An underground engineering high stress surrounding rock and supporting structure rheological simulation experiment device

Abstract

The present application relates to geotechnical engineering test technical field, more specifically, relate to a kind of underground engineering high stress surrounding rock and supporting structure rheological simulation experiment device, including box, surrounding rock simulation material is placed in box, supporting assembly is inserted in surrounding rock simulation material, the upper end of surrounding rock simulation material is equipped with multiple pressing plate, multiple displacement side holes are opened in the side surface of box, pressure applying assembly is installed in the side surface of box, the lower end of pressure applying assembly is on multiple pressing plate, pressure applying assembly can apply different pressure to multiple pressing plate, the accurate reconstruction of non-uniform stress gradient on the surface of surrounding rock model is realized based on the coordinated design of multiple pressing plate independent pressure applying assembly and telescopic lever mechanism, the problem that stress field is distorted due to the fact that traditional device can only apply uniform load is solved, and the engineering fidelity of rheological experiment and load adjustment safety are improved.

Description

Technical Field

[0001] This invention relates to the field of geotechnical engineering testing technology, and more specifically, to a rheological simulation experimental device for high-stress surrounding rock and support structures in underground engineering. Background Technology

[0002] Compared to shallow underground engineering, the behavior of high-stress surrounding rock in deep underground engineering excavation rapidly exhibits complex unsteady and nonlinear characteristics. Significant rheological changes occur in the surrounding rock after the plastic zone deteriorates in deep underground engineering. Field observations show that the failure depth of the surrounding rock in the tunnel exceeds the support range of the anchoring system, and the tunnel walls exhibit overall extrusion rheology of the anchor body (support system), i.e., structural rheology of the anchor body. The large deformation in underground engineering has evolved from traditional soft rock rheology to large deformation involving both soft rock rheology and structural rheology of the anchor body.

[0003] In underground engineering research, physical model testing is an important means to reveal the rheological mechanism of high-stress surrounding rock and verify the effectiveness of support structures. For example, Chinese patent application number 202011326140.X discloses a soft rock rheological testing device and method. It uses a lever force transmission device, a loading device, and a measuring device to form a lever loading test structure. The lever frame, loading lever, and force-applying lever form a stable lever loading structure. The test piece is placed using the loading device. The lever structure formed by the lever force transmission device amplifies the gravity load on the test piece to form a stable gravity load test structure. At the same time, the measuring device collects circumferential and axial pressure deformation data of the test piece. However, the above scheme can only be used to analyze the rheological properties of the rock mass itself and cannot be used to specifically explore the rheological properties and mechanisms of high-stress surrounding rock and support structures in deep underground engineering.

[0004] Existing rheological simulation experimental devices typically employ monolithic rigid loading or simple lever-weight loading methods. However, deep surrounding rock in actual engineering projects exists in a complex high-stress environment, and the stress distribution often exhibits non-uniform gradient characteristics. Existing devices struggle to apply differentiated zoned pressures to the surrounding rock model, resulting in an inability to realistically simulate the evolution of stress gradients within the surrounding rock. Furthermore, traditional devices rely heavily on manually adding or removing solid weights to maintain or adjust the load during long-term rheological tests. This is not only cumbersome and labor-intensive, but also prone to safety hazards such as counterweight instability and fall during high-frequency adjustments. Additionally, the discreteness of solid weights limits the accuracy and continuity of load adjustment, making it difficult to meet the requirements of high-precision rheological tests under different stress environments and stress paths. Summary of the Invention

[0005] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. The summary section of this invention is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0006] To at least partially solve the above problems, the present invention provides an experimental device for simulating the rheological properties of high-stress surrounding rock and support structures in underground engineering, comprising a box, a surrounding rock simulation material placed inside the box, a support component inserted inside the surrounding rock simulation material, multiple pressure plates at the upper end of the surrounding rock simulation material, multiple displacement side holes opened on the side of the box, a pressure application component installed on the side of the box, the lower end of the pressure application component abutting against the multiple pressure plates, and the pressure application component can apply different pressures to the multiple pressure plates.

[0007] Furthermore, the housing includes a base plate with two vertically arranged side plates on the base plate. The bottom of both side plates is fixed to the base plate by a locking structure, and the upper ends of the two side plates are fixed together by a tie rod. One of the side plates has multiple displacement side holes. A water tank is provided on the base plate. The water tank is fixedly connected to an industrial camera through a first bracket. The lens of the industrial camera is aimed at the displacement side holes, and digital speckle technology is used to monitor the horizontal and vertical displacement of the surrounding rock simulation material in the displacement side holes.

[0008] Furthermore, the locking structure includes a support screw, which is fixed to the base plate and slides in a long groove on the side plate. Both sides of the long groove are fixed with lower positioning plates by locking screws. The lower positioning plate is provided with a first protrusion. The support screw is threadedly connected to a tightening nut. The lower end of the tightening nut is inserted into the upper end of the upper positioning plate. The upper positioning plate is sleeved on the outside of the support screw. The lower end of the upper positioning plate is provided with a second protrusion, and the first protrusion meshes with the second protrusion.

[0009] Furthermore, an end plate is fixed to the end of the base plate, and both side plates are fixed to the end plate by bolts. The surrounding rock simulation material is placed between the two side plates, with one end of the surrounding rock simulation material abutting against the end plate and the other end of the surrounding rock simulation material being inserted into a support component.

[0010] Furthermore, the support assembly includes an anchor bolt, the front end of which is inserted into the surrounding rock simulation material, an anchoring agent is provided between the anchor bolt and the surrounding rock simulation material, a nut is threadedly connected to the tail end of the anchor bolt, a tray is fitted on the anchor bolt, the tray is located between the nut and the end face of the surrounding rock simulation material, and the side plate is fixedly connected to the second tie rod displacement gauge through the second bracket, and the measuring end of the second tie rod displacement gauge is connected to the tail end of the anchor bolt.

