Bolt construction device and method for large-scale geomechanics physical simulation tests

Abstract

The present invention discloses an anchor rod construction device and method for large-scale geomechanical physical simulation tests. It consists of a fixed guiding system, a rotary propulsion system, a telescopic clamping system, and a power control system. The fixed guiding system includes a U-shaped frame and a sliding rod, which are used to fix the drilling device and provide a sliding platform for the telescopic clamping system; the rotary propulsion system includes a roller screw and a servo motor, which can achieve the steady drilling of a slender anchor rod during the rotation process; the telescopic clamping system includes a telescopic rod, a chuck, a rotating cone, and a clamping frame, which are used to clamp the slender anchor rod for rotation and drilling. The power control system includes a console, an air pump, and a servo motor, which provide a power source for the slender anchor rod. The present invention can achieve the drilling of slender anchor rods in any orientation such as the side wall and vault of a tunnel in a model test, and can truly restore the anchoring and support process of an actual tunnel project, providing technical support for carrying out large-scale physical simulation tests to deeply study the stability of the anchoring and support of underground projects.

Description

Technical Field

[0001] This invention relates to the field of model testing in water conservancy and hydropower, transportation and mining engineering, and in particular to anchor bolt construction devices and operating methods for physical simulation tests of anchoring mechanisms in tunnel engineering. Background Technology

[0002] The "anchor-mesh-sprayed" combined support system, as an important component of the New Austrian Tunneling Method (NATM), plays a crucial role in the initial support of tunnel engineering. Current research on anchoring mechanisms mainly relies on on-site pull-out tests and monitoring the axial force of anchor bolts, but these methods suffer from drawbacks such as long cycles, high risks, and high costs. In contrast, numerical simulation is the most flexible, convenient, and time-saving method, but its parameter values ​​and boundary conditions are difficult to keep consistent with actual engineering projects, thus compromising the accuracy and effectiveness of the simulation results. Model tests have the advantage of realistically reproducing the characteristics of rock mass occurrence. Successful zonal fracturing experiments have demonstrated that model tests can reproduce new discoveries in real-world deep geotechnical engineering.

[0003] Conducting geomechanical and physical simulation tests is one of the important technical means to study the mechanism of rock and soil anchoring support. Existing anchoring model tests with large geometric similarity scales often involve pre-embedding anchor rods in the model, which is clearly inconsistent with reality and thus affects the accuracy of the results. The reason for pre-embedding anchor rods is that the large geometric similarity scale results in a small tunnel model size, leading to limited construction space and necessitating pre-embedding of anchor rods. Current research trends suggest reducing the geometric similarity scale, which allows for a larger tunnel model opening size, making it possible to conduct model experiments where the opening is drilled first and then the anchor is added. However, this leads to a problem: the large slenderness ratio of the model anchor rods makes them prone to buckling during drilling. Therefore, a major technical bottleneck is the lack of an effective anchor rod construction device for large-scale geomechanical and physical simulation tests.

[0004] The current research status of anchor bolt construction simulation methods in relevant model tests both domestically and internationally is as follows:

[0005] The journal "Rock and Soil Mechanics" (Volume 42, Issue 4, 2021) introduces a method for pull-out model tests of pre-embedded grouting support type anchor bolts. This method involves placing the anchor bolts in a preset position during the model construction and then continuing to fill the model with clay. This method can accurately locate the construction position and tilt direction of the anchor bolts and is suitable for slope support model tests. However, the pre-embedding of the anchor bolts does not conform to the actual construction procedures.

[0006] The invention patent with application number CN201810980901.X developed a true three-dimensional geomechanical model test anchor bolt pre-embedding device and operation method, which solved the shortcomings of difficult anchor bolt installation, inaccurate positioning and limited installation range in true three-dimensional geomechanical model test. However, the device completes the anchor bolt pre-embedding before filling the model body, which can easily cause the anchoring system to have an interface with the surrounding rock, resulting in a discrepancy with the actual surrounding rock occurrence environment.

