A test device for rock shear creep impact disturbance loading

Abstract

The present application relates to the field of rock mechanics property testing, and discloses a test device for rock shear creep impact disturbance loading. The device comprises a control box, an air compressor, a fixed plate, a pressure sensor, a fixed base, an air cylinder, a speed regulating throttle valve, an anti-rotation rod, an anti-rotation plate and a ram. The control box is connected with the pressure sensor and the air compressor through wires; the loading end of the pressure sensor is connected with the fixed base, and the base is installed on the fixed plate; the rear end cover of the air cylinder is connected with the fixed base, and the piston rod end is connected with the ram; the lower part of the ram is provided with an anti-rotation rod connecting lug, and the anti-rotation rod is fixed with the anti-rotation plate through the connecting lug. The air compressor is connected with the speed regulating throttle valve, the ram reciprocating motion is controlled by adjusting air pressure through the control box, and shear impact disturbance loading is realized. The present application can simulate real disturbance working conditions such as blasting and earthquake, has intelligent regulation and control functions of disturbance frequency and load, and is suitable for rock shear creep impact disturbance test.

Description

Technical Field

[0001] This invention relates to the field of rock mechanical property testing, specifically to a test apparatus for rock shear creep impact disturbance loading. Background Technology

[0002] In geotechnical engineering fields such as mineral resource extraction, water conservancy and hydropower projects, and underground space development, rock masses are subjected to high geostress environments for extended periods, resulting in significant creep effects. Simultaneously, natural events such as engineering blasting, mechanical vibration, and earthquakes cause frequent dynamic disturbances to the rock mass. This coupling effect of "static creep" and "dynamic disturbance" is a key mechanism inducing geological disasters such as rock mass instability, rockbursts, and landslides. Therefore, realistically and accurately simulating the mechanical behavior of rock under dynamic disturbances throughout the entire shear creep process under laboratory conditions is crucial for revealing its failure mechanisms and assessing the long-term stability of engineering rock masses.

[0003] Currently, conventional rock shear creep testing machines primarily focus on applying constant or progressively increasing static shear loads to observe the steady-state creep and accelerated creep stages of rock samples. However, they generally lack the ability to simultaneously apply controllable dynamic disturbance loads during the creep process. Existing dynamic loading devices, such as drop hammer impacts and servo-hydraulic vibration tables, while capable of generating impact or vibration loads, often struggle to effectively integrate with rock shear creep testing machines in terms of loading direction, action mode (especially the vector superposition with static shear loads), frequency, and independent and precise control of load. Consequently, they cannot accurately simulate the complex conditions under which the shear surface is subjected to normal or tangential disturbances during creep.

[0004] Furthermore, existing technologies suffer from insufficient precision in controlling the frequency and load of impact disturbances, making it difficult to achieve fine-tuning at levels such as 0.1 Hz frequency accuracy and ±1 N load accuracy. This results in large dispersion in experimental data, making it impossible to accurately establish a quantitative relationship between specific disturbance parameters and rock shear creep characteristics. Therefore, developing a dedicated impact disturbance loading device that can work in conjunction with a shear creep testing machine and provide intelligent, precise, and independent control of the disturbance frequency and load has become a pressing technical problem in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a test device for impact disturbance loading of rock shear creep. This device can be used in conjunction with a rock shear box, applying reciprocating impact disturbances along the shear direction during rock shear creep tests. The frequency and load of these disturbances can be independently controlled with high precision, effectively simulating real disturbance conditions such as blasting and earthquakes, and providing reliable equipment support for refined experimental research on the static-dynamic coupled mechanical behavior of rocks.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A test apparatus for impact disturbance loading of rock shear creep includes: a control box; an air compressor electrically connected to the control box; and an impact disturbance loading device including: a fixed plate, which is an irregularly shaped cast steel plate with mounting holes adapted to a pressure sensor on its surface; the pressure sensor, whose base is detachably mounted on the surface of the fixed plate by bolts, with the loading end facing forward; a fixed base, which is a rod-shaped integral structure, with a mating structure at its lower end precisely connected to the loading end of the pressure sensor, and an annular flange at its upper end, coaxially fixedly connected to the rear end cover of a cylinder; the cylinder is a double-acting cylinder, with its piston rod end detachably connected to a striking block by a threaded structure; the striking block is used to apply impact disturbance to the shear creep specimen; and an anti-rotation rod and an anti-rotation plate. One end of the anti-rotation rod passes through the threaded through hole of the integrally formed connecting lug at the bottom of the impact block, and the other end passes through the through hole on the surface of the anti-rotation plate and is fastened with a nut to ensure that the cylinder will not deflect during high-frequency movement; the speed regulating valve is connected to the air inlet of the air compressor through a pressure-resistant air pipe, and the air outlet of the speed regulating valve is connected to the air port of the cylinder; the control box controls the cylinder to drive the impact block to perform precise reciprocating motion by adjusting the output air pressure of the air compressor and the opening of the speed regulating valve, so as to realize the impact disturbance loading on the rock sample placed in the shear box; the pressure sensor is used to collect the impact load signal applied by the impact block in real time and feed it back to the control box to form a closed-loop control.