[0011] Furthermore, the pressure application assembly includes a support, the lower end of which is fixed to a base plate, and a plurality of supporting outer arms are rotatably connected to the upper end of the support. A plurality of pressure rod sleeves are respectively fixed to the lower ends of the plurality of supporting outer arms, and a plurality of pressure rods are respectively threaded to the lower ends of the plurality of pressure rods. The lower ends of the plurality of pressure rods abut against a plurality of pressure plates and apply different pressures to the plurality of pressure plates. The support is fixedly connected to a third tie rod displacement gauge through a third bracket, and the measuring end of the third tie rod displacement gauge is connected to the upper end of the pressure plate.

[0012] Furthermore, an inner support arm is slidably connected to the outer support arm, and a toothed protrusion is provided at the lower end of the inner support arm. A toothed plate is slidably connected to the outer support arm. The outer support arm is threadedly connected to a locking screw. The upper end of the locking screw presses the toothed plate to move upward within the outer support arm, and a toothed protrusion is provided on the toothed plate to mesh with the toothed protrusion.

[0013] Furthermore, a support ring is snapped onto the front end of the inner support arm, and a support cap is fixed to the lower end of the support ring. The support cap is connected to the counterweight barrel through a gravity self-locking assembly. Two adjacent counterweight barrels are connected through a gravity self-locking assembly. The upper end of the counterweight barrel is provided with a water inlet, and the lower end of the counterweight barrel is provided with a water outlet. Both the water inlet and the water outlet are provided with stopcocks. The water tank can inject water into the counterweight barrel through the water inlet, and the counterweight barrel can discharge water into the water tank through the water outlet.

[0014] Furthermore, the gravity self-locking assembly includes an outer slip ring, which slides on the outside of the counterweight barrel port. Both sides of the outer slip ring are provided with outer protrusions. A spring is provided between the outer slip ring and the counterweight barrel. An inner slip ring is slidably connected to the upper end of the counterweight barrel. A sealing ring is provided at the upper end of the inner slip ring. The lower end of the inner slip ring is fixedly connected to the outer slip ring through multiple support rods. All the support rods slide inside the counterweight barrel.

[0015] Furthermore, both sides of the counterweight barrel are provided with locking blocks, and both locking blocks slide on the bottom of the outer slip ring. The lower end of both locking blocks is provided with protruding teeth. The lower end of the support cap is open, and the edge of the opening is provided with two inner bosses. One end of the inner boss is set with an inclined surface, and the other end of the inner boss is provided with a baffle. The inner boss is provided with a tooth groove. The upper end of the counterweight barrel is inserted into the support cap, and the sealing ring abuts against the top of the support cap. When the counterweight barrel is rotated, the two outer bosses are respectively locked onto the two inner bosses. After water is filled into the counterweight barrel, the counterweight barrel moves down, and the protruding teeth and tooth grooves engage and lock.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: This application provides a simulation experimental device for the structural rheology of high-stress surrounding rock and support structures, which solves the problem that traditional soft rock rheology devices cannot be used to explore the structural rheological characteristics and mechanisms. Specific effects include: 1. By combining the multi-plate independent pressure application components with the telescopic lever mechanism, the non-uniform stress gradient on the surface of the surrounding rock model is accurately reconstructed based on the principle of partitioned loading. This solves the problem that traditional devices can only apply uniform loads, which leads to stress field distortion and significantly improves the engineering realism of rheological simulation experiments.

[0017] 2. By adopting a water-medium counterweight combined with a gravity self-locking component, and utilizing the principles of hydrostatics and a mechanical gravity induction triggering mechanism, stepless continuous adjustment of the load and automatic anti-disengagement locking under heavy load conditions are achieved. This overcomes the shortcomings of solid weight loading, such as large dispersion, cumbersome adjustment, and high safety hazards. Under the premise of ensuring experimental safety, the load control accuracy and experimental efficiency are greatly improved.

[0018] 3. The toothed locking structure of the box side plate and the complete support simulation components together construct a high-rigidity, true-boundary experimental environment, providing reliable hardware support for in-depth research on the rheological coupling mechanism of deep high-stress surrounding rock-support system.

[0019] 4. By using contact displacement gauges and non-contact digital speckle technology, the overall displacement of the anchor bolt, the overall vertical displacement of the surrounding rock, and the horizontal and vertical displacements of the support structure at different locations can be monitored and acquired simultaneously during the experiment, which facilitates the investigation of structural rheological characteristics.

[0020] 5. During the experiment, the pressure gradient can be adjusted to simulate different stress environments, and the ratio of surrounding rock simulation materials can be adjusted to simulate rocks with different strengths and porosities, which facilitates the exploration of the structural rheological mechanism of different surrounding rocks and supports under different stress environments and stress paths.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the box structure of the present invention; Figure 3 for Figure 2 Enlarged view of a portion of point A in the middle; Figure 4 This is a schematic diagram of the support component structure of the present invention. Figure 1 ; Figure 5 This is a schematic diagram of the support component structure of the present invention. Figure 2 ; Figure 6 for Figure 5 Enlarged view of a section at point B in the middle; Figure 7 This is a schematic diagram of the pressure application component structure of the present invention. Figure 1; Figure 8 This is a schematic diagram of the pressure application component structure of the present invention. Figure 2 ; Figure 9 for Figure 8 Enlarged view of a section at point C; Figure 10 for Figure 8 Enlarged view of a section at point D; Figure 11 This is a schematic diagram of the counterweight barrel structure of the present invention. Figure 1 ; Figure 12 This is a schematic diagram of the counterweight barrel structure of the present invention. Figure 2 ; Figure 13 for Figure 12 Enlarged view of a section at point E in the middle; Figure 14 This is a schematic diagram of the sealing ring structure of the present invention; Figure 15 This is a schematic diagram of the support cap structure of the present invention; Explanation of markings in the diagram: 1. Base plate; 2. Side plate; 3. Support screw; 4. Long groove; 5. Lower positioning plate; 6. Locking screw; 7. Upper positioning plate; 8. Tightening nut; 9. Displacement side hole; 10. Pressure plate; 11. End plate; 12. Tie rod; 13. Surrounding rock simulation material; 14. Anchor bolt; 15. Anchoring agent; 16. Tray; 17. Nut; 18. Support outer arm; 19. Pressure rod sleeve; 20. Pressure rod; 21. Support inner arm; 22. Toothed plate; 23. Locking screw II; 24. Support ring; 25. Support cap; 26. Inner boss; 27. Toothed groove; 28. Baffle; 29. ​​Counterweight barrel; 30. Outer slip ring; 31. Outer boss; 32. Clamping block; 33. Convex tooth; 34. Spring; 35. Sealing ring; 36. Inner slip ring; 37. Support rod; 38. Water tank; 39. Industrial camera; 40a. Second tie rod displacement gauge; 40b. Third tie rod displacement gauge; 40c. Detailed Implementation

