Rock dynamics test device and test method for synchronous superposition of dynamic and static loads

Abstract

This invention discloses a rock dynamics testing device and method for synchronous superposition of static and dynamic loads, belonging to the field of rock dynamics testing. It includes a reaction frame and a confining pressure loading mechanism. A rock sample is held between the upper and lower pressure heads of the confining pressure loading mechanism. The upper pressure head is connected to a servo cylinder for synchronous superposition of static and dynamic loads, mounted on the upper crossbeam of the reaction frame. The servo cylinder is connected to both a static load hydraulic circuit and a dynamic load hydraulic circuit. The confining pressure loading mechanism, the servo cylinder, the static load hydraulic circuit, and the dynamic load hydraulic circuit are all electrically connected to a closed-loop control system. Using this rock dynamics testing device and method for synchronous superposition of static and dynamic loads, a constant creep reference load can be maintained for a long time under stable triaxial confining pressure constraints, effectively reproducing disturbance waveforms and better reflecting the real stress environment of long-term high ground stress superimposed with random dynamic disturbances in the surrounding rock of deep underground engineering.

Description

Technical Field

[0001] This invention relates to the field of rock dynamics testing technology, and in particular to a rock dynamics testing device and method for synchronous superposition of dynamic and static loads. Background Technology

[0002] Rock is a typical viscoelastic-plastic medium, not an ideal elastic material. Under constant and continuous load, it exhibits significant time-dependent deformation, i.e., creep characteristics. For the surrounding rock of underground engineering projects, under long-term high ground stress, it typically exhibits decaying creep, stable creep, and may enter accelerated creep until failure after an initial deformation. Therefore, conducting rock creep tests under triaxial stress conditions has irreplaceable theoretical and engineering value for revealing the long-term deformation evolution law of rock, accurately determining the long-term strength of rock, clarifying the mechanism of aging damage and instability failure of surrounding rock, and quantitatively evaluating the long-term stability of underground engineering throughout its entire life cycle.

[0003] Existing conventional triaxial creep testing machines can apply axial loads to rock samples under set lateral confining pressure constraints and maintain a constant loading state for a long period, simulating the pure rheological process of rock mass under triaxial static stress. They are now widely used in fundamental research on the static creep characteristics of rocks. However, the actual stress state of surrounding rock in deep engineering projects is not a single stable static load field: engineering and natural disturbances such as tunnel excavation blasting, mechanical cutting and excavation, continuous vibration of large mining equipment, and seismic ground motion continuously act on the rock mass, superimposing multiple levels and forms of dynamic loads on top of long-term high ground stress. Such external disturbances accelerate the initiation, propagation, and penetration of microcracks within the rock, significantly increasing the creep deformation rate and significantly shortening the time for the rock mass to transition from stable creep to unstable failure. If only a pure static load triaxial creep test scheme combining constant axial pressure and constant confining pressure is used, it is impossible to reproduce the coupled stress state of deep rock mass under "long-term high ground stress + continuous dynamic disturbance," and the obtained test results cannot truly reflect the coupled mechanical response law of the rock mass.

[0004] Currently, there are two types of testing equipment capable of combining dynamic and static loads, but both have significant functional limitations: one is a rock-specific dynamic loading device, which can achieve superimposed application of dynamic and static loads (e.g., publication number CN110031321B, publication date 2020.07.07, invention title "A Rock Mechanics Testing Machine and Test Method with Superimposed Dynamic and Static Loads"). However, the development goal of this type of equipment focuses on the instantaneous dynamic response, fatigue damage, and peak failure characteristics of rocks under short-term loading, and the duration of a single test is relatively short, failing to address specific limitations. The design for continuous monitoring of the entire creep process under long-term stable load for several months is insufficient to meet the requirements of long-term rheological testing. The second option is the traditional triaxial creep testing machine (such as publication number CN211825461U, publication date 2020.10.30, invention name "New type of mechanical-hydraulic controlled triaxial creep testing machine"). The equipment can stably carry out long-term static load creep testing, but the whole machine does not have the ability to control the superimposed dynamic disturbance during the creep process, and cannot achieve synchronous coupling output of static creep reference load and dynamic disturbance load. Summary of the Invention

[0005] The purpose of this invention is to provide a rock dynamics testing device and method for synchronous superposition of dynamic and static loads, thereby solving the above-mentioned technical problems.

[0006] To achieve the above objectives, the present invention provides a rock dynamics test device for synchronous superposition of static and dynamic loads, including a reaction frame and a confining pressure loading mechanism fixed on the base of the reaction frame. The confining pressure loading mechanism holds a rock sample between the upper and lower pressure heads. The upper pressure head is connected to a servo cylinder for synchronous loading of static and dynamic loads installed on the upper crossbeam of the reaction frame. The servo cylinder for synchronous loading of static and dynamic loads is connected to a static load hydraulic circuit and a dynamic load hydraulic circuit, respectively. The confining pressure loading mechanism, the servo cylinder for synchronous loading of static and dynamic loads, the static load hydraulic circuit and the dynamic load hydraulic circuit are all electrically connected to a closed-loop control system. The servo cylinder for synchronous loading of dynamic and static loads, the upper pressure head, the rock sample, and the lower pressure head are arranged coaxially from top to bottom.

[0007] Preferably, the servo cylinder for synchronous loading of dynamic and static loads includes a cylinder body, a composite piston slidably disposed inside the cylinder body, and a piston rod connected to the composite piston. The piston rod is fixedly connected to the upper pressure head via an axial loading rod. The compound piston divides the cylinder interior into an oil inlet chamber and an oil return chamber. The oil inlet chamber is divided into a static load oil inlet chamber and a dynamic load oil inlet chamber by a first isolation sleeve that is sealed outside the piston rod. The oil return chamber is divided into a static load oil return chamber and a dynamic load oil return chamber by a second isolation sleeve that is sealed outside the piston rod. The static load oil inlet chamber is connected to the oil outlet of the static load hydraulic circuit via the static load oil inlet port opened on the cylinder body, and the oil return end of the static load hydraulic circuit is connected to the static load oil return chamber via the static load oil return port opened on the cylinder body. The dynamic load oil inlet chamber is connected to the oil outlet of the dynamic load hydraulic circuit via the dynamic load oil inlet port opened on the cylinder body, and the oil return end of the dynamic load hydraulic circuit is connected to the dynamic load oil return chamber via the dynamic load oil return port opened on the cylinder body.

