Steady-state seismic source excitation device

Abstract

The utility model provides a steady-state seismic source excitation device, which comprises a steady-state impact hammer, an impact hammer rod and a base plate, the steady-state impact hammer is used for continuously exciting a seismic source, the output end of the steady-state impact hammer is provided with a clamping part, and the clamping part clamps and fixes the impact hammer rod; the end, away from the clamping part, of the impact hammer rod is fixedly connected with a base plate, and the base plate is used for being fixed to the surface of a rock mass. The device can achieve the stable and continuous excitation of the seismic source, guarantees the frequency band width of the seismic wave excited by the seismic source, and guarantees the intensity of the seismic wave within the effective frequency band range of the seismic source.

Description

Technical Field

[0001] This utility model relates to the field of rock exploration technology, and in particular to a steady-state seismic source excitation device. Background Technology

[0002] In the excavation of underground tunnels in mines, and the construction of underground tunnels in transportation, water conservancy, hydropower, and even national defense projects, it is urgent to understand the adverse geological structures of the surrounding rock or walls to ensure the avoidance of potential dangers and the healthy and stable operation of the project. Seismic wave field micro-motion monitoring is an effective technical means that measures and analyzes the spectral characteristics of seismic waves generated by natural or human activities on the Earth's surface, especially Rayleigh surface waves or shear waves, to understand the mechanical properties of the near-surface medium. However, in the environment of tunnel or roadway construction, the seismic wave fields generated by production operations are random, making it difficult to identify vibration characteristics truly related to the properties of the surrounding rock. Utilizing artificially generated strong near-surface seismic waves and conducting micro-motion monitoring of the rock surface during the excitation period can not only improve the signal-to-noise ratio of single-point vibration signals but also provide a unified background for lateral comparison of vibration signals from different measuring points, resulting in more reliable analysis results and more efficient detection and analysis.

[0003] In the existing technology, the device is generally a seismic source excitation device that performs a single excitation operation. The corresponding seismic acquisition method is to excite once and acquire once, and perform continuous operations in multiple times. This is called a transient source. It is necessary to start acquiring vibration signals at the initial moment of a single source excitation, and the initial moment of source excitation needs to be considered.

[0004] Utility model patent CN216718716U discloses an artificial seismic exploration source activation device, including a frame, a hammer, a support frame, an activation mechanism, and a drive mechanism. The frame is a vertically continuous frame structure, with a support frame on the upper part. The drive mechanism and the activation mechanism are mounted on the support frame. The drive mechanism is connected to the activation mechanism, and the activation mechanism is connected to the hammer. The activation mechanism includes a movable plate and a chain. The hammer is pulled up to a certain height by the chain and then automatically falls, completing one artificial seismic activation. The activation of the artificial seismic event is achieved through the hammer's own weight. Signal acquisition needs to begin at the initial moment of each artificial seismic activation, and the initial moment of source activation must be considered. Utility Model Content

[0005] The purpose of this invention is to overcome the deficiencies in the existing technology and provide a steady-state seismic source excitation device that ensures the bandwidth of the seismic waves excited by the seismic source and the intensity of the seismic waves within the effective frequency band of the excitation source.

[0006] To achieve the above objectives, this utility model provides a steady-state vibration source excitation device, including a steady-state impact hammer, an impact hammer rod, a pad, and a support assembly;

[0007] The steady-state impact hammer is used to continuously excite the vibration source. The output end of the steady-state impact hammer is provided with a clamping part, which clamps and fixes the impact hammer rod.

[0008] The end of the impact hammer rod away from the clamping part is connected to the pad plate, which is used to fix it on the rock surface. One end of the support assembly is connected to the steady-state impact hammer, and the other end is connected to the pad plate or the rock surface to fix the steady-state impact hammer.

[0009] This invention involves drilling multiple installation holes on a relatively solid and stable rock surface to fix a pad to the rock surface; fixing one end of the impact hammer rod to the pad and the other end to the clamping part; using a support assembly to fix the steady-state impact hammer to the pad or the rock surface, ensuring that the steady-state impact hammer is perpendicular to the plane of the pad; turning on the steady-state impact hammer, the output of the steady-state impact hammer strikes the pad through the impact hammer rod, forming a continuous and stable impact vibration.