[0023] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0025] Example 1: As Figures 1-15 As shown, an experimental device for simulating the rheological properties of high-stress surrounding rock and support structure in underground engineering includes a box, in which a surrounding rock simulation material 13 is placed, and a support component is inserted into the surrounding rock simulation material 13. Multiple pressure plates 10 are provided on the upper end of the surrounding rock simulation material 13, and multiple displacement side holes 9 are opened on the side of the box. A pressure application component is installed on the side of the box, and the lower end of the pressure application component abuts against the multiple pressure plates 10. The pressure application component can apply different pressures to the multiple pressure plates 10. The working principle of the above technical solution is as follows: The box body serves as the basic load-bearing and boundary constraint container for the entire simulation experiment. It is usually assembled from high-strength metal plates. The closed or semi-closed cavity formed inside is used to contain the surrounding rock simulation material 13. The surrounding rock simulation material 13 can be gypsum or cement mortar mixed according to similarity theory to simulate the mechanical behavior of specific rock types in deep underground engineering. The design of the box body not only provides physical storage space, but also provides the necessary lateral and bottom boundary conditions for the surrounding rock model through its own stiffness, ensuring the stability of the stress transmission path during the experiment. The support components are pre-embedded or implanted into the surrounding rock simulation material 13 according to preset spacing parameters to reproduce the interaction between active support structures such as anchor bolts and anchor cables and the surrounding rock in actual engineering. Unlike traditional integral loading cover plates, multiple pressure plates 10 are arranged in zones along the upper surface of the surrounding rock simulation material 13. For example, they can be divided into several independent rectangular or strip-shaped pressure-bearing units along the axial or radial direction of the roadway. This zoned arrangement discretizes the originally continuous surrounding rock roof into multiple independently load-bearing areas, providing a physical interface for the subsequent construction of a non-uniform stress field. It should be understood that the number, shape, and arrangement of the pressure plates 10 can be adjusted according to the needs of the simulation conditions, as long as the zoned load-bearing function can be achieved. The displacement side hole 9 penetrates the side wall of the box, providing a non-destructive access channel for external monitoring equipment. This allows researchers to simultaneously collect deformation data from the deep and surface of the surrounding rock, and then analyze the damage evolution law during the rheological process. The pressure application component is installed on the side or top side of the box, and its power output end forms an independent mechanical transmission link with the multiple pressure plates 10 above. By adjusting the magnitude of the force applied by the pressure application component to each pressure plate 10, a stress gradient distribution that conforms to engineering reality can be reconstructed on the surface of the surrounding rock simulation material 13. For example, it can simulate the coexistence of stress concentration area and decompression area under the influence of mining. This differentiated pressure application capability is achieved through the decoupling design of the mechanical structure, rather than relying solely on the control algorithm, thereby ensuring the reliability and accuracy of load application in long-term rheological experiments. Through the coordinated cooperation of the box, partitioned pressure plates, independent pressure application components and monitoring holes, this embodiment effectively solves the problem that traditional devices are difficult to simulate complex stress gradients and dynamic interactions between surrounding rock and support, providing a high-fidelity physical simulation platform for the study of rheological mechanisms in deep underground engineering.

[0026] Example 2: Figures 1-15 As shown, the box body includes a bottom plate 1, and two side plates 2 are vertically arranged on the bottom plate 1. The bottom of the two side plates 2 are fixed to the bottom plate 1 by a locking structure. The upper ends of the two side plates 2 are fixed together by a tie rod 12. Multiple displacement side holes 9 are opened on one of the side plates 2. A water tank 39 is provided on the bottom plate 1. The water tank 39 is fixedly connected to an industrial camera 40a through a first bracket. The lens of the industrial camera 40a is aimed at the displacement side holes 9, and digital speckle technology is used to monitor the horizontal and vertical displacement of the surrounding rock simulation material 13 in the displacement side holes 9. The working principle of the above technical solution is as follows: The base plate 1 serves as the supporting base of the entire device and is usually made of thick steel plate to ensure flatness; the two side plates 2 stand parallel on the base plate 1 and together with the base plate 1 form a U-shaped trough space to accommodate the surrounding rock simulation material 13. The tie rod 12 is connected across the top of the two side plates 2, and its two ends can be locked to the side plates 2 by means of thread fastening or pin connection. This upper lateral constraint can effectively counteract the external tension torque generated by the lateral expansion of the internal material of the side plates 2 during the experimental loading process, prevent the box opening from deforming, and thus maintain the geometric stability of the boundary conditions. Displacement side holes 9 are spaced apart along the height or length of side plate 2, providing a physical channel for monitoring deformation at different depths within the surrounding rock. Water tank 39 is installed on the base plate 1, serving two purposes: firstly, by utilizing the weight of water to increase the counterweight at the bottom of the device, improving overall anti-overturning stability; secondly, as a hydraulic medium source, it connects to an external injection and drainage system via pipelines, providing a continuously adjustable liquid load for subsequent pressure components. The lens of industrial camera 40a is aimed at the displacement side holes 9, and digital speckle technology is used to perform non-contact, full-field displacement monitoring of the surrounding rock simulation material 13 within the displacement side holes 9. Specifically, digital speckle technology uses pre-prepared artificial speckle patterns on the surface of the surrounding rock simulation material 13 or utilizes the material's own natural texture features as an information carrier. The industrial camera 40a continuously acquires speckle image sequences before and after deformation, and then uses digital image correlation algorithms to perform sub-pixel-level matching and correlation calculations on image sub-regions, thereby accurately obtaining the horizontal and vertical displacement components of the surrounding rock simulation material 13 at the displacement side holes 9. Compared to the single-point contact measurement of traditional rod displacement gauges, digital speckle technology does not require physical contact with the measuring point, avoiding the local interference and additional stress caused by contact sensors on the surface of the object being measured. At the same time, it can acquire displacement data in both horizontal and vertical directions simultaneously, significantly improving monitoring efficiency and data dimensionality. It can capture the full-field deformation evolution process of the surrounding rock surface in real time and continuously. A transparent acrylic plate is provided between the side plate 2 with displacement side hole 9 and the surrounding rock simulation material 13. The transparent acrylic plate can prevent the surrounding rock simulation material 13 from being squeezed out from the displacement side hole 9. At the same time, the digital speckle technology of the industrial camera can be used in the displacement side hole 9 to penetrate the transparent acrylic plate and monitor the horizontal and vertical displacement of the surrounding rock simulation material 13. The deep surrounding rock rheological simulation experiment is a typical "long-term constant static load" experiment, not a high-frequency dynamic fatigue or impact experiment. After the counterweight barrel completes the initial meshing of the teeth (convex tooth 34 and tooth groove 28) by gravity, the entire system remains in a static hanging state for several days, without generating high-frequency relative friction and impact. There is no wear and gap increase problem caused by repeated impact. In addition, a water tank 39 is specially set on the bottom plate 1. The water tank not only serves as a liquid storage container, but its huge self-weight directly presses on the bottom plate, significantly increasing the counterweight at the bottom of the device, thereby greatly improving the overall anti-overturning stability. The transparent acrylic sheet is sandwiched between the side plate and the surrounding rock material to cover the displacement side hole 9 and prevent material extrusion. Under the strong rigid back support of the external steel side plate, the acrylic sheet will not undergo significant bending deformation that changes the overall boundary conditions of the model. In actual experiments, those skilled in the art can completely overcome optical noise and obtain high-precision data by using an industrial camera 40a and combining appropriate light source arrangement and light-transmitting material selection.