[0008] Preferably, the static load hydraulic circuit includes a static load oil source, a static load servo valve, a pressure holding valve, and a static load accumulator compensator; the static load oil source, static load servo valve, and pressure holding valve are connected in series along the oil supply direction to form a static load main oil supply pipeline, and the static load accumulator compensator is bypassed and connected to the static load main oil supply pipeline downstream of the pressure holding valve; the end of the static load main oil supply pipeline is connected to the static load inlet through the static load inlet channel in the parallel manifold, and the static load return port flows back to the static load oil source in sequence through the static load return channel in the parallel manifold and the static load servo valve; The dynamic load hydraulic circuit includes a dynamic load oil source, a high and low pressure regulating component, a high frequency servo valve, a dynamic replenishing valve group, and a pulsation suppressor connected in sequence. The pulsation suppressor is connected to the dynamic load oil inlet through the dynamic load oil inlet channel in the parallel manifold, and the dynamic load oil return port is connected to the dynamic load oil source in sequence through the dynamic load oil return channel in the parallel manifold and the high frequency servo valve.

[0009] Preferably, the high and low pressure regulating components include a high-pressure accumulator and a low-pressure accumulator connected in parallel, used to instantaneously compensate for oil supply and absorb pipeline pressure pulsations during dynamic disturbance loading.

[0010] Preferably, the confining pressure loading mechanism includes a confining pressure chamber, a lower pressure head fixed to the bottom of the confining pressure chamber, and an upper pressure head disposed above the lower pressure head. The upper pressure head is fixedly connected to the bottom of the axial loading rod, and the axial loading rod is slidably connected to the top of the confining pressure chamber. The confining pressure chamber is equipped with a confining pressure inlet and a confining pressure outlet. The confining pressure inlet is connected to the outlet end of the confining pressure source via a confining pressure control valve assembly, and the confining pressure outlet is connected to the inlet of the confining pressure source.

[0011] Preferably, the present invention further includes a data acquisition mechanism, which is electrically connected to the closed-loop control system; Data collection agencies include: The confining pressure sensor is used to collect the lateral confining pressure value applied to the rock sample inside the confining pressure chamber in real time and transmit the confining pressure simulation signal to the closed-loop control system. An axial force sensor is used to detect the total axial composite load output by the superimposed composite pistons. Static load hydraulic pressure sensor and dynamic load hydraulic pressure sensor are used to collect the real-time hydraulic pressure of static load hydraulic circuit and dynamic load hydraulic circuit respectively; Displacement sensor, used to collect the axial displacement of piston rod; The rock sample strain sensor includes an axial strain measurement component and a circumferential deformation sensor, which are used to monitor the axial and circumferential local creep strain and the dynamic strain evolution data induced by disturbance of the rock sample, respectively.

[0012] Preferably, the closed-loop control system has a built-in disturbance waveform generation module, which is used to generate a standard disturbance waveform or an engineering measured disturbance waveform according to the input disturbance parameters; wherein, the standard disturbance waveform includes one or any combination of sine wave, cosine wave, triangle wave, square wave, step wave, pulse wave and random wave; The disturbance parameters include disturbance amplitude, disturbance frequency, phase, loading duration, number of cycles, loading interval, and waveform combination method; The closed-loop control system generates a composite target load based on a constant static load reference and dynamic disturbance signals, and outputs static load holding sub-commands and dynamic disturbance tracking sub-commands. The static load holding sub-command is sent to the static load servo valve to maintain the stability of the creep reference load in the long term, while the dynamic disturbance tracking sub-command is sent to the high-frequency servo valve to superimpose time-varying disturbance loads on the reference load. At the same time, the closed-loop control system collects the actual total axial composite load fed back by the axial force sensor and performs independent coordinated corrections on the static load control sub-loop and the dynamic load control sub-loop respectively, eliminating pressure coupling interference between the two hydraulic loops and improving the static load pressure stabilization accuracy and dynamic waveform reproduction fidelity.

[0013] A test method for a rock dynamics test apparatus with synchronous superposition of dynamic and static loads includes the following steps: S1. Sample pretreatment and equipment assembly: Grind and level the surface of the rock sample, attach and fix the rock sample strain sensor to the side wall of the rock sample, and complete the signal wiring and debugging; place the treated rock sample coaxially at the center of the lower pressure head of the confining pressure loading mechanism to ensure that the dynamic and static load synchronous loading servo cylinder, axial loading rod, upper pressure head, rock sample, and lower pressure head are coaxially arranged throughout the entire process. S2. Triaxial confining pressure preloading and stabilization: Start the confining pressure source and confining pressure control valve group, inject hydraulic oil into the confining pressure chamber through the confining pressure inlet, apply lateral confining pressure to the rock sample according to the preset loading rate until the target confining pressure value set in the test is reached; and collect confining pressure data in real time through the confining pressure sensor, and perform closed-loop stabilization and regulation by the closed-loop control system to keep the confining pressure value constant, thereby constructing a stable triaxial stress constraint environment for the rock. S3. Axial Static Load Reference Loading and Creep Stabilization: The static load hydraulic circuit is started, and the static load oil source and static load servo valve are controlled to work. Oil is supplied to the static load oil inlet chamber of the dynamic and static load synchronous loading servo cylinder through the static load oil inlet channel inside the parallel manifold, which pushes the composite piston to move axially. The preset axial creep reference static load is applied to the rock sample through the axial loading rod and the upper pressure head. After the target static load is loaded, the pressure is stabilized by the pressure holding valve and the static load energy accumulator to offset the slight leakage and oil pressure drift in the oil circuit. The axial force, axial displacement and rock sample strain data are continuously monitored until the rock sample deformation enters the stable creep stage, and the long-term rheological reference stress is established. S4. Dynamic Disturbance Parameter Setting and Waveform Configuration: Through the built-in disturbance waveform generation module of the closed-loop control system, select the corresponding disturbance waveform type according to the test conditions, input the disturbance parameters, and generate a standard disturbance waveform or an engineering measured disturbance waveform that matches the actual engineering conditions; at this time, the closed-loop control system will linearly superimpose the constant static load command and the dynamic disturbance command to generate a composite load control command and complete the loading program preset. S5. Synchronous Coupling of Dynamic and Static Loads: The dynamic load hydraulic circuit is started, and the dynamic load oil source outputs pressurized oil. After passing through the high and low pressure regulating components, high frequency servo valve, dynamic oil replenishment valve group, and pulsation suppressor, it enters the dynamic load oil inlet chamber through the dynamic load oil inlet channel inside the parallel manifold. The time-varying oil pressure inside the dynamic load oil inlet chamber acts on the composite piston, outputting a dynamic disturbance load. At the same time, the static load hydraulic circuit continuously stabilizes the pressure, and the constant oil pressure in the static load oil inlet chamber continuously acts on the composite piston and outputs a stable creep reference load. Relying on the mechanical coupling characteristics of the composite piston, the reference static load and the dynamic disturbance load complete the axial force superposition on the same piston to generate an axial composite target load. During this process, the oil in the dynamic load return chamber flows back to the dynamic load oil source through the dynamic load return channel of the parallel manifold and the high frequency servo valve, forming an independent closed-loop circulation. S6. When the set loading time, disturbance cycle number, rock sample failure, or any safety termination condition is met (load limit, displacement limit, oil pressure limit, or sensor malfunction, etc.), the axial strain-time curve, circumferential strain-time curve, axial load-time curve, and dynamic disturbance response curve of the rock sample are obtained based on the data recorded by the data acquisition mechanism.