[0010] This invention, by setting a steady-state impact hammer, can continuously excite the rock surface with a fixed frequency to generate a seismic source. The stable and continuous excitation of the seismic source possesses both the characteristics of transient pulse excitation, ensuring the bandwidth of the seismic waves generated by the source, and the vibration characteristics of steady-state excitation, ensuring the intensity of the seismic waves within the effective frequency band of the excitation source. This creates favorable conditions for conducting vibration testing and analysis on the rock surface. The seismic source is continuously excited at frequencies ranging from 50 to several hundred Hz, meaning it is excited at least once every 20 ms. During stable and continuous excitation, seismic signals with durations several times or even tens of times longer than the source excitation period are collected and recorded, without needing to consider the initial moment of source excitation.

[0011] The pad can be fixed to the surface of rock masses of different shapes and positions. The position of the steady-state seismic source excitation device can be adjusted according to actual needs, and the direction of the seismic source excitation force is free. Fixing the pad to a certain depth within the rock mass surface before exciting the seismic source can improve the excitation efficiency of the seismic source.

[0012] Optionally, the steady-state vibration source excitation device further includes a support assembly, one end of which is connected to the steady-state impact hammer, and the other end is connected to a pad or rock surface for fixing the steady-state impact hammer.

[0013] This invention uses a support assembly to support and fix the steady-state impact hammer, making the connection between the hammer and the rock surface more stable. This concentrates the vibration point and allows for more accurate detection of the seismic waves generated by the hammer. By replacing the support frame with a support assembly, this invention prevents the hammer's vibration from causing the frame to vibrate as well, thus avoiding vibration of the frame affecting the detection of the seismic waves generated by the hammer.

[0014] Optionally, the steady-state impact hammer is set on the bottom surface of the rock mass, and one end of the support component is connected to the steady-state impact hammer and the other end is connected to the pad plate, so that the connection between the steady-state impact hammer and the bottom surface of the rock mass is more stable.

[0015] When the steady-state impact hammer is installed on the rock mass sidewall, one end of the support component is connected to the steady-state impact hammer and the other end is connected to the rock mass sidewall, making the connection between the steady-state impact hammer and the rock mass sidewall more stable.

[0016] Optionally, the support assembly includes a support cable, one end of which is connected to a steady-state impact hammer, and the other end is connected to a pad or rock surface to fix the steady-state impact hammer.

[0017] Multiple support cables are installed. When the steady-state impact hammer is placed on the bottom surface of the rock mass, one end of the support cable is connected to the steady-state impact hammer through a connector on the steady-state impact hammer, and the other end is fixed to the pad plate, making the connection between the steady-state impact hammer and the bottom surface of the rock mass more stable.

[0018] When the steady-state impact hammer is installed on the sidewall of the rock mass, one end of the support cable is connected to the top of the steady-state impact hammer, and the other end is fixed to the sidewall of the rock mass with screws, so that the connection between the steady-state impact hammer and the sidewall of the rock mass is more stable.

[0019] Optionally, the support assembly is provided with shock absorbers.

[0020] This design prevents the support cables from detaching from the pad or rock sidewall due to vibrations caused by the steady-state impact hammer when providing continuous power, ensuring the stability of the support assembly installation. Furthermore, the inclusion of vibration dampers prevents vibrations in the support assembly from affecting the detection of seismic waves generated by the steady-state impact hammer.

[0021] Optionally, the support cable is provided with a hook at one end near the pad, and the pad is provided with a cable hanger that matches and connects to the hook.

[0022] When the steady-state impact hammer is placed on the bottom surface of the rock mass, one end of the support cable is connected to the steady-state impact hammer through a connector set on the steady-state impact hammer, and the other end is equipped with a hook, which is fixed to the cable hanger on the pad plate to realize the limit of the steady-state impact hammer.

[0023] Optionally, the pad is set on the rock surface by expansion screws.

[0024] Optionally, the steady-state impact hammer has a handle at the end away from the clamping part.

[0025] Optionally, the impact hammer rod is threadedly connected to the pad.

[0026] The impact hammer rod has a thread at one end, and the threaded end is screwed into the threaded hole in the center of the pad to achieve a detachable connection between the impact hammer rod and the pad.