[0027] Example 3: Figures 1-15As shown, the locking structure includes a support screw 3, which is fixed on the base plate 1. The support screw 3 slides in the long groove 4 provided on the side plate 2. Both sides of the long groove 4 are fixed with lower positioning plates 5 by locking screws 6. The lower positioning plate 5 is provided with a first protrusion tooth. The support screw 3 is threadedly connected to a tightening nut 8. The lower end of the tightening nut 8 is inserted into the upper end of the upper positioning plate 7. The upper positioning plate 7 is sleeved on the outside of the support screw 3. The lower end of the upper positioning plate 7 is provided with a second protrusion tooth. The first protrusion tooth and the second protrusion tooth mesh. The working principle of the above technical solution is as follows: The support screw 3 is vertically welded or fixed to the base plate 1 at a preset position through an interference fit. The long groove 4 at the bottom of the side plate 2 is sleeved on the outside of the support screw 3, so that the side plate 2 can be adjusted laterally relative to the base plate 1 along the extension direction of the long groove 4. The lower positioning plate 5 is fastened to the bottom surface of the side plate 2 by the locking screw 6 and moves synchronously with the side plate 2. The first protrusion on its upper surface is usually a sawtooth or trapezoidal tooth arranged along the adjustment direction. The upper positioning plate 7 is movably sleeved on the support screw 3 and located above the side plate 2. Its lower surface is provided with a second protrusion that matches the first protrusion. When it is necessary to adjust the spacing of the side plates 2, the tightening nut 8 is loosened, and the upper positioning plate 7 is lifted upward under the action of thread retraction. The first protrusion and the second protrusion After the two sides are separated, the side plate 2 is in a free sliding state. After the side plate 2 moves to the target position, tighten the tightening nut 8. The lower end of the nut pushes the upper positioning plate 7 down, forcing the second tooth to be embedded in the tooth groove of the first tooth to form a rigid engagement. Compared with the traditional method of fixing by relying solely on the friction force generated by the nut pressing the plane, this tooth surface engagement structure directly converts the horizontal shear force on the side plate 2 into the normal pressure and shear resistance of the tooth surface, fundamentally eliminating the risk of slippage caused by the unstable friction coefficient. Especially in rheological tests that last for weeks or even months, even if the material undergoes creep relaxation or environmental vibration, the interlocking mechanism between the teeth can still maintain the absolute locking of the side plate 2 position, ensuring the high stiffness and dimensional stability of the experimental boundary conditions.

[0028] Example 4: Figures 1-15 As shown, the bottom plate 1 is fixed with an end plate 11 at one end, and the two side plates 2 are fixed to the end plate 11 by bolts. The surrounding rock simulation material 13 is placed between the two side plates 2, with one end of the surrounding rock simulation material 13 abutting against the end plate 11 and the other end of the surrounding rock simulation material 13 being inserted with a support component. The working principle of the above technical solution is as follows: the end plate 11 is set perpendicular to the bottom plate 1 and the side plate 2, and is fastened to both by high-strength bolts, forming a rigid axial boundary of the box. During experimental assembly, one end face of the surrounding rock simulation material 13 is tightly attached to the inner side of the end plate 11. The end plate 11 simulates the stable original rock mass far away from the excavation face in underground engineering, providing an immovable zero displacement reference for the model. The other end of the surrounding rock simulation material 13 serves as a free surface or support surface for installing support components such as anchor bolts. This boundary arrangement of "one end rigidly fixed and one end actively supported" truly reproduces the force asymmetry of the surrounding rock in actual engineering, making the mechanical response test of the support components closer to the on-site working conditions.