[0008] The technical performance indicators that the device can achieve are: disturbance frequency adjustment range 0~10 Hz, frequency control accuracy 0.1 Hz; disturbance load adjustment range 0~300 N, load control accuracy ±1 N.

[0009] Compared with the prior art, the present invention has the following significant advantages:

[0010] 1. High functional integration: This invention integrates a pneumatic impact loading unit, a high-precision force measuring unit, and an intelligent control unit into one unit, which can be directly and seamlessly connected with existing rock shear creep testing systems, realizing the function of synchronously applying dynamic impact disturbance during static shear creep.

[0011] 2. Excellent control precision: By adopting an electronically controlled speed-regulating throttle valve and a high-response pressure sensor, combined with a closed-loop control algorithm based on a programmable logic controller (PLC), independent, precise and intelligent control of the impact disturbance frequency (accuracy up to 0.1 Hz) and load (accuracy up to ±1 N) is achieved, meeting the requirements of scientific research for fine-tuning of disturbance parameters.

[0012] 3. Stable and reliable structure: The core force transmission component is a one-piece molded rod-shaped fixed base, ensuring that the force transmission path from the pressure sensor to the cylinder is coaxial and has good rigidity. The unique anti-rotation rod and anti-rotation plate mechanism effectively suppresses the lateral sway that may be generated by high-frequency reciprocating motion, ensuring the uniqueness and accuracy of the impact load direction.

[0013] 4. Realistic simulation of working conditions: The controllable reciprocating impact generated by the device can accurately simulate the repeated loading and unloading disturbance effects on the rock shear surface caused by blasting stress waves and seismic vibrations in actual engineering, providing an effective experimental means for studying the failure mechanism of rocks under complex stress paths.

[0014] 5. Intelligent and data-driven operation: The control box is equipped with a human-machine interface, which can easily set test parameters, display loading curves in real time, and automatically store all test data, greatly improving test efficiency and data reliability. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the experimental device of the present invention;

[0016] Figure 2 This is a detailed structural diagram of the impact disturbance loading device;

[0017] Figure 3 A front view schematic diagram of the assembly position of the impact disturbance loading device and the shear box;

[0018] Figure 4 This is a three-dimensional schematic diagram showing the assembly position of the impact disturbance loading device and the shear box.

[0019] In the diagram: 1. Control box; 2. Air compressor; 3. Impact disturbance loading device; 3-1. Fixing plate; 3-2. Pressure sensor; 3-3. Fixing base; 3-4. Speed ​​regulating throttle valve; 3-5. Cylinder; 3-6. Anti-rotation rod; 3-7. Anti-rotation plate; 3-8. Impact block; 4. Shear box. Detailed Implementation

[0020] To better understand the present invention, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] Example 1:

[0022] like Figure 1As shown, the present invention provides a test device for rock shear creep impact disturbance loading, which mainly consists of three parts: control box 1, air compressor 2 and impact disturbance loading device 3.

[0023] Control box 1 serves as the core of the entire device, integrating a programmable logic controller (PLC), a high-precision data acquisition module, and a human-machine interface. The PLC executes the preset control logic and sends control commands to the air compressor 2 and the speed control valve 3-4. The data acquisition module is responsible for high-speed acquisition of the analog voltage signal fed back by the pressure sensor 3-2 and converting it into digital quantities for system processing and storage. The human-machine interface provides a user-friendly operating environment, allowing test personnel to directly set the target disturbance frequency (e.g., 5 Hz) and target impact load (e.g., 150 N) on the interface, and monitor key test information such as load-time curves and frequency feedback values ​​in real time.

[0024] Air compressor 2 is an oil-free, silent compressor with variable frequency speed control and stable pressure output. It can provide clean, stable, and pressure-adjustable compressed air according to the instructions of control box 1. Its outlet is connected to the inlet of the speed regulating valve 3-4 of the impact disturbance loading device 3 through a pressure-resistant air pipe.

[0025] The impact disturbance loading device 3 is the core mechanical unit that performs the impact action. Its mounting base is a fixed plate 3-1 made of an irregularly shaped cast steel plate. The fixed plate is fixed to the test bench by its irregular contour and pre-set mounting holes. The surface is machined with a group of precise mounting holes to provide a precise positioning reference for the subsequent installation of components.