[0027] Beneficial effects:

[0028] 1. This utility model includes a steady-state impact hammer, an impact hammer rod, a pad plate, and a support assembly; multiple installation holes are drilled on a relatively solid and stable rock surface to fix the pad plate to the rock surface; one end of the impact hammer rod is fixed to the pad plate, and the other end is fastened to the clamping part; the steady-state impact hammer is fixed to the pad plate or the rock surface using the support assembly to ensure that the steady-state impact hammer is perpendicular to the plane of the pad plate; the steady-state impact hammer is turned on, and the output force of the steady-state impact hammer is hammered to the pad plate through the impact hammer rod, forming a continuous and stable impact vibration.

[0029] This invention, by setting a steady-state impact hammer, can continuously excite the rock surface with a fixed frequency to generate a seismic source. The stable and continuous excitation of the seismic source possesses both the characteristics of transient pulse excitation, ensuring the bandwidth of the seismic waves generated by the source, and the vibration characteristics of steady-state excitation, ensuring the intensity of the seismic waves within the effective frequency band of the excitation source. This creates favorable conditions for conducting vibration testing and analysis on the rock surface. The seismic source is continuously excited at frequencies ranging from 50 to several hundred Hz, meaning it is excited at least once every 20 ms. During stable and continuous excitation, seismic signals with durations several times or even tens of times longer than the source excitation period are collected and recorded, without needing to consider the initial moment of source excitation.

[0030] The pad can be fixed to the surface of rock masses of different shapes and positions. The position of the steady-state seismic source excitation device can be adjusted according to actual needs, and the direction of the seismic source excitation force is free. Fixing the pad to a certain depth within the rock mass surface before exciting the seismic source can improve the excitation efficiency of the seismic source.

[0031] 2. This invention supports and fixes the steady-state impact hammer by setting up a support component, making the connection between the steady-state impact hammer and the bottom surface of the rock mass more stable. This concentrates the vibration point and makes the detection of seismic waves generated by the steady-state impact hammer more accurate. By using a support component instead of a support frame, this invention avoids the vibration of the steady-state impact hammer causing the support frame to vibrate as well, preventing the rock surface in contact with the support frame from vibrating and thus avoiding the support frame vibration affecting the detection of seismic waves generated by the steady-state impact hammer.

[0032] 3. This utility model, by setting up a support component, wherein the steady-state impact hammer is set on the bottom surface of the rock mass, one end of the support component is connected to the steady-state impact hammer and the other end is connected to the pad plate, making the connection between the steady-state impact hammer and the bottom surface of the rock mass more stable; when the steady-state impact hammer is set on the side wall of the rock mass, one end of the support component is connected to the steady-state impact hammer and the other end is connected to the side wall of the rock mass, making the connection between the steady-state impact hammer and the side wall of the rock mass more stable.

[0033] 4. The support assembly of this utility model is equipped with a shock absorber, which can prevent the support assembly from detaching from the pad or rock sidewall due to the vibration of the steady-state impact hammer when providing continuous power, thus ensuring the stable installation of the support cables. Furthermore, the shock absorber can prevent the vibration of the support assembly from affecting the detection of seismic waves generated by the steady-state impact hammer. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0035] Figure 1 This is a structural diagram of the steady-state vibration source excitation device disclosed in this utility model;

[0036] Figure 2 This is a structural diagram of the steady-state vibration source excitation device disclosed in this utility model from another installation direction;

[0037] Figure 3 This is a diagram showing the positions of the excitation point and the vibration sensor in the second embodiment of the steady-state vibration source excitation device disclosed in this utility model.

[0038] Figure 4 This is a schematic diagram of the dispersion curve of the second embodiment of the steady-state vibration source excitation device disclosed in this utility model;

[0039] Figure 5 This is a diagram showing the positions of the excitation point and the vibration sensor in the third embodiment of the steady-state vibration source excitation device disclosed in this utility model.

[0040] Figure 6 This is a slice of the amplitude spectrum of the third embodiment of the steady-state vibration source excitation device disclosed in this utility model.

[0041] Figure label:

[0042] label name label name 1 rock mass 6 pad 2 alleyway 61 screw hole 3 Steady-state impact hammer 62 Cable pendant 31 handle 63 expansion screws 32 plug 7 Support components 4 Clamping part 71 connector 5 Impact hammer rod 72 Support cables 51 Connection part 73 shock absorbers 52 Thread 74 hook up

[0043] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the implementation method and with reference to the accompanying drawings. Detailed Implementation

[0044] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0046] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0047] Example 1:

[0048] See Figure 1 and 2 A steady-state vibration source excitation device according to the first embodiment of the present invention includes a steady-state impact hammer 3, an impact hammer rod 5, and a pad 6.