[0029] Example 5: Figures 1-15 As shown, the support assembly includes an anchor bolt 14, the front end of which is inserted into the surrounding rock simulation material 13, an anchoring agent 15 is provided between the anchor bolt 14 and the surrounding rock simulation material 13, a nut 17 is threadedly connected to the tail end of the anchor bolt 14, a tray 16 is fitted on the anchor bolt 14, the tray 16 is located between the nut 17 and the end face of the surrounding rock simulation material 13, and the side plate 2 is fixedly connected to the second tie rod displacement gauge 40b through the second bracket, and the measuring end of the second tie rod displacement gauge 40b is connected to the tail end of the anchor bolt 14; The working principle of the above technical solution is as follows: As the core component of the active support for simulating underground engineering, the insertion depth, angle, and spacing of the anchor rod 14 can be precisely set according to the design parameters of similar simulation tests to reproduce the on-site support scheme. The anchoring agent 15 is filled between the anchor rod 14 and the borehole wall of the surrounding rock simulation material 13. Its function is not only physical fixation, but more importantly, it simulates the interface bonding and shear transmission behavior between the "anchor rod-anchoring agent-surrounding rock" in real engineering in terms of mechanics. During long-term rheological tests, the surrounding rock simulation material 13 will undergo creep deformation. The anchoring agent 15 can effectively transfer this deformation to the anchor rod 14, causing the anchor rod to generate a corresponding axial force response, thereby truly reflecting the interaction mechanism between the support structure and the surrounding rock. The tray 16 is usually a metal plate or composite material plate with a certain rigidity. It is attached to the free end face of the surrounding rock simulation material 13. The tray 16 is clamped by tightening the nut 17, thereby transferring the prestressed load to the interior of the surrounding rock. This prestressing method can simulate the active restraint effect of prestressed anchor rods on the surrounding rock in engineering, improve the stress state of the surrounding rock, and inhibit crack propagation. The second rod displacement gauge 40b does not adopt the traditional method of contacting the surrounding rock surface or indirect measurement. Instead, its measuring probe is directly rigidly connected or coaxially docked with the tail end of the anchor rod 14 extending outside the housing. This direct-connection measurement structure completely eliminates systematic errors introduced by intermediate links such as local indentation of the tray 16, loosening of the nut 17, or frictional slippage of the contact surface. This ensures that the measured displacement data purely reflects the axial deformation of the anchor rod 14 itself caused by the rheology of the surrounding rock. During the rheological test, as the surrounding rock simulation material 13 continues to deform, the anchor rod 14 will be subjected to tension or compression. The second tie rod displacement gauge 40b can record this tiny axial displacement response curve in real time and continuously. Combined with the known load boundary applied by the pressure application component, researchers can use this to inversely deduce the stress evolution law of the anchor rod under long-term high stress environment, and evaluate the long-term stability and safety of the support structure. Compared with the traditional method of only monitoring the displacement of the surrounding rock surface, this direct monitoring method for the support component itself provides more direct and reliable data support for deeply revealing the collaborative bearing mechanism of "surrounding rock-support", and effectively avoids the problem of information distortion caused by excessively long measurement links.

[0030] Example 6: Figures 1-15 As shown, the pressure application assembly includes a support 18, the lower end of which is fixed to the base plate 1. The upper end of the support 18 is rotatably connected to multiple supporting outer arms 19. The lower ends of the multiple supporting outer arms 19 are respectively fixed to multiple pressure rod sleeves 20. The lower ends of the multiple pressure rod sleeves 20 are respectively threaded to multiple pressure rods 21. The lower ends of the multiple pressure rods 21 respectively abut against multiple pressure plates 10 and apply different pressures to the multiple pressure plates 10. The support 18 is fixedly connected to the third tie rod displacement gauge 40c through the third bracket. The measuring end of the third tie rod displacement gauge 40c is connected to the upper end of the pressure plate 10. The working principle of the above technical solution is as follows: Support 18 serves as the common fulcrum of the entire pressure system, securely mounted on the base plate 1, providing a unified mechanical reference for multi-channel loading. Multiple support arms 19 are arranged at intervals along the axial or circumferential direction of support 18. Each support arm 19, along with its matching pressure rod sleeve 20 and pressure rod 21, constitutes an independent loading unit. This modular design decouples the loading units from each other in the mechanical transmission path, preventing interference. The pressure rod 21 and pressure rod sleeve 20 are fitted with precision threads, allowing for precise adjustment of its extension length within the sleeve by rotating the pressure rod 21. Furthermore, the vertical distance between the bottom end of the pressure rod 21 and the supporting outer arm 19 is finely adjusted. This adjustment function has a dual purpose: on the one hand, in the initial stage of the experiment, the flatness error of the surrounding rock simulation material 13 can be compensated by independently adjusting the length of each pressure rod 21, ensuring that all pressure plates 10 are subjected to uniform force at the same time; on the other hand, during the rheological test, if significant creep settlement occurs in a certain area of ​​the surrounding rock, resulting in load relaxation, the pressure rod 21 in that area can be screwed in separately for a small amount of supplementary load without affecting the stress state of adjacent areas, thereby truly realizing independent and precise control of the differentiated pressure of multiple pressure plates 10; The third tie rod displacement gauge 40c directly monitors the vertical displacement change of the pressure plate 10. Combined with the known geometric parameters of the pressure application components and the counterweight information, the actual contact pressure acting on the surrounding rock simulation material 13 can be calculated. This integrated "pressure application-monitoring" design forms a local mechanical closed loop, effectively eliminating load transfer losses caused by mechanical clearances, elastic deformation of components, and other factors, and ensuring the accuracy and traceability of stress boundary conditions in long-term rheological experiments.

