A mobile impact device for indoor simulation tests of rock mass excavation

Abstract

This invention relates to a mobile impact device for indoor simulation tests of rock excavation. Electric slide rails are installed on both longitudinal sides of the model box. A slider connected to the bottom of the truss allows longitudinal movement, while electric slide rails are installed on the truss beams, allowing the slider connected to the impact device to move laterally. An adjustment device is located inside the frame, with a screw and nut built into its adjustment frame. Rotating the screw knob drives the nut to rise or fall. The inner and outer adjustment frames are welded together via a connecting frame I; rotating the outer knob drives the inner adjustment frame to rise or fall. A stabilizing device is located between the two inner adjustment frames, and a modal exciter is placed between the two inner adjustment frames and connected to the nut inside the inner adjustment frame. Rotating the inner knob drives the raising and lowering. A laser displacement sensor monitors the excavation depth in real time, and a pressure sensor monitors the specimen reaction force, collaboratively controlling the operation of the modal exciter. This device is suitable for continuous excavation of large specimens at multiple points. An industrial control computer enables automatic cyclic excavation, and dual-sensor redundant monitoring controls the depth, reducing manual intervention and improving experimental efficiency and accuracy.

Description

Technical Field

[0001] This utility model relates to the field of indoor simulation test technology for rock mass excavation, specifically a mobile impact device for indoor simulation test of rock mass excavation. Background Technology

[0002] The study of stress redistribution caused by rock mass excavation disturbance is an important scientific issue for the safe construction of underground engineering. During excavation, the original stress balance of the rock mass is broken, and the stress state of the surrounding rock undergoes secondary redistribution, causing the initiation and expansion of internal cracks in the rock mass, which can easily induce surrounding rock fracturing, rock bursts, or even collapse disasters.

[0003] The underground engineering model test method, based on similarity theory, scales down actual engineering projects into models, obtains data through model tests, and derives conclusions. It has now become one of the core research methods in the field of underground engineering.

[0004] Existing rock excavation simulation test devices are mostly designed for small-sized specimens, relying on manual start / stop or preset fixed start / stop nodes for the excavation process, making them unsuitable for the complex excavation requirements of large-sized specimens. Their movement systems are mostly single-axis manual adjustment or fixed path control, unable to achieve continuous multi-point movement and excavation, resulting in low test efficiency, large errors in point spacing, and the potential for operational deviations due to manual intervention. Furthermore, traditional devices struggle to synchronously coordinate excavation start / stop and movement actions, failing to reproduce the dynamic advancement process of the excavation face in real engineering projects, thus limiting the accuracy of large-scale specimen tests for studying geological patterns. Summary of the Invention

[0005] To solve the above-mentioned technical problems, this utility model provides a mobile impact device for indoor simulation tests of rock mass excavation, the technical solution of which is as follows: A vertical impact system is installed on the mobile system. This vertical impact system includes a frame, adjustment devices, stabilizing devices, and a modal exciter. The frame consists of two horizontal bars and two vertical bars, with the horizontal bars and vertical bars fixedly connected and fixedly connected to the slider on the moving system. The adjustment device is located inside the frame and includes an adjustment frame, a screw, a nut, and a knob; Each adjustment frame is equipped with a screw, a nut is fixed on the screw, and a knob is located on the top of each screw, which is located on the outside of the adjustment frame. The two outer adjustment frames are fixedly connected to the longitudinal bars of the frame, and the tops of the two inner adjustment frames are fixedly connected by two other horizontal bars. The nuts on the two outer adjusting frames are respectively connected and fixed to the two inner adjusting frames through the connecting bracket I; A stabilizing device is installed between the two inner adjustment frames. The stabilizing device consists of a connecting frame II, a modal exciter, a push rod, a six-tooth punch drill bit, and a pressure sensor. The two ends of the connecting frame II are fixedly connected to the nuts of the two inner adjustment frames respectively. The modal exciter is installed inside the connecting frame II. The modal exciter is located at the top of the push rod, and the six-tooth punch drill bit is installed at the bottom of the push rod. A pressure sensor is also provided between the six-tooth punch drill bit and the push rod.

[0006] Furthermore, a laser displacement sensor is installed at the bottom of the connecting frame II.

[0007] Furthermore, a suction pipe is installed at the bottom of the inner adjustment frame on one side, with the pipe opening facing the six-tooth punch drill bit.