[0049] The steady-state impact hammer 3 is used to continuously excite the vibration source. The output end of the steady-state impact hammer 3 is provided with a clamping part 4, which clamps and fixes the impact hammer rod 5.

[0050] The end of the impact hammer rod 5 away from the clamping part 4 is fixedly connected to the pad 6, which is used to fix it on the surface of the rock mass 1.

[0051] Specifically, this utility model can be used as a steady-state vibration source excitation device for wall, mine, and tunnel lining inspection, for example, installed in the roadway 2 of a mine or tunnel. Multiple installation holes are drilled on the relatively solid and stable rock mass 1 surface, and a pad 6 is fixed to the surface of the rock mass 1. One end of the impact hammer rod 5 is fixed to the pad 6, and the other end is fastened to the clamping part 4. The steady-state impact hammer 3 is fixed to the pad 6 or the surface of the rock mass 1 using the support assembly 7, ensuring that the steady-state impact hammer 3 is perpendicular to the plane of the pad 6. The steady-state impact hammer 3 is activated, and the output force of the steady-state impact hammer 3 strikes the pad 6 through the impact hammer rod 5, forming a continuous and stable impact vibration.

[0052] The steady-state impact hammer 3 of this invention is fixed to the pad 6 by the impact hammer rod 5. By setting the steady-state impact hammer 3, the surface of the rock mass 1 can be continuously impacted and excited at a fixed frequency to generate a vibration source. The vibration source is stably and continuously excited, which has the characteristics of transient pulse excitation, ensuring the bandwidth of the seismic waves excited by the vibration source, and also has the vibration characteristics of steady-state excitation source, ensuring the intensity of seismic waves within the effective frequency band of the excitation source, thus creating good conditions for vibration testing and analysis of the surface of the rock mass 1.

[0053] In this embodiment, the seismic source is continuously excited at a frequency of 50 to several hundred Hz, that is, it is excited once every 20 ms. During the stable and continuous excitation of the seismic source, seismic signals with a duration of several times or even tens of times longer than the excitation period of the seismic source are collected and recorded, without needing to consider the initial moment of the seismic source excitation.

[0054] The surface of rock mass 1 can be its side or bottom. The pad 6 can be fixed on the surface of rock mass 1 in different shapes and positions. The position of the steady-state vibration source excitation device can be adjusted according to actual needs, and the direction of the vibration source excitation force is free. Fixing the pad 6 to a certain depth within the surface of rock mass 1 to excite the vibration source can improve the excitation efficiency of the vibration source.

[0055] The steady-state impact hammer 3 can be an electric hammer, electric pick, or impact rammer. Modifying a general-purpose electric hammer creates a stable power source; the method is simple and the operation is reliable. It can also be a pneumatic air hammer or jackhammer, equipped with an air pump or air compressor, air valves, etc., to provide continuous impact power. Alternatively, it can be a hydraulic steady-state impact hammer 3, providing continuous impact power through a hydraulic oil pump, oil valves, etc. Materials are readily available, utilizing existing impact products; the source equipment is stable, durable, easy to install, and low-cost. The steady-state impact hammer 3 can also be connected to a frequency converter, allowing for adjustable excitation frequency, creating a variable-frequency impact source. Adjusting the power and hammering frequency can yield sources with different efficiencies.

[0056] The clamping part 4 can be the chuck for impact products such as electric hammers. The impact hammer rod 5 replaces the hammer head or pick head of existing mature electric impact products. Its two ends are detachably connected to the steady-state impact hammer 3 and the pad plate 6, respectively, which facilitates the installation of the impact hammer rod 5.

[0057] See Figure 1 and 2 In some embodiments of this utility model, the steady-state vibration source excitation device further includes a support component 7, one end of which is connected to the steady-state impact hammer 3, and the other end is connected to the pad plate 6 or the surface of the rock mass 1 for fixing the steady-state impact hammer 3.