[0014] Preferably, in step S4, when the disturbance waveform is a measured engineering disturbance waveform, the following preprocessing steps are included: Step 1: Raw waveform data screening and extraction: Import the measured raw time-domain vibration data, remove burrs and noise caused by equipment failure, invalid baseline drift segments and abnormal segments with amplitude exceeding limits, extract the effective time history segments that can truly reflect the disturbance process of the surrounding rock, and determine the total loading duration of the disturbance and the start and end time nodes. The second step is baseline zeroing and amplitude normalization: the effective waveform after truncation is corrected to zero the static offset of the waveform; the measured waveform is scaled proportionally according to the maximum amplitude of the disturbance preset in the test, and the voltage acquisition signal is converted into the load amplitude signal that can be executed by the dynamic load hydraulic circuit, and the disturbance peak value is limited to not exceeding the rated dynamic loading output range of the device cylinder. The third step, sampling frequency adaptation and resampling: Match the original sampling frequency of the measured waveform with the response sampling frequency of the closed-loop control system and the high-frequency servo valve. Through interpolation and resampling, the discrete points of the waveform are densified or downsampled to eliminate waveform distortion caused by missing sampling points and ensure that the high-frequency servo valve can output oil pressure in accordance with the waveform timing. Step 4: Waveform smoothing and filtering: A low-pass digital filtering algorithm is used to smooth and reduce noise in the scaled time history curve, filter out high-frequency electromagnetic interference noise, and retain the measured main frequency characteristics of the disturbance and the attenuation evolution trend. Step 5: Segmented loop and loading rule setting: According to the test plan, set the number of times the measured waveform is loaded in a single operation, the resting time between two waveform loading operations, and the multi-level amplitude application scheme. Import the processed measured disturbance waveform file into the disturbance waveform generation module to generate the engineering measured disturbance waveform.

[0015] Preferably, during the dynamic loading process in step S5, the high-pressure accumulator and the low-pressure accumulator work together to dynamically compensate for the instantaneous flow of the oil circuit, absorb high-frequency pressure pulsation, and work with the pulsation suppressor to eliminate hydraulic shock and reduce dynamic waveform distortion. The expression for the axial composite target load is as follows: ; In the formula, for The total axial force output by the superimposed composite piston at all times; For constant axial creep load; It is a time-varying dynamic disturbance load.

[0016] Therefore, the rock dynamics test device and method with synchronous superposition of dynamic and static loads described above have the following beneficial effects: 1. Single-cylinder integrated force coupling structure with high loading coaxiality and reduced coupling error: It abandons the traditional dual-cylinder split series dynamic and static loading scheme, and outputs composite loads by coaxial superposition. It can effectively alleviate the problems of assembly gap of dual piston rod, eccentric loading, and asynchronous timing response that exist in the traditional dual-cylinder split series dynamic and static loading scheme, greatly reduce coupling loading error, ensure that the loading force transmission path is unique, the axial force detection results are true and reliable, and the triaxial loading centering accuracy is high, avoiding the impact of rock sample eccentric damage on the validity of test data; 2. High fidelity of dynamic disturbance waveform output, adaptable to complex measured disturbance conditions in engineering: The dynamic load circuit is equipped with a high-pressure accumulator, a low-pressure accumulator, a dynamic oil replenishment valve group, and a pulsation suppressor. During peak periods, the accumulator provides instantaneous replenishment, and during valley periods, it absorbs excess oil pressure, effectively compensating for insufficient instantaneous oil supply from the high-frequency servo valve and suppressing hydraulic shock oscillations. The closed-loop control system can accurately reproduce measured disturbance waveforms from on-site blasting, earthquakes, etc., after filtering, resampling, and amplitude calibration preprocessing. The waveform distortion rate is low, which can realistically simulate the effects of irregular random disturbances in engineering sites; 3. Dual-loop independent closed-loop control, with precise separation and targeted correction of deviations: The high-frequency composite control system can independently collect the pressure of two oil circuits through static load oil pressure sensors and dynamic load oil pressure sensors, accurately distinguishing whether the load deviation comes from static load reference drift or dynamic waveform distortion, and separately adjusting the static load servo valve and the high-frequency servo valve. The control logic has a high degree of decoupling, and there will be no problem of mutual interference in the adjustment of a single valve group, resulting in stronger load control robustness. 4. Triaxial stress coupling loading, test conditions closely match the actual occurrence environment of deep rock mass: Different confining pressures within the rated range can be established through the confining pressure loading mechanism. Under the triaxial constraint condition of stable lateral confining pressure, dynamic disturbance loads are superimposed on the axial creep reference load, which breaks through the limitations of pure static load triaxial creep test and short-time uniaxial dynamic and static loading test. The test stress conditions are highly consistent with the service stress state of the surrounding rock of deep buried tunnels and mine roadways. 5. Multi-channel synchronous acquisition of all parameters, with stronger data integrity and traceability: Equipped with a complete acquisition mechanism including confining pressure sensor, axial force sensor, dual oil circuit oil pressure sensor, displacement sensor, and rock sample strain sensor, it can simultaneously record all-dimensional parameters such as confining pressure, total composite load, branch oil pressure, axial overall deformation, local creep of the sample, and dynamic strain. It can completely depict the damage evolution law of the rock from initial deformation, stable creep, accelerated creep to disturbance-induced instability and failure, with more sufficient data support. 6. Multi-mode test compatibility and wide equipment versatility: One set of equipment can switch between three test modes: pure triaxial long-term creep test, pure dynamic fatigue disturbance loading test, and triaxial stress dynamic disturbance-rheological coupling test. It can carry out scientific research in multiple directions such as long-term strength determination of rocks, disturbance accelerated creep mechanism, and time-delay dynamic instability, thereby improving the coverage of test functions.