[0008] Furthermore, the six-tooth punch drill bit uses a cone as its base, with six protruding wedge-shaped teeth evenly distributed along the circumference of the cone surface. The teeth are evenly distributed on the cone surface with a apex angle of 60°. The root of the teeth is integrally formed with the cone surface, or connected by a high-strength welding method.

[0009] Furthermore, the pressure sensor is installed between the top rod and the six-tooth punch drill bit to collect the reaction force of the sample on the top rod during excavation in real time, serving as a redundant monitoring unit of the laser displacement sensor to assist in controlling the excavation depth.

[0010] Furthermore, the moving system includes an electric slide rail and a truss. The electric slide rail is a transverse electric slide rail and a longitudinal electric slide rail. The bottom of the truss is connected to the slider and is mounted on the longitudinal electric slide rail. The truss beam is provided with a transverse electric slide rail, on which a slider is mounted, and a fixed frame is mounted on the slider.

[0011] The beneficial effects of this utility model are as follows: 1. This utility model is a mobile impact device for indoor simulation test of rock excavation. It simulates the planar advancement process to realize dynamic excavation. By combining the excavation device with the mobile system, the excavation is automated and the depth error between various points is reduced. It is easy to operate and has high test accuracy.

[0012] 2. This utility model has automatic movement and continuous start-stop coordination functions to meet the needs of dynamic excavation tests of large specimens at multiple points. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the overall structure of the present invention after installation; Figure 2 This is a schematic diagram of the mobile system structure of this utility model; Figure 3 This is a schematic diagram of the vertical impact system of this utility model; Figure 4 for Figure 3 A schematic diagram of the split structure; Figure 5 This is a circuit block diagram of the present invention.

[0014] As shown in the figure: 1-Model box; 2-Moving system, 201-Truss, 202-Longitudinal electric slide rail, 203-Transverse electric slide rail; 3-Vertical impact system, 301-Frame, 302-Knob, 303-Nut, 304-Connecting frame I, 305-Modal exciter, 306-Screw, 307-Stabilizing device, 308-Laser displacement sensor, 309-Pressure sensor, 310-Six-tooth punch drill bit, 311-Industrial vacuum cleaner, 312-Adjusting frame, 313-Top rod, 314-Connecting frame II. Detailed Implementation

[0015] As shown in the figure, this utility model is a mobile impact device for indoor simulation test of rock excavation. The mobile system 2 and the vertical impact system 3 are both set above the model box 1.

[0016] 1. For example Figure 1 As shown, model box 1 is used for casting the sample. The model box is a cuboid with an open top. During the casting process, similar materials are cast in layers according to the set parameters and compacted by vibration. After the sample is formed, a square groove is excavated at the preset detection position using a handheld electric drill equipped with a cutting drill bit. The strain gauges, miniature earth pressure cells, and other detection sensors are attached to the inside of the groove near the excavation side. The groove is then filled, avoiding the subsequent excavation path. The flatness of the top surface of the sample is checked. If there are obvious protrusions or tilts, they should be manually ground flat. If there are depressions, they should be filled in time. The excavation area line is drawn on the top surface of the sample using a tape measure and a chalk line, and the excavation path is marked.

[0017] 2. The moving system 2 is located above the model box 1, such as... Figure 2 As shown, the system includes a truss 201, longitudinal electric slide rails 202, and transverse electric slide rails 203. The bottom legs of the truss 201 are connected to the sliders of the longitudinal electric slide rails 202. The two longitudinal electric slide rails 202 are located on the left and right sides of the model box exterior, arranged along the length of the box. The two transverse electric slide rails 203 are located on the top of the truss, arranged along the width of the box. The sliders of the transverse electric slide rails 203 are connected to the vertical impact system. Limiting blocks are provided at both ends of the electric slide rails to prevent the sliders from sliding out.