[0007] The invention patent with application number CN202111023524.9 developed a device and method for anchor positioning in geomechanical model tests, which solved the problem of inaccurate anchor positioning in geomechanical model tests. However, the device uses a lifting mechanism to push the anchor into the tunnel model, which will inevitably damage the surrounding rock of the tunnel, resulting in a discrepancy with the actual construction method. Summary of the Invention

[0008] The purpose of this invention is to overcome the shortcomings of the existing technology and provide an anchor bolt construction device and operation method for large-scale geomechanical physical simulation tests. This device can automatically drill into the slender model anchor bolt, reproduce the real tunnel anchoring process, and ensure that the synergistic stress deformation mechanism of the tunnel wall surrounding rock and the anchoring system is consistent with the actual engineering. At the same time, it can also realize the automation and intelligence of anchoring support in large-scale geomechanical physical simulation tests.

[0009] The technical solution adopted by this invention to solve its technical problem is:

[0010] An anchor bolt construction device for large-scale geomechanical physical simulation tests includes a fixed guiding system, a rotary propulsion system, a telescopic clamping system, and a power control system;

[0011] The fixed guiding system includes a U-shaped frame and two sliding rods. The U-shaped frame is used to fix the drilling device. The two sliding rods are parallel to each other and fixed inside the U-shaped frame. The two sliding rods provide the running track for the model anchor.

[0012] The rotary propulsion system includes a lead screw and a servo motor. The lead screw is arranged parallel to the axis of the slide rod. The bottom end of the lead screw is fixedly connected to the rotating shaft of the first servo motor, and the top end is movably connected to the U-shaped frame. The lead screw is threaded through the clamping frame, and the telescopic clamping system is moved on it.

[0013] The telescopic clamping system includes a telescopic rod, a clamp, a rotating cone, and a clamping frame. The clamp is fixed to the top of the telescopic rod and has a cylindrical groove in the middle, with its axis aligned with the axis of the rotating cone. This groove is used to clamp a slender anchor rod for eccentric rotation to drill into the cavity wall of the model body. The bottom of the telescopic rod is fixed to the rotating cone and connected to an air pump. The rotating cone is connected to the clamping frame via ball bearings. The rotating cone is controlled by a second servo motor.

[0014] The power control system includes a control console, which is connected to the air pump, the first servo motor, the second servo motor, and the clamp fixed on the telescopic rod via wires, and is used to control the air pressure of the air pump, the speed of the servo motor, and the opening and closing of the clamp.

[0015] Specifically, the structure of each system is described below:

[0016] More preferably, the U-shaped frame is fixedly connected to the tunnel surface.

[0017] In a further preferred embodiment, the slide bar and the clamping frame are connected by a threaded connection, providing a sliding track for the rotary propulsion system.

[0018] In a further preferred embodiment, the telescopic rod is connected to the rotating cone, the bottom of the telescopic rod is connected to the air pipe, and the wire passes through the cavity of the telescopic rod and connects to the clamp at the top of the telescopic rod.

[0019] More preferably, the telescopic rods include two, which are arranged in parallel; the clamps include two, which are fixed on the two telescopic rods respectively, and the two clamps are arranged at different heights in the vertical direction. Each clamp has a cylindrical groove, the axis of which is consistent with the axis of the rotating cone. The surface of the groove is rough to hold the model anchor rod to rotate around its axis; the two clamps are used to hold the model anchor rod to rotate without eccentricity to drill into the surrounding rock of the model body cave wall.

[0020] More preferably, the air pump is connected to the telescopic rod via an air pipe to control the air pressure inside the telescopic rod to achieve the extension and retraction of the telescopic rod.

[0021] In a further preferred embodiment, the controller connects to the servo motor via wires to control the rotation state of the servo motor.

[0022] The method for drilling slender anchor bolts using this invention in large-scale geomechanical physical simulation tests is as follows:

[0023] (1) Design the construction plan and drilling depth of the model anchor bolt, and assemble the slender anchor bolt drilling device according to the construction plan;

[0024] (2) Filling and loading for geomechanical and physical simulation tests; after loading is completed, excavation is carried out to form a model tunnel;

[0025] (3) Push the assembled slender anchor drilling device into the designed position of the model tunnel in a timely manner.