[0017] In summary, this invention superimposes dynamic disturbance loads with custom amplitude, frequency, and waveform onto a stable creep reference static load, enabling rock samples to simultaneously withstand long-term rheological effects and engineering dynamic disturbances under triaxial confining pressure constraints. The test stress conditions are highly consistent with the actual service environment of deep surrounding rock, effectively making up for the shortcomings of existing test equipment that cannot carry out dynamic-static coupled long-term rheological tests.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a rock dynamics test device for synchronous superposition of dynamic and static loads according to the present invention, wherein (a) is a schematic diagram of the overall structure, (b) is an axial sectional view of the servo cylinder for synchronous loading of dynamic and static loads, and (c) is an axial sectional view of the confining pressure loading mechanism. Figure 2This is a schematic diagram of the piping and control system of a rock dynamics test device for synchronous superposition of dynamic and static loads according to the present invention. Figure 3 The following is an example diagram of the three-dimensional time history curves of the processed seismic wave of a rock dynamics test device with synchronous superposition of dynamic and static loads according to the present invention; wherein, (a) is the time history curve of horizontal X-axis acceleration, (b) is the time history curve of horizontal Y-axis acceleration, and (c) is the time history curve of vertical UD-axis acceleration.

[0020] Figure Labels 1. Reaction frame; 2. Dynamic and static load synchronous loading servo cylinder; 21. Static load inlet chamber; 22. Static load inlet port; 23. Compound piston; 24. Static load return port; 25. Static load return chamber; 26. Piston rod; 27. Dynamic load inlet port; 28. Dynamic load inlet chamber; 29. ​​Dynamic load return port; 210. Dynamic load return chamber; 211. Cylinder body; 212. First isolation sleeve; 213. Second isolation sleeve; 3. Confining pressure loading mechanism; 31. Confining pressure chamber; 32. Confining pressure inlet; 33. 34. Lower pressure head; 35. Confining pressure outlet; 36. Upper pressure head; 37. Axial loading rod; 38. Confining pressure control valve assembly; 4. Confining pressure source; 5. Rock sample; 6. Static load hydraulic circuit; 7. Static load oil source; 8. Static load servo valve; 9. Pressure holding valve; 10. Static load accumulator compensator; 11. Dynamic load hydraulic circuit; 12. Dynamic load oil source; 23. High-pressure accumulator; 34. High-frequency servo valve; 45. Low-pressure accumulator; 66. Dynamic oil replenishment valve assembly; 7. Pulse suppressor; 8. Parallel manifold. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the embodiments of the present invention and are not intended to limit the embodiments of the present invention. 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 this application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0022] It should be noted that the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as a process, method, system, product, or server that includes a series of steps or units, not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or device.

[0023] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0024] like Figures 1-3 As shown, a rock dynamics test device for synchronous superposition of static and dynamic loads includes a reaction frame 1 and a confining pressure loading mechanism 3 fixed on the base of the reaction frame 1. A rock sample 4 is held between the upper pressure head 35 and the lower pressure head 33 of the confining pressure loading mechanism 3. The rock sample 4 is wrapped with a rubber sleeve. The upper pressure head 35 is connected to a servo cylinder 2 for synchronous loading of static and dynamic loads installed on the upper crossbeam of the reaction frame 1. The servo cylinder 2 is connected to a static load hydraulic circuit 5 and a dynamic load hydraulic circuit 6, respectively. The confining pressure loading mechanism 3, the servo cylinder 2 for synchronous loading of static and dynamic loads, the static load hydraulic circuit 5 and the dynamic load hydraulic circuit 6 are all electrically connected to a closed-loop control system. The servo cylinder 2 for synchronous loading of static and dynamic loads, the upper pressure head 35, the rock sample 4 and the lower pressure head 33 are arranged coaxially from top to bottom.

[0025] The servo cylinder 2 for synchronous loading of static and dynamic loads includes a cylinder body 211, a composite piston 23 slidably disposed inside the cylinder body 211, and a piston rod 26 connected to the composite piston 23. The piston rod 26 is fixedly connected to the upper pressure head 35 via an axial loading rod 36. The composite piston 23 divides the interior of the cylinder body 211 into an oil inlet chamber and an oil return chamber. The oil inlet chamber is divided into a static load oil inlet chamber 21 and a dynamic load oil inlet chamber 28 by a first isolation sleeve 212 that is sealed outside the piston rod. The oil return chamber is divided into a static load oil return chamber 25 and a dynamic load oil return chamber 210 by a second isolation sleeve 213 that is sealed outside the piston rod. That is, the first isolation sleeve 212 and the second isolation sleeve 213 are separated into a static load oil return chamber 25 and a dynamic load oil return chamber 210. The outer wall of the sleeve 213 is sealed to the inner wall of the cylinder 211. The inner holes of the first and second isolation sleeves are connected to the piston rod. The static load oil inlet chamber 21 is connected to the oil outlet of the static load hydraulic circuit 5 via the static load oil inlet 22 on the cylinder 211. The oil return end of the static load hydraulic circuit 5 is connected to the static load oil return chamber 25 via the static load oil return port 24 on the cylinder 211. The dynamic load oil inlet chamber 28 is connected to the oil outlet of the dynamic load hydraulic circuit 6 via the dynamic load oil inlet 27 on the cylinder 211. The oil return end of the dynamic load hydraulic circuit 6 is connected to the dynamic load oil return chamber 210 via the dynamic load oil return port 29 on the cylinder 211.

[0026] The static load hydraulic circuit 5 includes a static load oil source 51, a static load servo valve 52, a pressure holding valve, and a static load accumulator compensator 54. The static load oil source 51, static load servo valve 52, and pressure holding valve 53 are connected in series along the oil supply direction to form the static load main oil supply pipeline. The static load accumulator compensator 54 is bypassed and connected to the static load main oil supply pipeline downstream of the pressure holding valve 53. The end of the static load main oil supply pipeline is connected to the static load oil inlet 22 through the static load oil inlet channel in the parallel manifold 7, and the static load oil return port 24 is connected sequentially. The oil flows back to the static load oil source 51 through the static load return oil channel in the parallel manifold 7 and the static load servo valve 52; the dynamic load hydraulic circuit 6 includes a dynamic load oil source 61, a high and low pressure regulating component, a high frequency servo valve 63, a dynamic replenishment valve group 65 and a pulsation suppressor 66 connected in sequence. The pulsation suppressor 66 is connected to the dynamic load oil inlet 27 through the dynamic load oil inlet channel in the parallel manifold 7, and the dynamic load oil return port 29 is connected to the dynamic load oil source 61 through the dynamic load return oil channel in the parallel manifold 7 and the high frequency servo valve 63 in sequence.

[0027] The high and low pressure regulating components include a high-pressure accumulator 62 and a low-pressure accumulator 64 connected in parallel, which are used to instantaneously compensate for oil supply and absorb pipeline pressure pulsations during dynamic disturbance loading.