[0058] This invention uses a support component 7 to support and fix the steady-state impact hammer 3, making the connection between the steady-state impact hammer 3 and the bottom surface of the rock mass 1 more stable. This concentrates the vibration point and makes the detection of seismic waves generated by the steady-state impact hammer 3 more accurate. By using the support component 7 instead of a support frame, this invention avoids the vibration of the steady-state impact hammer 3 causing the support frame to vibrate as well, preventing the rock surface in contact with the support frame from vibrating and thus avoiding the vibration of the support frame affecting the detection of seismic waves generated by the steady-state impact hammer 3.

[0059] See Figure 1 and 2 In some embodiments of this utility model, when the steady-state impact hammer 3 is placed on the bottom surface of the rock mass 1, one end of the support component 7 is connected to the steady-state impact hammer 3 and the other end is connected to the pad plate 6, so that the connection between the steady-state impact hammer 3 and the bottom surface of the rock mass 1 is more stable.

[0060] When the steady-state impact hammer 3 is installed on the side wall of the rock mass 1, one end of the support component 7 is connected to the steady-state impact hammer 3 and the other end is connected to the side wall of the rock mass 1, making the connection between the steady-state impact hammer 3 and the side wall of the rock mass 1 more stable.

[0061] See Figure 1 and 2 In some embodiments of this utility model, the support component 7 includes a support cable 72, one end of which is connected to the steady-state impact hammer 3, and the other end is connected to the pad plate 6 or the surface of the rock mass 1 for fixing the steady-state impact hammer 3.

[0062] In this embodiment, multiple support cables 72 are provided.

[0063] When the steady-state impact hammer 3 is placed on the bottom surface of the rock mass 1, one end of the support cable 72 is connected to the steady-state impact hammer 3 through the connector 71 set on the steady-state impact hammer 3, and the other end is fixed on the pad 6, so that the connection between the steady-state impact hammer 3 and the bottom surface of the rock mass 1 is more stable.

[0064] When the steady-state impact hammer 3 is installed on the side wall of the rock mass 1, one end of the support cable 72 is connected to the top of the steady-state impact hammer 3, and the other end is fixed to the side wall of the rock mass 1 by screws, so that the connection between the steady-state impact hammer 3 and the side wall of the rock mass 1 is more stable.

[0065] See Figure 1 In some embodiments of this utility model, the support assembly 7 is provided with a shock absorber 73.

[0066] In this embodiment, to prevent the support assembly 7 from detaching from the pad 6 or the side wall of the rock mass 1 due to vibration of the steady-state impact hammer 3 when providing continuous power, a damping element 73 is provided to ensure the stable installation of the support assembly 7. The damping element 73 also prevents the vibration of the support assembly 7 from affecting the detection of seismic waves generated by the steady-state impact hammer 3. The damping element 73 is a damping spring.

[0067] See Figure 1 In some embodiments of this utility model, the support cable 72 is provided with a hook 74 at one end near the pad 6, and the pad 6 is provided with a cable hanger 62 that matches and connects with the hook 74.

[0068] When the steady-state impact hammer 3 is placed on the bottom surface of the rock mass 1, one end of the support cable 72 is connected to the steady-state impact hammer 3 through the connector 71 set on the steady-state impact hammer 3, and the other end is provided with a hook 74, which is fixed to the cable hanger 62 of the pad plate 6 through the hook 74 to realize the limit of the steady-state impact hammer 3.

[0069] See Figure 1 and 2 In some embodiments of this utility model, the pad 6 is mounted on the surface of the rock mass 1 using expansion screws 63. The pad 6 is fixed to the surface of the rock mass 1 using the expansion screws 63, thus achieving the fixation of the pad 6.

[0070] See Figure 1 In some embodiments of this utility model, the steady-state impact hammer 3 is provided with a handle 31 at one end away from the clamping part 4. The steady-state impact hammer 3 can be lifted by manually holding the handle 31 or by mechanically connecting it to the handle 31, so as to facilitate the installation and disassembly of the steady-state impact hammer 3.

[0071] See Figure 1 and 2 In some embodiments of this utility model, the impact hammer rod 5 is threadedly connected to the pad plate 6.

[0072] In this embodiment, one end of the impact hammer rod 5 is provided with a thread 52, and one end of the thread 52 is screwed into the screw hole 61 provided in the center of the pad 6 to realize the detachable connection between the impact hammer rod 5 and the pad 6.