[0026] (4) Set the drilling program of the controller and send instructions to start the air pump and the first servo motor and the second servo motor to perform anchoring simulation.

[0027] The beneficial effects of the above embodiments of the present invention are as follows:

[0028] (1) The anchor bolt construction device proposed in this invention for large-scale geomechanical physical simulation test has a combined fixed guidance system, a rotary propulsion system, a telescopic clamping system and a power control system. Through the cooperation between these systems, the process of anchor bolt drilling into the surrounding rock of tunnel wall can be realistically reproduced. The fixed guidance system can strictly control the angle of anchor bolt drilling.

[0029] (2) The upper and lower clamps of the present invention, together with the telescopic rod, can stably drill the model anchor into the surrounding rock of the tunnel wall, so that the model test can truly restore the cooperative force characteristics of the anchor and the surrounding rock of the tunnel wall, avoiding the drawbacks of pre-embedded model anchors in the traditional large geometric scale type anchoring mechanism model test.

[0030] (3) The telescopic rod in this invention is a hollow closed structure, and its bottom is connected to an air pump. The telescopic rod can be extended and retracted by controlling the air pressure inside. The wire passes through the hollow cavity of the telescopic rod and is connected to the clamp fixed at the top to control the opening and closing of the clamp.

[0031] (4) The controller in this invention is connected to the air pump and the first servo motor and the second servo motor through wires, and can control the working state of the air pump and the servo motor by inputting commands. Attached Figure Description

[0032] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0033] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0034] Figure 2 This is a schematic diagram of the fixed guide system of the present invention;

[0035] Figure 3 This is a schematic diagram of the rotary propulsion system of the present invention;

[0036] Figure 4 This is a schematic diagram of the telescopic clamping system of the present invention;

[0037] Figure 5 This is a schematic diagram of the power control system of the present invention.

[0038] Among them, 1. U-shaped groove, 2. slide bar, 3. roller screw, 4. servo motor, 5. telescopic rod, 6. clamp, 7. rotating cone, 8. clamping frame, 9. controller, 10. air pump, 11. rolling bearing, 12. wire, 13. air pipe, 14. model anchor rod. Detailed Implementation

[0039] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0040] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0041] For ease of description, the words "up," "down," "left," and "right" appearing in this application only indicate that they are consistent with the up, down, left, and right directions of the drawings themselves, and do not limit the structure. They are merely for the purpose of facilitating the description of the invention and 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 this application.

[0042] Terminology Explanation: The terms "installation," "connection," and "fixation" in this application should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction relationship between two components. Those skilled in the art can understand the meaning of the above terms in this invention according to the specific circumstances.

[0043] As noted in the background section, drilling slender anchor bolts is a key technical challenge in anchoring mechanism model tests. Domestic and international model tests often involve pre-embedding the anchor bolts within the model body, which obviously leads to a mismatch between model tests and actual engineering anchor bolt drilling methods. Therefore, this application proposes an anchor bolt construction device and operating method for large-scale geomechanical physical simulation tests. This device enables automatic drilling of slender anchor bolts into the tunnel wall surrounding rock during model tests, and allows for simultaneous drilling of the entire anchor bolt system. Furthermore, the device is robust and reliable, has a low cost, simple construction, convenient operation, good safety, and can be used for large-scale geomechanical physical simulation tests.

[0044] In one typical implementation of this application, such as Figures 1 to 5 As shown in the figure, this embodiment discloses an anchor bolt construction device for large-scale geomechanical physical simulation tests, including a fixed guiding system, a rotary propulsion system, a telescopic clamping system, and a power control system, wherein:

[0045] Depend on Figures 1 to 5 As shown, the above-mentioned fixed guide system consists of a U-shaped frame 1 and two sliding rods 2; after the U-shaped frame 1 tilts to one side, one of its side walls serves as the bottom and is fixed to the ground of the model tunnel, and the two sliding rods 2 are vertically fixed inside the U-shaped frame 1; the two sliding rods 2 mainly serve to initiate the guide function.