[0028] The confining pressure loading mechanism 3 includes a confining pressure chamber 31, a lower pressure head 33 fixed to the bottom of the confining pressure chamber 31, and an upper pressure head 35 disposed above the lower pressure head 33. The upper pressure head 35 is fixedly connected to the bottom end of an axial loading rod 36, and the axial loading rod 36 is slidably connected to the top end of the confining pressure chamber 31. The confining pressure chamber 31 has a confining pressure inlet 32 ​​and a confining pressure outlet 34. The confining pressure inlet 32 ​​is connected to the outlet end of the confining pressure source 38 via a confining pressure control valve group 37, and the confining pressure outlet 34 is connected to the inlet of the confining pressure source 38. Thus, by adjusting the confining pressure control valve group 37, the confining pressure can be increased, maintained, depressurized, or applied in stages. The confining pressure chamber 31 is a cavity structure with a confining pressure medium chamber inside.

[0029] The invention also includes a data acquisition mechanism, which is electrically connected to the closed-loop control system.

[0030] Data collection agencies include: The confining pressure sensor is used to collect the lateral confining pressure value applied to the rock sample 4 inside the confining pressure chamber 31 in real time, and transmit the confining pressure simulation signal to the closed-loop control system to realize the closed-loop stabilization and control of the confining pressure under triaxial stress.

[0031] An axial force sensor is used to detect the total axial composite load superimposed by the composite piston 23.

[0032] The static load hydraulic pressure sensor and the dynamic load hydraulic pressure sensor are used to collect the real-time hydraulic pressure of the static load hydraulic circuit 5 and the dynamic load hydraulic circuit 6, respectively.

[0033] A displacement sensor is used to collect the axial displacement of the piston rod 26.

[0034] The rock sample strain sensor includes an axial strain measurement component and a circumferential deformation sensor, which are used to monitor the axial and circumferential local creep strain and the dynamic strain evolution data induced by disturbance of the rock sample, respectively.

[0035] The closed-loop control system has a built-in disturbance waveform generation module, which generates standard disturbance waveforms or engineering measured disturbance waveforms based on the input disturbance parameters. The standard disturbance waveforms include one or any combination of sine waves, cosine waves, triangular waves, square waves, step waves, pulse waves, and random waves. The disturbance parameters include disturbance amplitude, disturbance frequency, phase, loading duration, number of cycles, loading interval, and waveform combination mode. The closed-loop control system generates a composite target load based on a constant static load reference and dynamic disturbance signals, and outputs static load holding sub-commands and dynamic disturbance tracking sub-commands. The static load holding sub-command is sent to the static load servo valve 52 to maintain the stability of the creep reference load in the long term, and the dynamic disturbance tracking sub-command is sent to the high-frequency servo valve 63 to superimpose time-varying disturbance loads on the reference load. At the same time, the closed-loop control system collects the actual total axial composite load fed back by the axial force sensor and performs independent coordinated corrections on the static load control sub-loop and the dynamic load control sub-loop, respectively.

[0036] The closed-loop control system has reserved communication interfaces for external monitoring equipment, and the confining pressure chamber 31 has reserved sensor installation positions. It can be expanded to connect to auxiliary testing modules such as acoustic emission monitoring system and digital image correlation (DIC) monitoring equipment according to test requirements. This facilitates the synchronous acquisition of micro-fracture evolution signals inside the rock as needed, and combines macroscopic mechanical deformation data with microscopic damage evolution characteristics, thereby fully revealing the intrinsic mechanism of dynamic disturbance accelerating long-term creep damage of rocks under triaxial stress.

[0037] It should be noted that the above electronic components are all mature products on the market. This embodiment only requires purchasing them and connecting them according to the instruction manual. No changes have been made to their circuit connection structure. Therefore, their circuit connection structure and principle will not be described in detail here.

[0038] A test method for a rock dynamics test apparatus with synchronous superposition of dynamic and static loads includes the following steps: S1. Sample Pretreatment and Equipment Assembly: Select standard rock samples with regular dimensions and no obvious cracks. Grind and level the surface of the rock samples. Attach and fix the rock sample strain sensor to the side wall of the rock sample and complete the signal wiring and debugging. Place the treated rock sample coaxially at the center of the lower pressure head of the confining pressure loading mechanism to ensure that the dynamic and static load synchronous loading servo cylinder, axial loading rod, upper pressure head, rock sample, and lower pressure head are coaxially arranged throughout the entire process, eliminating eccentric loading errors. Check and confirm that the static load hydraulic circuit, dynamic load hydraulic circuit, and confining pressure hydraulic circuit pipelines are properly connected, sealed without leakage, and that the signal transmission of each sensor and the closed-loop control system is normal.

[0039] S2. Triaxial confining pressure preloading and stabilization: Start the confining pressure source and confining pressure control valve group, inject hydraulic oil into the confining pressure chamber through the confining pressure inlet, apply lateral confining pressure to the rock sample according to the preset loading rate until the target confining pressure value set in the test is reached; and collect confining pressure data in real time through the confining pressure sensor, and perform closed-loop stabilization and regulation by the closed-loop control system to keep the confining pressure value constant, thereby constructing a stable triaxial stress constraint environment for the rock.

[0040] S3. Axial Static Load Reference Loading and Creep Stabilization: The static load hydraulic circuit is started, and the static load oil source and static load servo valve are controlled to work. Oil is supplied to the static load oil inlet chamber of the dynamic and static load synchronous loading servo cylinder through the static load oil inlet channel inside the parallel manifold, which drives the composite piston to move axially. The preset axial creep reference static load is applied to the rock sample through the axial loading rod and the upper pressure head. After the target static load is loaded, the pressure is stabilized by the pressure holding valve and the static load energy accumulator to offset the slight leakage and oil pressure drift in the oil circuit, and maintain the axial reference load constant for a long time. The axial force, axial displacement and rock sample strain data are continuously monitored until the rock sample deformation enters the stable creep stage, and the long-term rheological reference stress is established.

[0041] S4. Dynamic Disturbance Parameter Setting and Waveform Configuration: Through the built-in disturbance waveform generation module of the closed-loop control system, select the corresponding disturbance waveform type according to the test conditions, input the disturbance parameters, and generate a standard disturbance waveform or an engineering measured disturbance waveform that matches the actual engineering conditions; at this time, the closed-loop control system will linearly superimpose the constant static load command and the dynamic disturbance command to generate a composite load control command and complete the loading program preset.