[0026] The high-precision resistance strain gauge pressure sensor 3-2 is fixed to the surface of the mounting plate 3-1 by its mounting flange and bolts, with its loading end facing forward.

[0027] A rod-shaped fixed base 3-3, integrally machined from high-strength alloy steel, forms the core of the force transmission mechanism. Its lower end is machined into a precision stepped cylindrical structure, inserted into the interface hole at the center of the loading end of the pressure sensor 3-2, and locked with a positioning screw to achieve a gapless, precise connection and reliable force transmission. Its upper end is machined with an annular flange and a recessed positioning groove. The rear end cap of a standard double-acting cylinder 3-5 fits perfectly into this positioning groove, and bolts are used to firmly fix the cylinder rear end cap to the flange at the upper end of the fixed base 3-3, ensuring strict coaxiality between the cylinder axis and the force-bearing axis of the pressure sensor.

[0028] The piston rod of cylinder 3-5 has external threads machined at its front end. The impact block 3-8 is made of high-strength alloy steel, and its rear end has a corresponding threaded blind hole, allowing for detachable connection to the piston rod end via threads. The lower part of the impact block 3-8 is integrally cast with a connecting lug containing a threaded through hole.

[0029] To ensure that when the cylinder 3-5 drives the impact block 3-8 in high-frequency (up to 10Hz) reciprocating motion, the piston rod and the impact block move only along the axial direction without any rotation or lateral oscillation, this invention features a unique anti-rotation mechanism. This mechanism includes a cast steel anti-rotation rod 3-6 with a rust-proof surface and a rectangular anti-rotation plate 3-7. One end of the anti-rotation rod 3-6 passes through a threaded through-hole in the lower part of the impact block 3-8; the other end passes through a through-hole machined on the anti-rotation plate 3-7 (the diameter of the through-hole and the diameter of the anti-rotation rod 3-6 are fitted with a small clearance), and is then locked with a nut to form a stable anti-rotation constraint.

[0030] The speed control valve 3-4 is an electronically controlled proportional valve. Its inlet is connected to the air compressor 2 via an air pipe, and its two outlets are connected to the two air ports of cylinder 3-5 via air pipes to control the extension and retraction of the cylinder. The opening degree of this valve can be continuously and precisely adjusted by the analog signal output from the PLC of the control box 1, thereby controlling the gas flow rate entering and exiting the cylinder.

[0031] The specific operating steps of the experimental device of the present invention are as follows:

[0032] 1. Sample preparation: Place the prepared rock sample into the cavity of the shear box 4, place the shear box 4 on the test station, and adjust the position so that the impact end face of the impact block 3-8 is parallel and aligned with the center position of the upper shear box side of the shear box 4.

[0033] 2. Parameter settings: The test personnel input the impact disturbance frequency and impact load required for this test on the human-machine interface of control box 1.

[0034] 3. Start-up loading: Start the air compressor 2. The PLC in the control box 1 changes the frequency of cylinder reversal by adjusting the control signal output to the speed regulating valve 3-4 according to the set disturbance frequency, and drives the impact block 3-8 to perform reciprocating impact motion at the target frequency.

[0035] 4. Closed-loop control: During the impact process, pressure sensor 3-2 monitors the actual load value of each impact in real time and quickly feeds the signal back to control box 1. The control algorithm in the PLC compares the actual load value with the target load value in real time. If there is a deviation, the output air pressure of air compressor 2 or the opening of speed regulating throttle valve 3-4 is immediately fine-tuned to ensure that the actual load of the next impact disturbance accurately reaches the target value. This closed-loop control ensures that even if the external conditions change slightly during the entire test, the disturbance load applied to the sample remains stable within the set accuracy range of ±1N.

[0036] 5. Data Recording: All data, including time, actual impact frequency, and actual impact load, are recorded and stored synchronously by the data acquisition module throughout the test, providing complete data support for subsequent analysis of the shear creep characteristics of rocks under specific disturbance parameters.

[0037] Through the above-mentioned device and method, the present invention successfully achieved the goal of applying high-precision and controllable dynamic disturbance to rock samples during shear creep, providing an advanced experimental tool for further revealing the dynamic instability mechanism of rock mass.