[0073] Example 2:

[0074] See Figure 1-4 The method for testing the structural stability of rock mass 1 according to the second embodiment of this utility model includes the following steps:

[0075] S1. Select a vibration point on the surface of rock mass 1 according to the area to be detected, and set the steady-state impact hammer 3 at the vibration point;

[0076] S2. Activate steady-state impact hammer 3 to provide a stable and continuous excitation source;

[0077] S3. Multiple vibration sensors are arranged in the radiation direction of the earthquake source, and the distance between adjacent vibration sensors is S;

[0078] S4. Each of the vibration sensors acquires a vibration record;

[0079] S5. Based on the vibration records obtained from multiple vibration sensors, the stability of the internal geological structure of rock mass 1 is analyzed according to Rayleigh surface wave dispersion.

[0080] See Figure 3 and 4 In some embodiments of this utility model, step S5 specifically includes the following steps:

[0081] S51. Based on the vibration records obtained from multiple vibration sensors, perform frequency domain decomposition using Fourier transform to obtain Rayleigh harmonic signals of different frequencies f(i), wherein the Rayleigh harmonic signals include amplitude and phase.

[0082] S52. Calculate the phase difference in radians Φ(i) between harmonic signals of the same frequency for vibration sensors in the same radiation direction, and obtain the phase velocity V(i) at the corresponding frequency f(i). The formula for calculating the phase velocity V(i) is:

[0083] V(i) = S*2*π*f(i) / Φ(i);

[0084] S53. Calculate the wavelength λ(i) of Rayleigh harmonic signals of different frequencies, λ(i)=V(i) / f(i);

[0085] S54. By obtaining the correlation between wavelength λ(i) and phase velocity V(i), the dispersion curve is obtained. Based on the dispersion curve, the structural state of rock mass 1 at different depths is obtained, thereby determining the structural stability of rock mass 1.

[0086] Rayleigh waves with longer wavelengths are associated with deeper formations, while those with shorter wavelengths are associated with shallower formations. A higher Rayleigh wave phase velocity indicates better shear resistance and greater rock stability in the medium, while a lower wavelength indicates poorer shear resistance and less stable rock.

[0087] Taking the detection of adverse geological structures on the surface of rock mass 1 inside a railway construction tunnel as an example, this provides a guarantee for safe construction and project quality.

[0088] In this embodiment, see Figure 1 Alternatively, the steady-state source excitation device of Example 1 can be used to perform stable and continuous excitation of the source.

[0089] Purchase a steady-state impact hammer 3 with a power of 30J, a hammering frequency of 3000 times / minute (50Hz), and a period of 20ms. Select the hammering function (no rotation required). Based on the dimensions connecting the clamping part 4 and the impact hammer rod 5, manufacture the impact hammer rod 5. The impact hammer rod 5 can be fastened to the clamping part 4, and the other end is made into a cylinder with threads 52. Construct a steel pad 6 with a radius of 30cm and a thickness of 3cm. The pad 6 has a threaded hole in the center that can mate with the impact hammer rod 5. Three expansion screw holes 63 are arranged around the pad 6 in an isosceles triangle shape. Three cable hangers 62 are also arranged around the pad 6 in an isosceles triangle shape. Configure three support cables 72 with hooks 74 and shock-absorbing springs. A connecting piece 71 is fixed in the middle of the steady-state impact hammer 3. The connecting piece 71 can be a belt for hanging the support cables 72. Plug the plug 32 of the steady-state impact hammer 3 into the power socket, and the power socket will start the steady-state impact hammer 3 to operate through the power switch.

[0090] See Figure 1-4 First, select a relatively solid and stable rock surface 1 as the excitation point. The distance between the excitation point and the area to be detected should preferably be more than 20m to avoid the impact of the vibration on the detection of the vibration sensor.

[0091] Multiple mounting holes are drilled at the excitation point, and the pad 6 is fixed to the surface of the rock mass 1 using expansion bolts 63; one end of the impact hammer rod 5 with thread 52 is screwed into the screw hole 61 in the center of the pad 6, and the connecting part 51 at the other end is fastened to the clamping part 4; the steady-state impact hammer 3 is fixed to the cable hanger 62 around the pad 6 using the support cable 72, ensuring that the steady-state impact hammer 3 is perpendicular to the plane of the pad 6; the steady-state impact hammer 3 is turned on, and the inside of the steady-state impact hammer 3 vibrates, which hammers the pad 6 through the impact hammer rod 5, forming a continuous and stable impact vibration with a frequency of 50Hz.