[0031] Example 7: Figures 1-15 As shown, an inner support arm 22 is slidably connected inside the outer support arm 19. The lower end of the inner support arm 22 is provided with a third protruding tooth. A toothed plate 23 is slidably connected inside the outer support arm 19. The outer support arm 19 is threadedly connected to a second locking screw 24. The upper end of the second locking screw 24 presses the toothed plate 23 to move upward inside the outer support arm 19. The fourth protruding tooth on the toothed plate 23 meshes with the third protruding tooth. The working principle of the above technical solution is as follows: The inner support arm 22 is sleeved in the cavity of the outer support arm 19 and can slide freely along the axial direction to change its extension length. According to the lever balance principle, when the counterweight is suspended at the end of the inner support arm 22, the magnitude of the load acting on the pressure plate 10 is proportional to the extension length (i.e., lever arm) of the inner support arm 22. Therefore, by adjusting the extension amount of the inner support arm 22, the load applied to the surrounding rock model can be continuously and steplessly amplified or reduced without replacing the counterweight bucket 30, which greatly improves the flexibility and applicability of the experimental device. For example, when it is necessary to simulate a deep, extremely high stress environment, the inner support arm 22 can be pulled out to its maximum stroke, and the long lever arm effect can be used to convert a small counterweight into a large model load. Conversely, when performing low stress or fine loading, shortening the lever arm can obtain high-resolution load adjustment capability. More importantly, considering that rheological tests often last for weeks or even months and the applied loads are often as high as several tons, traditional friction locking methods are prone to creep and slippage under long-term heavy loads, leading to lever arm length drift and load instability. To address this, this embodiment has specially designed a toothed locking mechanism. After the inner support arm 22 is adjusted to the target position, the locking screw 24 is tightened, and the top of the screw pushes the toothed plate 23 upward, forcing the fourth tooth on the toothed plate 23 to be tightly embedded in the third tooth at the lower end of the inner support arm 22. This rigid meshing between the tooth surfaces completely converts the horizontal shear force into the compressive and shear forces at the root of the tooth, completely eliminating the uncertainty of maintaining the position by relying on friction. Even under extreme vibration or temperature change environments, the toothed structure can still maintain the absolute locking of the position of the inner support arm 22, ensuring that the lever arm ratio remains constant, thus providing a reliable mechanical guarantee for high-precision, long-cycle rheological simulation experiments.

[0032] Example 8: As Figures 1-15 As shown, a support ring 25 is snapped onto the front end of the inner support arm 22, and a support cap 26 is fixed to the lower end of the support ring 25. The support cap 26 is connected to the counterweight barrel 30 through a gravity self-locking assembly. Two adjacent counterweight barrels 30 are connected through a gravity self-locking assembly. The upper end of the counterweight barrel 30 is provided with a water inlet, and the lower end of the counterweight barrel 30 is provided with a water outlet. Both the water inlet and the water outlet are provided with a stopcock. The water tank 39 can inject water into the counterweight barrel 30 through the water inlet, and the counterweight barrel 30 can release water into the water tank 39 through the water outlet. The working principle of the above technical solution is as follows: This embodiment uses water as the counterweight medium, completely changing the traditional loading mode of rheological testing devices that relies on the stacking of solid weights. The water tank 39 not only serves as a liquid storage container, but its own weight also presses down on the base plate 1, stabilizing the entire experimental device base and preventing the pressure-applying components from overturning or shifting during operation. By controlling the water flow between the counterweight bucket 30 and the water tank 39 through an external water pump or valve, continuous and stepless adjustment of the load can be achieved, avoiding the stress step problem caused by discrete loading of solid weights, and significantly improving the accuracy of rheological simulation. At the same time, the fluidity of water allows the center of gravity of the counterweight bucket 30 to be adaptively adjusted, reducing the additional bending moment caused by eccentric loading. It should be understood that although water is preferably used as the medium in this embodiment, in other embodiments, oil, salt water, or other liquids with stable density can also be selected according to experimental requirements, as long as the function of fluid statics transfer and mass regulation can be achieved.