[0018] 3. For example Figure 3 and 4As shown, the vertical impact system 3 is centrally mounted on the moving system 2, including a frame 301, a knob 302, a nut 303, a connecting frame I 304, a modal vibrator 305, a screw 306, a stabilizing device 307, a laser displacement sensor 308, a pressure sensor 309, a six-tooth punch drill bit 310, and an industrial vacuum cleaner 311 (Kärcher IVS100 / 40LP vacuum cleaner model can be selected; the industrial vacuum cleaner pipe is installed at the center of the bottom of the left inner adjustment frame, with the suction inlet aligned with the drill bit and spaced a certain distance apart to ensure that the vacuum cleaner does not obstruct the work of the drill bit when cleaning debris) and an adjustment frame 312. The frame 301 is composed of four steel plates (i.e., two horizontal bars and two vertical bars) connected by bolts to form a rectangular frame structure. Each steel plate has four screw holes at both ends to connect other steel plates and fix them to the slider. Four adjustment frames 312 are arranged side-by-side inside the frame. The two outer adjustment frames 312 are welded to two longitudinal steel plates of the device frame 301. The knobs are connected to the screws and installed on the top of the adjustment frames. The outer nuts are welded to the top of the inner adjustment frames via connecting bracket I304. The tops of the two inner adjustment frames are connected and fixed via additional crossbars and matching bolts. The nuts inside the two inner adjustment frames are welded and fixed to the connecting bracket II314 of the stabilizing device (connecting bracket II connects the vibrator and prevents the top rod from shaking). The pressure sensor (using a Spartacus SBT650 push-pull force sensor) is installed between the top rod and the six-tooth punch drill bit to collect the reaction force of the sample on the top rod during excavation in real time. It serves as a redundant monitoring unit of the laser displacement sensor to assist in controlling the excavation depth. When the excavation depth exceeds the limit, causing the drill bit to fail to contact the sample, the pressure sensor detects a sudden drop in reaction force and triggers the industrial control computer system to immediately shut down the vibrator. The six-tooth punch drill bit uses a cone as its base, with six raised wedge-shaped teeth evenly distributed along the circumference of the cone surface. The teeth are evenly distributed on the cone surface with a apex angle of 60°. The root of the teeth is integrally formed with the cone surface or connected by high-strength welding. By adding six raised teeth, the stress is dispersed, reducing the generation of large debris during excavation.

[0019] The vertical impact system 3 is used to adjust the height of the six-tooth punch drill bit 310 and to excavate the sample; the stabilizing device includes a modal vibrator and a top rod; the top center plate of the connecting frame II is bolted to the bottom hole of the modal vibrator. The modal vibrator is an existing device, model B&K4824 from Denmark. A locking seat and a locking nut are fitted on the top rod 313 of the modal vibrator. By rotating the locking nut forward and backward, the locking seat clamps or loosens the top rod, thereby adjusting the extension distance of the top rod. Adjusting the locking nut fixes the extension length of the top rod of the modal vibrator 305.

[0020] Start the electric slide rails 202 and 203, and move the moving truss 201 and the vertical impact system 3 to the starting point according to the preset path. After stopping, manually adjust the knob 302 to adjust the height of the six-tooth punch drill bit 310 to above the sample rock mass. The distance between the drill bit and the sample surface is the extension length of the modal exciter top rod minus the single-layer excavation depth. Start the laser displacement sensor 308 (CMD-DE400ES / X model, set on one side below the connecting frame II, with the rangefinder transmitter vertically irradiating and attached to the outer edge of the drill bit), and complete the initial distance measurement by irradiating the sample surface with laser.

[0021] The modal vibrator 305 performs a test strike on the starting point (the test strike is to adjust the impact rate, and then the groove is measured to obtain the spacing of the impact points after the test strike). After the excavation is completed, the groove caused by the excavation is manually measured, and two points on the edge of the groove opening are selected as feature points. These two points should be able to stably reflect the spatial position of the groove (such as the edge extreme point along the excavation path). By measuring the distance between these two points multiple times and taking the average value, the distance between adjacent excavation points can be accurately determined. The same groove is measured more than 3 times and the average value is taken as the point spacing.

[0022] 4. For example Figure 5 As shown, the industrial control computer system undertakes the overall data processing and control functions: the laser displacement sensor transmits depth data via RS485 bus, and the pressure sensor transmits reaction force data after signal conditioning. After analysis and comparison, if the industrial control computer determines that the depth error reaches ±5% or the reaction force drops sharply, it immediately sends a stop signal to shut down the vibrator. After the vibrator stops, the industrial control computer sends a point movement command to the motion control card, driving the movement system to move the excavation device to the next point. After the movement stops, the electric slide rail feeds back the actual position through the encoder, and the industrial control computer controls the deviation correction (automatic fine-tuning when it exceeds ±1mm). Once the position is accurate, a start signal is sent to activate the vibrator, completing one excavation-movement cycle. The vibrator frequency is preset and adjusted according to the response speed of the laser displacement sensor before the test and remains fixed during operation.

