entire liquid-filling device.

[0049] 6. Dynamic experimental loading: The impact rod is released at a predetermined impact rate, driving the impact rod to hit the incident rod, thereby generating a stress wave (incident wave) that propagates along the incident rod to the sample. When propagating to the contact interface between the incident rod and the rock sample, due to the difference in wave impedance of the material medium, the interface will produce partial reflection, forming a reflected stress wave, which returns along the direction of the incident rod. The signal is collected by the first strain gauge on the incident rod; at the same time, the remaining stress wave passes through the interface and is transmitted to the interior of the rock sample. When the stress wave passes through the water-filled part, the energy of the stress wave is attenuated; when the stress wave further propagates to the contact interface between the other end of the rock sample and the transmission rod, part of the energy continues to enter the transmission rod in the form of a transmitted wave and propagates forward along its axial direction. The transmitted wave signal is then recorded in real time by the second strain gauge.

[0050] 7. Experimental monitoring and data acquisition: During the experimental loading process, the dynamic changes of the liquid pressure in the cavity are obtained through the hydraulic sensor, and the dynamic response signal of the rock sample is collected through the strain gauge.

[0051] 8. Data Processing and Analysis: The stress wave data, hydraulic change data, and fracture evolution signals generated during the experiment are all recorded in real time by the data acquisition system in the Hopkinson bar device. After acquisition, the obtained data are preprocessed, fitted, and analyzed to obtain the dynamic relationship between fracture state, liquid action, and stress response, providing a reliable experimental basis for the dynamic response mechanism of fluid-containing fractured rock masses.

[0052] Incident strain signal collected by the first strain gauge , reflected strain signal , and the transmission strain signal collected by strain gauge 2 , and based on the one-dimensional stress wave propagation theory, the dynamic stress in the fluid-filled crack impact test can be calculated according to the following equation: , dynamic strain and dynamic compressive strain rate :

[0053]

[0054]

[0055]

[0056] in is the elastic modulus of the rod, is the wave velocity of stress wave propagating in the rod, is the length of the rock sample.

[0057] Although the present invention has been described using the above preferred embodiments, they are not intended to limit the scope of protection of the present invention. Any person skilled in the art who makes various changes and modifications to the above embodiments without departing from the spirit and scope of the present invention still fall within the scope of protection of the present invention.

Claims

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

2. The liquid filling device for the Hopkinson bar experimental equipment according to claim 1, characterized in that: The height-adjustable support seat (2) comprises a base (21) and a support plate (22); the base (21) is provided with a lifting assembly for driving the support plate (22) to move up and down.

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

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

5. The liquid filling device for the 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) comprises a flange (16), a first through hole (111) is correspondingly provided on the large-diameter end of the connecting pipe (11), and a second through hole (121) is opened on the liquid-filling ring (12), and the connecting pipes (11) on both sides are bolted to the inner liquid-filling ring (12) through the flange (16).

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

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

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

9. The liquid filling device for the Hopkinson bar experimental equipment according to claim 2, characterized in that: The base (21) is provided with a vertical rod (202) extending in the vertical direction, and the support plate (22) is slidably connected to the vertical rod (202) in the vertical direction.

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