[0042] S5. Synchronous Coupling of Dynamic and Static Loads: The dynamic load hydraulic circuit is activated, and the dynamic load oil source outputs pressurized oil. After passing through the high and low pressure regulating components, high-frequency servo valve, dynamic replenishing valve group, and pulsation suppressor (i.e., the high-frequency servo valve adjusts its opening in real time according to the disturbance control signal output by the closed-loop control system, thereby controlling the amplitude, frequency, and variation law of the dynamic load oil pressure to adapt to different disturbance waveforms), the oil enters the dynamic load inlet chamber through the internal dynamic load inlet channel of the parallel manifold. The time-varying oil pressure inside the dynamic load inlet chamber acts on the composite piston, outputting a dynamic disturbance load. Simultaneously, the static load hydraulic circuit continuously stabilizes the pressure, and the constant oil pressure in the static load inlet chamber continuously acts on the composite piston and outputs a stable creep reference load. Relying on the mechanical coupling characteristics of the composite piston, the reference static load and the dynamic disturbance load complete the axial force superposition on the same piston, generating an axial composite target load. During this process, the oil in the dynamic load return chamber flows back to the dynamic load oil source through the dynamic load return channel of the parallel manifold and the high-frequency servo valve, forming an independent closed-loop circulation.

[0043] S6. When the set loading time, disturbance cycle number, rock sample failure, or any safety termination condition is met (load limit, displacement limit, oil pressure limit, or sensor malfunction, etc.), the axial strain-time curve, circumferential strain-time curve, axial load-time curve, and dynamic disturbance response curve of the rock sample are obtained based on the data recorded by the data acquisition mechanism.

[0044] After data acquisition, the dynamic load hydraulic circuit was disconnected, the high-frequency servo valve was closed, and the dynamic disturbance load output was stopped. Only the static load hydraulic circuit was kept running to maintain a small pressure. After the instantaneous deformation induced by the rock sample disturbance tended to stabilize, the static load servo valve was slowly depressurized to gradually remove the axial creep reference static load, and the axial composite target load was gradually reduced to zero. After the axial load was completely unloaded, the confining pressure loading mechanism was depressurized at a slow rate consistent with the loading rate. After the confining pressure returned to normal pressure, the confining pressure source and confining pressure control valve group were closed. The closed-loop control system completely saved the confining pressure, axial composite load, oil pressure of the two oil circuits, axial displacement, and rock sample surface strain data collected throughout the entire test. If an acoustic emission monitoring module is added in the early stage, the acoustic emission time sequence signal data of micro-fractures inside the rock is archived simultaneously; then the pressure transmission medium inside the confining chamber is discharged, the axial loading rod and the upper pressure head are disassembled, the damaged rock sample is taken out, the shearing, splitting and other failure modes of the sample are observed and recorded and the image data is preserved; the residual pressure of the dynamic and static load hydraulic circuit and the confining pressure hydraulic circuit is completely released, the sealing status of the parallel manifold and the dynamic and static integrated servo cylinder is checked, the debris and oil stains inside the confining chamber are cleaned, the composite piston and piston rod are reset to the initial zero position, and finally, each hydraulic oil source, closed-loop control system and data acquisition equipment are shut off in sequence to complete the entire process of a single dynamic disturbance-long-term rheological coupling triaxial test.

[0045] Meanwhile, according to the needs of experimental research, steps S2 to S6 can be repeated to change different rock samples, adjust the confining pressure level, creep reference stress level, and waveform, amplitude, and frequency parameters of dynamic disturbance, and carry out multiple sets of comparative tests to systematically reveal the influence of dynamic disturbance on the long-term creep rate, long-term strength, and time-effect instability failure mechanism of rock under triaxial stress conditions.

[0046] The above steps enable the synchronous loading of a preset time-varying dynamic disturbance load onto the rock sample while maintaining the axial creep reference static load and the triaxial confining pressure, thereby achieving synchronous coupling loading of long-term rheology and dynamic disturbance.

[0047] In step S4, when the disturbance waveform is a measured disturbance waveform from an engineering facility, the following preprocessing steps are included: Step 1: Raw waveform data screening and extraction: Import the raw time-domain vibration data measured in the field, such as blasting, mechanical vibration, and seismic monitoring. Remove the noise, invalid baseline drift segments and abnormal segments with excessive amplitude caused by the failure of the acquisition equipment. Extract the effective time history segments that can truly reflect the disturbance process of the surrounding rock and determine the total loading duration and start and end time nodes of the disturbance.

[0048] In this embodiment, the original waveform can be an acceleration waveform, a velocity waveform, or a displacement waveform.

[0049] The second step is baseline zeroing and amplitude normalization: the effective waveform after truncation is corrected to zero the static offset of the waveform; the measured waveform is scaled proportionally according to the maximum amplitude of the disturbance preset in the test, and the voltage acquisition signal is converted into the load amplitude signal that can be executed by the dynamic load hydraulic circuit, and the disturbance peak value is limited to not exceeding the rated dynamic loading output range of the device cylinder.

[0050] The third step is sampling frequency adaptation and resampling: The original sampling frequency of the measured waveform is matched with the response sampling frequency of the closed-loop control system and the high-frequency servo valve. The waveform discrete points are densified or downsampled by interpolation resampling to eliminate waveform distortion caused by missing sampling points and ensure that the high-frequency servo valve can output oil pressure in accordance with the waveform timing.

[0051] Step 4: Waveform smoothing and filtering: The scaled time history curve is smoothed and denoised using a low-pass digital filtering algorithm to filter out high-frequency electromagnetic interference noise, retain the main frequency characteristics and attenuation evolution trend of the measured disturbance, avoid the hydraulic system from shock oscillation caused by drastic command jumps, and prevent pressure pulsation in the dynamic load circuit from disturbing the static load creep reference load. Step 5: Segmented loop and loading rule setting: According to the test plan, set the number of times the measured waveform is loaded in a single operation, the resting time between two waveform loading operations, and the multi-level amplitude application scheme. Import the processed measured disturbance waveform file into the disturbance waveform generation module to generate the engineering measured disturbance waveform.

[0052] During the dynamic loading process in step S5, the high-pressure accumulator and the low-pressure accumulator work together to dynamically compensate for the instantaneous flow of the oil circuit, absorb high-frequency pressure pulsation, and work with the pulsation suppressor to eliminate hydraulic shock and reduce dynamic waveform distortion. The expression for the axial composite target load is as follows: ; In the formula, for The total axial force output by the superimposed composite piston at all times; For constant axial creep load; It is a time-varying dynamic disturbance load.