[0038] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, improvements, etc., made by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A test apparatus for rock shear creep impact disturbance loading, characterized in that, include: Control box (1); An air compressor (2) is electrically connected to the control box (1); an impact disturbance loading device (3) includes: a fixed plate (3-1), which is an irregularly shaped cast steel plate with a fixed mounting hole adapted to the pressure sensor (3-2) on its surface; the pressure sensor (3-2) has its base detachably mounted on the surface of the fixed plate (3-1) by bolts, with the loading end facing forward; a fixed base (3-3), which is a rod-shaped integral structure, with a mating structure at its lower end that is precisely connected to the loading end of the pressure sensor (3-2), and an annular flange at its upper end that is coaxially fixedly connected to the rear end cover of the cylinder (3-5); the cylinder (3-5) is a double-acting cylinder, with its piston rod end detachably connected to the impact block (3-8) through a threaded structure; the impact block (3-8) is used to apply impact disturbance to the shear creep sample; an anti-rotation rod (3-6) and an anti-rotation plate (3-7), the anti-rotation rod (3-6) and the anti-rotation plate (3-7) are used to apply impact disturbance to the shear creep sample. One end of the cylinder (3-6) is inserted into the threaded through hole of the integrally formed connecting ear at the lower part of the impact block (3-8), and the other end is inserted into the through hole on the surface of the anti-rotation plate (3-7) and fastened with a nut to ensure that the cylinder will not deflect during high-frequency movement; the speed regulating valve (3-4) is connected to the air inlet of the speed regulating valve (3-4) through a pressure-resistant air pipe, and the air outlet of the speed regulating valve (3-4) is connected to the air outlet of the cylinder (3-5); the control box (1) controls the cylinder (3-5) to drive the impact block (3-8) to reciprocate by adjusting the output air pressure of the air compressor (2) and the opening of the speed regulating valve (3-4), thereby realizing the impact disturbance loading on the rock sample in the shear box (4); the pressure sensor (3-2) is used to collect the impact load signal in real time and feed it back to the control box (1). The technical parameters of the device are: disturbance frequency 0~10 Hz, disturbance frequency accuracy 0.1 Hz, disturbance load 0~300 N, and disturbance load accuracy ±1 N.

2. The experimental apparatus according to claim 1, characterized in that: The fixing plate (3-1) is made of cast steel and its irregular shape is adapted to the installation space of the test bench. The distribution of the circular mounting holes on its surface matches the mounting flange of the pressure sensor (3-2).

3. The experimental apparatus according to claim 1, characterized in that: The pressure sensor (3-2) is a high-precision resistance strain gauge sensor with fast response capability and can output analog signals to the control box (1) for loading data analysis and storage.

4. The test apparatus according to claim 1, characterized in that: The fixed base (3-3) is a rod-shaped integral structure. Its lower end is inserted into the loading end hole of the pressure sensor (3-2) through a stepped cylindrical structure and is fixedly connected by positioning screws.

5. The test apparatus according to claim 1, characterized in that: The upper end of the fixed base (3-3) is provided with a concave circular groove structure, which is adapted to the shape of the rear end cover of the cylinder (3-5) and is sealed and fixed by bolt connection.

6. The test apparatus according to claim 1, characterized in that: The cylinder (3-5) is a double-acting cylinder, which can realize the reciprocating impact motion of the impact block (3-8).

7. The test apparatus according to claim 1, characterized in that: The anti-rotation plate (3-7) is a rectangular plate, and the through hole on its surface is clearance-fitted with the diameter of the anti-rotation rod (3-6). The anti-rotation rod (3-6) passes through the through hole and is locked by a nut.

8. The test apparatus according to claim 1, characterized in that: The anti-rotation rod (3-6) is made of cast steel and has a rust-proof surface treatment to ensure that the cylinder (3-5) will not deflect during high-frequency operation.

9. The test apparatus according to claim 1, characterized in that: The impact block (3-8) is made of high-strength alloy steel to prevent deformation after multi-cycle impact loading. Its lower part is provided with a connecting lug that matches the anti-rotation rod (3-6), and the anti-rotation rod (3-6) is fixed by a threaded structure.

10. The test apparatus according to claim 1, characterized in that: The speed regulating throttle valve (3-4) is electrically controlled and can adjust the gas flow and pressure in real time through the control box (1) to achieve precise control of the reciprocating motion frequency and disturbance load of the impact block (3-8).

11. The test apparatus according to claim 1, characterized in that: The control box (1) is equipped with a programmable logic controller (PLC), a data acquisition module and a human-machine interface; the programmable logic controller (PLC) is used to control the output air pressure of the air compressor (2) and adjust the opening of the speed regulating throttle valve (3-4); the data acquisition module is used to collect the output signal of the pressure sensor (3-2) in real time; the human-machine interface is used to set the frequency and load parameters of the impact disturbance and display the disturbance loading curve in real time.

12. The test apparatus according to claim 1, characterized in that: The air compressor (2) is an oil-free compressor with pressure stabilization and speed regulation function, providing a clean and adjustable compressed air source to drive the impact disturbance loading device (3).

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