[0033] Example 9: Figures 1-15 As shown, the gravity self-locking assembly includes an outer slip ring 31, which slides on the outside of the counterweight barrel 30 port. Both sides of the outer slip ring 31 are provided with outer protrusions 32. A spring 35 is provided between the outer slip ring 31 and the counterweight barrel 30. An inner slip ring 37 is slidably connected to the upper end of the counterweight barrel 30. A sealing ring 36 is provided at the upper end of the inner slip ring 37. The lower end of the inner slip ring 37 is fixedly connected to the outer slip ring 31 through multiple support rods 38. All the multiple support rods 38 slide inside the counterweight barrel 30. Both sides of the counterweight barrel 30 are provided with locking blocks 33. Both locking blocks 33 slide on the bottom of the outer slip ring 31. The lower end of both locking blocks 33 is provided with protruding teeth 34. The lower end of the support cap 26 is open. The edge of the opening is provided with two inner bosses 27. One end of the inner boss 27 is set with an inclined surface. The other end of the inner boss 27 is provided with a baffle 29. The inner boss 27 is provided with a tooth groove 28. The upper end of the counterweight barrel 30 is inserted into the support cap 26. The sealing ring 36 abuts against the top of the support cap 26. When the counterweight barrel 30 is rotated, the two outer bosses 32 are respectively locked onto the two inner bosses 27. After water is filled into the counterweight barrel 30, the counterweight barrel 30 moves down and the protruding teeth 34 engage with the tooth groove 28 to lock it. The working principle of the above technical solution is as follows: The inner slip ring 37 and the outer slip ring 31 form a rigid linkage through the support rod 38 passing through the side wall of the counterweight barrel 30, so that the two can slide synchronously along the axial direction of the counterweight barrel 30. The spring 35 is sleeved on the support rod 38 or the outer wall of the counterweight barrel 30, and its two ends abut against the limiting steps of the outer slip ring 31 and the counterweight barrel 30, respectively, providing an upward restoring force. When the barrel is empty or the preset load is not reached, the spring force of the spring 35 is greater than the sum of the weight of the counterweight barrel 30 and its internal components, forcing the outer slip ring 37 to slide synchronously along the axial direction of the counterweight barrel 30. The slip ring 31 and inner slip ring 37 are held in the initial position at the top. The sealing ring 36 is installed on the top of the inner slip ring 37 to provide a sealing interface when the counterweight bucket 30 and the support cap 26 are engaged, preventing liquid leakage during water injection from affecting the counterweight accuracy. This design establishes a direct physical coupling relationship between the "locking action" and the "load size". Only when the injected water volume reaches a certain threshold and gravity overcomes the preset elastic force of the spring 35 will the subsequent locking stroke be triggered, thereby realizing adaptive safety control based on the load state. During installation, the operator inserts the upper end of the empty counterweight bucket 30 into the support cap 26. At this time, the sealing ring 36 is pre-pressed against the top of the support cap 26 to form a preliminary seal. Then, the counterweight bucket 30 is rotated, which drives the outer slip ring 31 and its outer protrusion 32 to rotate. The outer protrusion 32 slides along the inclined surface of the inner protrusion 27 and engages below the inner protrusion 27, completing the initial axial engagement. Since there is no water or very little water in the bucket at this time, the gravity is insufficient to overcome the elastic force of the spring 35. The protruding tooth 34 at the lower end of the locking block 33 is separated from the tooth groove 28 on the inner protrusion 27, and the counterweight bucket 30 can still rotate relative to it. When water is injected into the counterweight bucket 30 through the water inlet, the total weight of the bucket gradually increases. Once the gravity exceeds the critical elastic force of the spring 35, the counterweight bucket 30, along with the outer slip ring 31 and the inner slip ring 37, will engage. The entire structure moves downward, compressing the spring 35. During the downward movement, the locking block 33 moves down synchronously with the outer slip ring 31, forcing the protruding tooth 34 at its lower end to embed into the tooth groove 28 on the inner boss 27 of the support cap 26, forming a rigid circumferential anti-rotation lock and axial load-bearing lock. This "water-filled locking" mechanism ensures that the counterweight bucket 30 is only firmly locked under load, completely eliminating the risk of accidental detachment under heavy load. When unloading, simply open the outlet to drain water. As the water volume decreases and the gravity decreases, the spring 35 pushes the outer slip ring 31 to reset and move upward, and the protruding tooth 34 automatically disengages from the tooth groove 28, releasing the lock. At this time, the counterweight bucket 30 can be easily disassembled simply by rotating it in the opposite direction. The entire process does not require any manual locking tools or additional operating steps, which not only ensures extremely high safety but also greatly improves experimental efficiency. The inner slip ring 37 at the upper end of the counterweight barrel 30 is equipped with a sealing ring 36. When the upper end of the counterweight barrel is inserted into the support cap 26, the sealing ring 36 directly abuts against the top of the support cap 26 to form a sealing interface. This physical sealing structure effectively blocks the convection and evaporation of water inside the barrel from the outside. The core safety mechanism of this device is "gravity self-locking". When water is injected into the counterweight tank 30 to make the gravity reach the threshold and move downward, the protruding tooth 34 at the lower end of the locking block 33 will directly embed into the tooth groove 28 of the inner boss 27 to form a rigid engagement and lock. Once the locking is completed, most of the downward mechanical load of the counterweight is directly borne by the rigid tooth groove structure (inner boss 27 and protruding tooth 34). The spring 35 only plays a triggering role at the moment when the water reaches the threshold (a very short time). During the long rheological experiment, the spring is not the main load-bearing component. Therefore, its long-term pressure creep is not only negligible, but will also not affect the fixed rigid locking state and the load accuracy of the experiment. As a professional large-scale scientific research instrument for "deep high-stress surrounding rock rheology", the precise assembly, local manual leveling and thread pre-tightening in the early stage of the experiment are extremely normal and necessary standard steps in geotechnical engineering tests. The core of "automation" and "burden reduction" in this application is that in the dangerous heavy load test process and load compensation stage, stepless continuous loading is achieved by using a water tank with 39 injections and drainage combined with a self-locking mechanism. This completely eliminates the extremely high labor intensity and the risk of injury or death caused by the long-term and frequent manual handling of solid weights weighing several tons in traditional devices. The solution is logically rigorous and structurally complete, and can be manufactured and put into use in industry or laboratory.

[0034] Two adjacent counterweight barrels 30 are installed in the same way. Each counterweight barrel 30 has an opening at its bottom, with two inner bosses 27 on the edge of the opening. One end of each inner boss 27 has a bevel, and the other end has a baffle 29. Each inner boss 27 has a toothed groove 28. The lower counterweight barrel 30 is inserted into the opening of the upper counterweight barrel 30. Rotating the lower counterweight barrel 30 engages and locks the two counterweight barrels 30, enabling rapid adjustment of the counterweight of the pressure component. This means that each counterweight barrel 30 is both a load unit and a connection interface, possessing standardized cascading expansion capabilities. The bottom structure of the upper counterweight barrel 30 is completely identical to the lower structure of the support cap 26, both having inner bosses 27 with bevels and toothed grooves 28. The top structure of the lower counterweight barrel 30 is the same as the standard counterweight barrel 30, featuring an outer slip ring 31, an outer boss 32, and a locking block 33. Therefore, multiple… The counterweight buckets 30 can be stacked vertically like building blocks, and each level of connection follows the same "rotational hooking + gravity self-locking" logic. When a larger load is required, simply stack the counterweight buckets 30 one by one and fill them with water. The locking action of each level is triggered independently by its own gravity and does not interfere with each other. This modular design allows the load adjustment range of the pressure application components to be flexibly expanded according to experimental needs without the need to replace levers or counterweights of different specifications. At the same time, since the locking force comes from gravity itself, the more layers are stacked, the greater the load borne by the lower bucket, and the more reliable its locking becomes, forming a natural positive feedback safety mechanism. It should be understood that although the figure shows the form of a cylindrical counterweight bucket 30, in other embodiments, the counterweight bucket 30 can also be designed as a square, polygonal or other shape, as long as its port has a matching self-locking interface structure, the above-mentioned cascade locking function can be realized.

[0035] It is understood that the present invention has been described through some embodiments, and those skilled in the art will recognize that various changes or equivalent substitutions can be made to these features and embodiments without departing from the spirit and scope of the invention. Furthermore, under the teachings of the present invention, these features and embodiments can be modified to adapt to specific situations and materials without departing from the spirit and scope of the invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the protection scope of the present invention.