[0053] Throughout the experiment, the closed-loop control system synchronously collects data from various sensors. It monitors triaxial confining pressure stability in real time using a confining pressure sensor, collects the total static and dynamic load using an axial force sensor, and determines the static load reference component and dynamic disturbance component using static and dynamic load control commands and two hydraulic pressure feedback signals. Alternatively, it obtains the static load reference component and dynamic disturbance component by performing frequency band separation on the total load signal. The static and dynamic hydraulic pressure sensors independently monitor the hydraulic pressure status of the two hydraulic circuits, and the displacement sensor and rock sample strain sensor synchronously collect data on the overall deformation and local dynamic and creep strain evolution of the rock sample. Based on the hydraulic pressure and load feedback signals, the control system independently adjusts the static load servo valve and the high-frequency servo valve to avoid pressure crosstalk between the static and dynamic circuits and ensure the accuracy of the experimental loading. In this embodiment, the perturbation waveform, amplitude, and frequency parameters can be adjusted in real time according to the requirements of the test scheme to carry out rock rheological coupling tests under different perturbation conditions and continuously observe the mechanical response and damage evolution law of the rock sample from stable creep to accelerated creep and finally to unstable failure. After the test is completed or the rock sample is completely destroyed, the dynamic load hydraulic circuit is shut off first to stop the dynamic disturbance loading; after the rock sample creep deformation stabilizes, the axial static load and lateral confining pressure are slowly unloaded, and each hydraulic oil source is shut off in sequence; the hydraulic oil inside the confining pressure chamber is drained, the upper pressure head and axial loading rod are disassembled, the destroyed rock sample is taken out, all test data are saved, and each component is reset to its initial state to complete the single test procedure.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A rock dynamics test apparatus for synchronous superposition of static and dynamic loads, comprising a reaction frame and a confining pressure loading mechanism fixed on a base of the reaction frame, wherein a rock sample is held between the upper and lower pressure heads of the confining pressure loading mechanism, characterized in that: The upper pressure head is connected to the dynamic and static load synchronous loading servo cylinder installed on the upper crossbeam of the reaction frame. The dynamic and static load synchronous loading servo cylinder is connected to the static load hydraulic circuit and the dynamic load hydraulic circuit respectively. The confining pressure loading mechanism, the dynamic and static load synchronous loading servo cylinder, the static load hydraulic circuit and the dynamic load hydraulic circuit are all electrically connected to the closed-loop control system. The servo cylinder for synchronous loading of dynamic and static loads, the upper pressure head, the rock sample, and the lower pressure head are arranged coaxially from top to bottom.

2. The rock dynamics test device for synchronous superposition of dynamic and static loads according to claim 1, characterized in that: The dynamic and static load synchronous loading servo cylinder includes a cylinder body, a composite piston that is slidably disposed inside the cylinder body, and a piston rod connected to the composite piston. The piston rod is fixedly connected to the upper pressure head via an axial loading rod. The compound piston divides the cylinder interior into an oil inlet chamber and an oil return chamber. The oil inlet chamber is divided into a static load oil inlet chamber and a dynamic load oil inlet chamber by a first isolation sleeve that is sealed outside the piston rod. The oil return chamber is divided into a static load oil return chamber and a dynamic load oil return chamber by a second isolation sleeve that is sealed outside the piston rod. The static load oil inlet chamber is connected to the oil outlet of the static load hydraulic circuit via the static load oil inlet port opened on the cylinder body, and the oil return end of the static load hydraulic circuit is connected to the static load oil return chamber via the static load oil return port opened on the cylinder body. The dynamic load oil inlet chamber is connected to the oil outlet of the dynamic load hydraulic circuit via the dynamic load oil inlet port opened on the cylinder body, and the oil return end of the dynamic load hydraulic circuit is connected to the dynamic load oil return chamber via the dynamic load oil return port opened on the cylinder body.

3. The rock dynamics test device for synchronous superposition of dynamic and static loads according to claim 2, characterized in that: The static load hydraulic circuit includes a static load oil source, a static load servo valve, a pressure holding valve, and a static load accumulator compensator. The static load oil source, static load servo valve, and pressure holding valve are connected in series along the oil supply direction to form the static load main oil supply pipeline. The static load accumulator compensator is bypassed and connected to the static load main oil supply pipeline downstream of the pressure holding valve. The end of the static load main oil supply pipeline is connected to the static load inlet through the static load inlet channel in the parallel manifold. The static load return port flows back to the static load oil source through the static load return channel in the parallel manifold and the static load servo valve. The dynamic load hydraulic circuit includes a dynamic load oil source, a high and low pressure regulating component, a high frequency servo valve, a dynamic replenishing valve group, and a pulsation suppressor connected in sequence. The pulsation suppressor is connected to the dynamic load oil inlet through the dynamic load oil inlet channel in the parallel manifold, and the dynamic load oil return port is connected to the dynamic load oil source in sequence through the dynamic load oil return channel in the parallel manifold and the high frequency servo valve.

4. The rock dynamics test device for synchronous superposition of dynamic and static loads according to claim 3, characterized in that: The high and low pressure regulating components include a high-pressure accumulator and a low-pressure accumulator connected in parallel, which are used to instantaneously compensate for oil supply and absorb pipeline pressure pulsations during dynamic disturbance loading.

5. A rock dynamics test device for synchronous superposition of dynamic and static loads according to claim 4, characterized in that: The confining pressure loading mechanism includes a confining pressure chamber, a lower pressure head fixed to the bottom of the confining pressure chamber, and an upper pressure head disposed above the lower pressure head. The upper pressure head is fixedly connected to the bottom of the axial loading rod, and the axial loading rod is slidably connected to the top of the confining pressure chamber. The confining pressure chamber is equipped with a confining pressure inlet and a confining pressure outlet. The confining pressure inlet is connected to the outlet end of the confining pressure source via a confining pressure control valve assembly, and the confining pressure outlet is connected to the inlet of the confining pressure source.

6. The rock dynamics test device for synchronous superposition of dynamic and static loads according to claim 5, characterized in that: It also includes a data acquisition mechanism, which is electrically connected to the closed-loop control system; Data collection agencies include: The confining pressure sensor is used to collect the lateral confining pressure value applied to the rock sample inside the confining pressure chamber in real time and transmit the confining pressure simulation signal to the closed-loop control system. An axial force sensor is used to detect the total axial composite load output by the superimposed composite pistons. Static load hydraulic pressure sensor and dynamic load hydraulic pressure sensor are used to collect the real-time hydraulic pressure of static load hydraulic circuit and dynamic load hydraulic circuit respectively; Displacement sensor, used to collect the axial displacement of piston rod; The rock sample strain sensor includes an axial strain measurement component and a circumferential deformation sensor, which are used to monitor the axial and circumferential local creep strain and the dynamic strain evolution data induced by disturbance of the rock sample, respectively.