[0023] Input the preset excavation path and point spacing into the industrial control computer system, and then transmit the signals to the motion control card. Adjust the impact frequency of the modal exciter 305. During excavation, use the maximum response speed of the laser displacement sensor as a benchmark, and set the upper limit of the modal exciter 305 frequency with a 10%-20% margin. Gradually increase the frequency through pre-tests. If the data from the laser displacement sensor 308 shows jumps, lags, or errors exceeding ±5%, reduce the frequency. Within the acceptable frequency range, select the optimal impact speed that balances distance measurement accuracy and excavation efficiency, taking into account the target single-layer excavation depth. The industrial vacuum cleaner 311 and modal vibrator 305 are started, and excavation begins according to the preset program. During excavation, the laser displacement sensor 308 measures and records the depth of the excavation point in real time. When the excavation depth is detected to reach ±5% of the preset value for each layer and the pressure sensor 309 (connected in series between the top rod and the six-tooth punch drill bit, collecting the reaction force of the sample on the top rod in real time during excavation, serving as a redundant monitoring unit of the laser displacement sensor to assist in controlling the excavation depth) detects a sudden drop in reaction force, the industrial control computer system is triggered to immediately shut down the vibrator.

[0024] During the excavation process, the changes in strain and stress inside the sample detected by the pre-embedded earth pressure cell, strain gauge, and acoustic emission sensor are sent to the industrial control computer system for real-time recording.

[0025] Depending on the actual situation, after each layer of excavation is completed, the remaining rubble should be cleaned up. The flatness after excavation should be relatively flat. If there is a large protrusion, the vertical impact system 3 should be manually controlled to strike the part a second time. If there is a large depression, it should be filled to ensure the flatness after excavation. After passing the test, manually adjust the knob 302 to adjust the six-tooth punch drill bit 310 to the next layer elevation and continue the operation. Repeat the above excavation process until the overall excavation is completed.

[0026] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features of the present invention.

Claims

1. A mobile impact device for indoor simulation test of rock mass excavation, a vertical impact system is installed on a moving system, characterized in that, The vertical impact system includes a frame, adjustment device, stabilization device, and modal exciter; The frame consists of two horizontal bars and two vertical bars, with the horizontal bars and vertical bars fixedly connected and fixedly connected to the slider on the moving system. The adjustment device is located inside the frame and includes an adjustment frame, a screw, a nut, and a knob; Each adjustment frame is equipped with a screw, a nut is fixed on the screw, and a knob is located on the top of each screw, which is located on the outside of the adjustment frame. The two outer adjustment frames are fixedly connected to the longitudinal bars of the frame, and the tops of the two inner adjustment frames are fixedly connected by two other horizontal bars. The nuts on the two outer adjusting frames are respectively connected and fixed to the two inner adjusting frames through the connecting bracket I; A stabilizing device is installed between the two inner adjustment frames. The stabilizing device consists of a connecting frame II, a modal exciter, a push rod, a six-tooth punch drill bit, and a pressure sensor. The two ends of the connecting frame II are fixedly connected to the nuts of the two inner adjustment frames respectively. The modal exciter is installed inside the connecting frame II. The modal exciter is set at the top of the push rod, and the six-tooth punch drill bit is installed at the bottom of the push rod. A pressure sensor is also provided between the six-tooth punch drill bit and the push rod.

2. A mobile impact device for use in a simulation test of rock mass excavation according to claim 1, characterized in that, The moving system includes an electric slide rail and a truss. The electric slide rail is a transverse electric slide rail and a longitudinal electric slide rail. The bottom of the truss is connected to the slider and is set on the longitudinal electric slide rail. The truss beam is provided with a transverse electric slide rail, and a slider is set on the slide rail. A fixed frame is on the slider.

3. The mobile impact device for indoor simulation testing of rock excavation as described in claim 1, characterized in that, A laser displacement sensor is installed at the bottom of connector II.

4. The mobile impact device for indoor simulation testing of rock excavation as described in claim 1, characterized in that, Install a suction pipe at the bottom of the inner adjustment frame on one side, with the pipe opening facing the six-tooth punch drill bit.

5. A mobile impact device for indoor simulation testing of rock excavation as described in claim 1, characterized in that, The six-tooth punch drill bit uses a cone as its base, with six protruding wedge-shaped teeth evenly distributed along the circumference of the cone surface. The teeth are evenly distributed on the cone surface with a apex angle of 60°. The root of the teeth is integrally formed with the cone surface, or connected by a high-strength welding method.

6. The mobile impact device for indoor simulation testing of rock excavation as described in claim 1, characterized in that, The pressure sensor is installed between the top rod and the six-tooth punch drill bit to collect the reaction force of the sample on the top rod during excavation in real time, and serves as a redundant monitoring unit of the laser displacement sensor to assist in controlling the excavation depth.

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