[0046] The rotary propulsion system includes a lead screw 3 and a servo motor 4. The lead screw 3 is installed between two slide rods 2, and the axis of the lead screw 3 is parallel to that of the two slide rods 2. The bottom of the lead screw 3 is connected to the rotation shaft of the first servo motor 4, and the top of the lead screw 3 is movably connected to the top of the U-shaped frame 1 (i.e., the top of the lead screw 3 can rotate within the U-shaped frame 1). The clamping frame 8 is smoothly connected to the two slide rods 2, and the clamping frame 8 is threadedly connected to the lead screw 3 (i.e., as the lead screw 3 rotates, the clamping frame 8 can move along the axis of the lead screw, corresponding to the attached...). Figure 1 (For vertical movement).

[0047] Furthermore, the aforementioned telescopic clamping system includes a clamping frame 8, a telescopic rod 5, a clamp 6, a rotating cone 7, and a rolling bearing 11. The rotating cone 7 is connected to the clamping frame 8 via the rolling bearing 11. A second servo motor 4 is installed at the bottom of the clamping frame 8. The second servo motor 4 is connected to the rotating cone 7 and drives the rotating cone 7 to rotate. Simultaneously, the bottom of the telescopic rod 5 is connected to the rotating cone 7, and the clamp 6 is installed at the top of the telescopic rod 5. The clamp 6 can clamp and rotate the model anchor rod 14. The main purpose of the telescopic clamping system is to control the rotation of the rotating cone 7 through the second servo motor 4, thereby allowing the model anchor rod 14 to drill into the surrounding rock of the tunnel wall.

[0048] Furthermore, the aforementioned clamp 6 has a cylindrical groove whose axis is aligned with the axis of the rotating cone 7, used to clamp the model anchor rod 14 for non-eccentric rotation to drill into the surrounding rock of the model body cave wall; and the surface of the cylindrical groove is rough, which can increase the friction between it and the model anchor rod 14.

[0049] Furthermore, the surface of the model anchor rod 14 is provided with drill bit threads to facilitate drilling into the surrounding rock of the model tunnel wall.

[0050] Furthermore, two clamps 6 and two telescopic rods 5 are provided. The two telescopic rods 5 are parallel to each other and are both installed on the rotating cone 7. The two telescopic rods 5 are separated by a certain distance in the height direction (i.e., one telescopic rod is longer and the other is shorter). One clamp 6 is installed on one telescopic rod 5 and another clamp 6 is installed on the other telescopic rod 5. The two clamps 6 are installed vertically. During the drilling of the model anchor rod 14, in order to avoid the instability of the rod, it is considered to use the two clamps 6, which are staggered by a certain distance, to clamp the head of the model anchor rod 14. As the model anchor rod 14 is drilled, when the chuck 6 is close to the tunnel wall, the first servo motor 4 stops. Then, the higher chuck 6 opens, and the air pump 10 draws air from the telescopic rod 5 to reduce its pressure, allowing the telescopic rod 5 to retract. After retracting a certain distance, the higher chuck 6 clamps again, and the lower chuck 6 opens. The air pump 10 again draws air from the telescopic rod 5 to reduce its internal pressure, allowing the telescopic rod 5 to retract. After retracting a certain distance, the lower chuck 6 clamps again. At this point, the second servo motor 4 starts rotating, and the model anchor rod 14 rotates and drills in again. This process repeats until the entire model anchor rod is drilled into the surrounding rock of the model tunnel wall, completing the drilling of the slender anchor rod.

[0051] Furthermore, the aforementioned telescopic rod 5 is a hollow, closed structure, with its bottom connected to an air pump. The telescopic rod's extension and retraction are achieved by controlling the internal air pressure. A wire passes through the hollow cavity of the telescopic rod and connects to a clamp fixed at the top to control the opening and closing of the clamp 6.

[0052] The present invention provides an operation method for drilling slender anchor bolts for geomechanical physical simulation experiments:

[0053] (1) Design the construction plan and drilling depth of the slender model 14, and assemble the slender anchor drilling device according to the construction plan;

[0054] (2) Filling and loading for geomechanical and physical simulation tests; after loading is completed, excavation is carried out to form a model tunnel;

[0055] (3) Push the assembled slender anchor drilling device into the designated position of the model tunnel in a timely manner;

[0056] (4) Set the drilling program of the controller and send the command to the servo motor 4 and automatically control the start of the air pump 10 to drill the model anchor rod 14.