Claims

1. A rheological simulation experimental device for high-stress surrounding rock and support structure in underground engineering, characterized in that, The box includes a surrounding rock simulation material (13) placed inside the box. A support component is inserted into the surrounding rock simulation material (13). Multiple pressure plates (10) are provided on the upper end of the surrounding rock simulation material (13). Multiple displacement side holes (9) are opened on the side of the box. A pressure application component is installed on the side of the box. The lower end of the pressure application component abuts against multiple pressure plates (10). The pressure application component can apply different pressures to multiple pressure plates (10). The box includes a bottom plate (1), and two side plates (2) are vertically arranged on the bottom plate (1). The bottom of the two side plates (2) are fixed to the bottom plate (1) by a locking structure. The upper ends of the two side plates (2) are fixed together by a tie rod (12). Multiple displacement side holes (9) are opened on one of the side plates (2). A water tank (39) is provided on the bottom plate (1). The water tank (39) is fixedly connected to an industrial camera (40a) through a first bracket. The lens of the industrial camera (40a) is aligned with the displacement side hole (9). Digital speckle technology is used to monitor the horizontal and vertical displacement of the surrounding rock simulation material (13) in the displacement side hole (9). The pressure application assembly includes a support (18), the lower end of which is fixed to the base plate (1), and the upper end of which is rotatably connected to multiple support arms (19). The lower ends of the multiple support arms (19) are respectively fixed to multiple pressure rod sleeves (20), and the lower ends of the multiple pressure rod sleeves (20) are respectively threaded to multiple pressure rods (21). The lower ends of the multiple pressure rods (21) respectively abut against multiple pressure plates (10) and apply different pressures to the multiple pressure plates (10). The support (18) is fixedly connected to the third tie rod displacement gauge (40c) through the third bracket. The measuring end of the third tie rod displacement gauge (40c) is connected to the upper end of the pressure plate (10). The inner support arm (22) is slidably connected to the outer support arm (19). The lower end of the inner support arm (22) is provided with a third tooth. The toothed plate (23) is slidably connected to the outer support arm (19). The outer support arm (19) is threadedly connected to the second locking screw (24). The upper end of the second locking screw (24) presses the toothed plate (23) to move upward inside the outer support arm (19). The fourth tooth on the toothed plate (23) meshes with the third tooth.

2. The rheological simulation experimental device for high-stress surrounding rock and support structure in underground engineering according to claim 1, characterized in that, The locking structure includes a support screw (3), which is fixed on the base plate (1). The support screw (3) slides in the long groove (4) provided on the side plate (2). Both sides of the long groove (4) are fixed with a lower positioning plate (5) by a locking screw (6). The lower positioning plate (5) is provided with a first protrusion. The support screw (3) is threadedly connected to the tightening nut (8). The lower end of the tightening nut (8) is inserted into the upper end of the upper positioning plate (7). The upper positioning plate (7) is sleeved on the outside of the support screw (3). The lower end of the upper positioning plate (7) is provided with a second protrusion. The first protrusion and the second protrusion mesh.

3. The rheological simulation experimental device for high-stress surrounding rock and support structure in underground engineering according to claim 2, characterized in that, The bottom plate (1) is fixed with an end plate (11) at one end. Both side plates (2) are fixed to the end plate (11) by bolts. The surrounding rock simulation material (13) is placed between the two side plates (2). One end of the surrounding rock simulation material (13) rests on the end plate (11), and the other end of the surrounding rock simulation material (13) is connected to a support component.

4. The rheological simulation experimental device for high-stress surrounding rock and support structure in underground engineering according to claim 3, characterized in that, The support assembly includes an anchor rod (14), the front end of which is inserted into the surrounding rock simulation material (13), and an anchoring agent (15) is provided between the anchor rod (14) and the surrounding rock simulation material (13). A nut (17) is threadedly connected to the tail end of the anchor rod (14). A tray (16) is fitted on the anchor rod (14), and the tray (16) is located between the nut (17) and the end face of the surrounding rock simulation material (13). The side plate (2) is fixedly connected to the second tie rod displacement gauge (40b) through the second bracket, and the measuring end of the second tie rod displacement gauge (40b) is connected to the tail end of the anchor rod (14).

5. The rheological simulation experimental device for high-stress surrounding rock and support structure in underground engineering according to claim 1, characterized in that, The front end of the inner support arm (22) is snapped with a support ring (25), and the lower end of the support ring (25) is fixed with a support cap (26). The support cap (26) is connected to the counterweight barrel (30) through a gravity self-locking assembly. The upper and lower adjacent counterweight barrels (30) are connected through a gravity self-locking assembly. The upper end of the counterweight barrel (30) is provided with a water inlet, and the lower end of the counterweight barrel (30) is provided with a water outlet. Both the water inlet and the water outlet are provided with a stopcock. The water tank (39) can inject water into the counterweight barrel (30) through the water inlet, and the counterweight barrel (30) can release water into the water tank (39) through the water outlet.

6. The rheological simulation experimental device for high-stress surrounding rock and support structure in underground engineering according to claim 5, characterized in that, The gravity self-locking assembly includes an outer slip ring (31), which slides on the outside of the counterweight barrel (30) port. Both sides of the outer slip ring (31) are provided with outer bosses (32). A spring (35) is provided between the outer slip ring (31) and the counterweight barrel (30). An inner slip ring (37) is slidably connected to the upper end of the counterweight barrel (30). A sealing ring (36) is provided at the upper end of the inner slip ring (37). The lower end of the inner slip ring (37) is fixedly connected to the outer slip ring (31) through multiple support rods (38). All the support rods (38) slide inside the counterweight barrel (30).

7. The rheological simulation experimental device for high-stress surrounding rock and support structure in underground engineering according to claim 6, characterized in that, The counterweight barrel (30) is provided with locking blocks (33) on both sides. Both locking blocks (33) slide on the bottom of the outer slip ring (31). Both locking blocks (33) are provided with protruding teeth (34) at the lower end. The support cap (26) has an opening at the lower end. The opening edge is provided with two inner bosses (27). One end of the inner boss (27) is set with an inclined surface. The other end of the inner boss (27) is provided with a baffle (29). The inner boss (27) is provided with a tooth groove (28). The upper end of the counterweight barrel (30) is inserted into the support cap (26). The sealing ring (36) abuts against the top of the support cap (26). The counterweight barrel (30) is rotated. The two outer bosses (32) are respectively locked onto the two inner bosses (27). After water is injected into the counterweight barrel (30), the counterweight barrel (30) moves down. The protruding teeth (34) and the tooth groove (28) mesh and lock.

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