7. A rock dynamics testing device for synchronous superposition of dynamic and static loads according to claim 6, characterized in that: The closed-loop control system has a built-in disturbance waveform generation module, which is used to generate standard disturbance waveforms or measured disturbance waveforms based on the input disturbance parameters. The standard disturbance waveforms include one or any combination of sine waves, cosine waves, triangular waves, square waves, step waves, pulse waves, and random waves. The disturbance parameters include disturbance amplitude, disturbance frequency, phase, loading duration, number of cycles, loading interval, and waveform combination method; The closed-loop control system generates a composite target load based on a constant static load reference and dynamic disturbance signals, and outputs static load holding sub-commands and dynamic disturbance tracking sub-commands. The static load holding sub-command is sent to the static load servo valve to maintain the stability of the creep reference load in the long term, and the dynamic disturbance tracking sub-command is sent to the high-frequency servo valve to superimpose time-varying disturbance loads on the reference load. At the same time, the closed-loop control system collects the actual total axial composite load fed back by the axial force sensor and performs independent coordinated corrections on the static load control sub-loop and the dynamic load control sub-loop respectively.

8. The test method of a rock dynamics test device with synchronous superposition of dynamic and static loads as described in claim 7, characterized in that: Includes the following steps: S1. Sample pretreatment and equipment assembly: Grind and level the surface of the rock sample, attach and fix the rock sample strain sensor to the side wall of the rock sample, and complete the signal wiring and debugging; place the treated rock sample coaxially at the center of the lower pressure head of the confining pressure loading mechanism to ensure that the dynamic and static load synchronous loading servo cylinder, axial loading rod, upper pressure head, rock sample, and lower pressure head are coaxially arranged throughout the entire process. S2. Triaxial confining pressure preloading and stabilization: Start the confining pressure source and confining pressure control valve group, inject hydraulic oil into the confining pressure chamber through the confining pressure inlet, apply lateral confining pressure to the rock sample according to the preset loading rate until the target confining pressure value set in the test is reached; and collect confining pressure data in real time through the confining pressure sensor, and perform closed-loop stabilization and regulation by the closed-loop control system to keep the confining pressure value constant, thereby constructing a stable triaxial stress constraint environment for the rock. S3. Axial Static Load Reference Loading and Creep Stabilization: The static load hydraulic circuit is started, and the static load oil source and static load servo valve are controlled to work. Oil is supplied to the static load oil inlet chamber of the dynamic and static load synchronous loading servo cylinder through the static load oil inlet channel inside the parallel manifold, which pushes the composite piston to move axially. The preset axial creep reference static load is applied to the rock sample through the axial loading rod and the upper pressure head. After the target static load is loaded, the pressure is stabilized by the pressure holding valve and the static load energy accumulator to offset the slight leakage and oil pressure drift in the oil circuit. The axial force, axial displacement and rock sample strain data are continuously monitored until the rock sample deformation enters the stable creep stage, and the long-term rheological reference stress is established. S4. Dynamic Disturbance Parameter Setting and Waveform Configuration: Through the built-in disturbance waveform generation module of the closed-loop control system, select the corresponding disturbance waveform type according to the test conditions, input the disturbance parameters, and generate a standard disturbance waveform or an engineering measured disturbance waveform that matches the actual engineering conditions; at this time, the closed-loop control system will linearly superimpose the constant static load command and the dynamic disturbance command to generate a composite load control command and complete the loading program preset. S5. Synchronous Coupling of Dynamic and Static Loads: The dynamic load hydraulic circuit is started, and the dynamic load oil source outputs pressurized oil. After passing through the high and low pressure regulating components, high frequency servo valve, dynamic oil replenishment valve group, and pulsation suppressor, it enters the dynamic load oil inlet chamber through the dynamic load oil inlet channel inside the parallel manifold. The time-varying oil pressure inside the dynamic load oil inlet chamber acts on the composite piston, outputting a dynamic disturbance load. At the same time, the static load hydraulic circuit continuously stabilizes the pressure, and the constant oil pressure in the static load oil inlet chamber continuously acts on the composite piston and outputs a stable creep reference load. Relying on the mechanical coupling characteristics of the composite piston, the reference static load and the dynamic disturbance load complete the axial force superposition on the same piston to generate an axial composite target load. During this process, the oil in the dynamic load return chamber flows back to the dynamic load oil source through the dynamic load return channel of the parallel manifold and the high frequency servo valve, forming an independent closed-loop circulation. S6. When the set loading time, disturbance cycle number, rock sample failure, or any safety termination condition is met, the axial strain-time curve, circumferential strain-time curve, axial load-time curve, and dynamic disturbance response curve of the rock sample are obtained based on the data recorded by the data acquisition agency.

9. The test method of a rock dynamics test device with synchronous superposition of dynamic and static loads according to claim 8, characterized in that: In step S4, when the disturbance waveform is a measured disturbance waveform from an engineering facility, the following preprocessing steps are included: Step 1: Raw waveform data screening and extraction: Import the measured raw time-domain vibration data, remove burrs and noise caused by equipment failure, invalid baseline drift segments and abnormal segments with amplitude exceeding limits, extract the effective time history segments that can truly reflect the disturbance process of the surrounding rock, and determine the total loading duration of the disturbance and the start and end time nodes. The second step is baseline zeroing and amplitude normalization: the effective waveform after truncation is corrected to zero the static offset of the waveform; the measured waveform is scaled proportionally according to the maximum amplitude of the disturbance preset in the test, and the voltage acquisition signal is converted into the load amplitude signal that can be executed by the dynamic load hydraulic circuit, and the disturbance peak value is limited to not exceeding the rated dynamic loading output range of the device cylinder. The third step, sampling frequency adaptation and resampling: Match the original sampling frequency of the measured waveform with the response sampling frequency of the closed-loop control system and the high-frequency servo valve. Through interpolation and resampling, the discrete points of the waveform are densified or downsampled to eliminate waveform distortion caused by missing sampling points and ensure that the high-frequency servo valve can output oil pressure in accordance with the waveform timing. Step 4: Waveform smoothing and filtering: A low-pass digital filtering algorithm is used to smooth and reduce noise in the scaled time history curve, filter out high-frequency electromagnetic interference noise, and retain the measured main frequency characteristics of the disturbance and the attenuation evolution trend. Step 5: Segmented loop and loading rule setting: According to the test plan, set the number of times the measured waveform is loaded in a single operation, the resting time between two waveform loading operations, and the multi-level amplitude application scheme. Import the processed measured disturbance waveform file into the disturbance waveform generation module to generate the engineering measured disturbance waveform.

10. The test method of a rock dynamics test device with synchronous superposition of dynamic and static loads according to claim 9, characterized in that: During the dynamic loading process in step S5, the high-pressure accumulator and the low-pressure accumulator work together to dynamically compensate for the instantaneous flow of the oil circuit, absorb high-frequency pressure pulsation, and work with the pulsation suppressor to eliminate hydraulic shock and reduce dynamic waveform distortion. The expression for the axial composite target load is as follows: ； In the formula, for The total axial force output by the superimposed composite piston at all times; For constant axial creep load; It is a time-varying dynamic disturbance load.

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