[0057] (5) Open the clamp 6, reverse the roller screw 3, retract the telescopic clamping system, pull out the anchor bolt construction device, and complete the anchor bolt construction.

[0058] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent transformations, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An anchor bolt construction device for large-scale geomechanical physical simulation tests, characterized in that, It includes a fixed guiding system, a rotary propulsion system, a telescopic clamping system, and a power control system; among which: The fixed guiding system includes a U-shaped frame and a sliding rod. The U-shaped frame is fixed to the tunnel surface at an arbitrary set angle. The sliding rod is vertically fixed inside the U-shaped frame. The telescopic clamping system is sleeved on the sliding rod and can slide along the axis of the sliding rod. The rotary propulsion system includes a ball screw and a servo motor. The ball screw is installed in a U-shaped frame, and one end of the ball screw is driven by a first servo motor. The clamping frame is threadedly engaged with the ball screw. The telescopic clamping system moves in the opposite direction of its axis by rotating the ball screw itself. The telescopic clamping system includes a telescopic rod, clamps, a rotating cone, and a clamping frame. The clamps are used to clamp the model anchor rods and are fixed to the top of the telescopic rod. The bottom of the telescopic rod is fixed to the rotating cone, which is connected to the clamping frame via ball bearings. The telescopic rod is controlled by an air pump, and the rotating cone is controlled by a second servo motor. There are two telescopic rods arranged in parallel. There are two clamps, each fixed to one of the two telescopic rods, and the two clamps are arranged at different heights in the vertical direction. The power control system includes a control console, which is connected to an air pump, a first servo motor, a second servo motor, and a clamp fixed on the telescopic rod via wires. The control console is used to control the air pressure of the air pump, the rotation state of the first servo motor and the second servo motor, and the opening and closing of the clamp.

2. The anchor bolt construction device for large-scale geomechanical physical simulation tests according to claim 1, characterized in that, The model anchor is made of metal.

3. The anchor bolt construction device for large-scale geomechanical physical simulation tests according to claim 1, characterized in that, Each clamp has a cylindrical groove, and the axes of the two cylindrical grooves are aligned with the axis of the rotating cone. This is used to clamp the model anchor rod for non-eccentric rotation to drill into the surrounding rock of the model cavity. The surface of the groove is rough, and the clamping model anchor rod rotates around its axis.

4. The anchor bolt construction device for large-scale geomechanical physical simulation tests according to claim 1, characterized in that, The bottom of the telescopic rod is connected to an air pump via an air pipe. The air pump injects and evacuates air into the telescopic tube to change the internal air pressure, thereby achieving the telescopic rod's extension and retraction.

5. A method for drilling using the anchor bolt construction device for large-scale geomechanical physical simulation tests as described in any one of claims 1-4, characterized in that, include: (1) Design the drilling depth of slender anchor bolts and set up the anchor bolt construction device according to the construction plan; (2) Filling and loading for geomechanical and physical simulation tests. After loading is completed, excavation is carried out to form a model tunnel; (3) Assemble the slender anchor drilling device and place it at the designed position; (4) Set the drilling program of the controller and send the command to start the air pump and the first servo motor and the second servo motor to drill the slender anchor rod; (5) Open the clamp, reverse the roller screw, retract the telescopic clamping system, and pull out the anchor bolt construction device.

6. The method for drilling using the anchor bolt construction device for large-scale geomechanical physical simulation tests according to claim 5, characterized in that, During the rotary drilling of the slender anchor rod, both chucks are in a clamped state. After the slender anchor rod has drilled a certain distance into the tunnel wall, the higher chuck opens and is moved down by the telescopic rod connected to it. When it approaches the lower chuck, it is tightened again. The lower chuck also opens and moves down the same distance before being tightened again. This alternating action is used to achieve the segmented drilling of the slender anchor rod.

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