[0092] See Figure 3 The seismic source is continuously excited, and two vibration sensors spaced S apart are deployed along the same radiation direction of the seismic source. The distance between the vibration sensors and the excitation point should ideally be more than 20m to avoid the impact of the shock vibration on the detection of the vibration sensors. The vibration sensors synchronously and independently collect data for a duration of 1 second (50 times the seismic source period of 20ms). Using the two vibration sensors to record the signals, the Rayleigh phase velocity distribution and geological interpretation of the internal geological structure of rock mass 1 can be realized through Rayleigh surface wave dispersion analysis.

[0093] Rayleigh surface wave analysis specifically includes the following steps:

[0094] 1: Based on the vibration records obtained from two sensors, frequency domain decomposition is performed using Fourier transform to obtain Rayleigh harmonic signals of different frequencies f(i), wherein the Rayleigh harmonic signals include amplitude and phase.

[0095] 2. Calculate the phase difference in radians Φ(i) between two vibration sensors for harmonic signals of the same frequency, and obtain the phase velocity V(i) at the corresponding frequency f(i). The formula for calculating the phase velocity V(i) is:

[0096] V(i) = S*2*π*f(i) / Φ(i);

[0097] 3: Calculate the wavelength λ(i) of Rayleigh harmonic signals of different frequencies, λ(i)=V(i) / f(i);

[0098] 4: By analyzing the correlation between wavelength λ(i) and phase velocity V(i), a dispersion curve is obtained. Based on the dispersion curve, the structural state of rock mass 1 at different depths is determined, thereby judging the structural stability of rock mass 1. The recording point of this dispersion curve is the midpoint between the two vibration sensors.

[0099] In theory, longer-wavelength Rayleigh waves are associated with deeper formations, while shorter-wavelength Rayleigh waves are associated with shallower formations. Thus, dispersion curves can be used to illustrate the Rayleigh wave phase velocities at different depths. A higher Rayleigh wave phase velocity indicates better shear resistance and more stable rock, while a lower velocity indicates poorer shear resistance and less stable rock.

[0100] Figure 3 A schematic diagram showing the locations of the excitation point and the vibration sensor; Figure 4 This is a schematic diagram of the Rayleigh wave dispersion curve in this embodiment. The numbers on the horizontal axis and the dashed lines in the figure represent recording points 1 to 10 in this embodiment. The changing curves in the figure represent the phase velocity changes of the Rayleigh wave at different recording points in the medium at different depths. Figure 4 It can be seen that, compared with the Rayleigh wave velocity which is greater than 2m, the phase velocities corresponding to the recording points numbered 5 and 6 are significantly smaller than the phase velocities of other measuring points, which shows a Rayleigh wave low velocity anomaly, proving that there is loose medium in the rock mass below 2m in the vertical direction inside the two recording points 5 and 6.

[0101] By moving two vibration sensors and performing measurements and interpretations using the same method at different locations, the Rayleigh phase velocity distribution within rock mass 1 at different spatial locations can be obtained, thereby enabling the evaluation of the structural stability of rock mass 1 in the area under test. As an improvement, multiple sensors can be deployed simultaneously along the radiation direction of the seismic source, and multi-point calculations and geological interpretations can be performed using the Rayleigh surface wave dispersion analysis method.

[0102] Example 3:

[0103] See Figure 1 , 2 According to the third embodiment of this utility model, a method for testing poor rock mass structure 1 includes the following steps:

[0104] S1. Select an excitation point on the surface of rock mass 1 according to the area to be detected, and set the steady-state impact hammer 3 on the excitation point. The distance L between the excitation point and the boundary of the area to be detected is greater than twice the vertical depth of the surface of the rock mass 1 to be detected.

[0105] S2. Activate steady-state impact hammer 3 to provide a stable and continuous excitation source;

[0106] S3. Move the vibration sensor within the area to be detected;

[0107] S4. Each vibration sensor obtains vibration records at a set grid point one by one;

[0108] S5. Based on the vibration records of the measuring points obtained by multiple vibration sensors, the amplitude spectrum of signals at different frequencies at all measuring points is obtained through spectrum analysis, and then the amplitude spectrum slices corresponding to different frequencies at all measuring points are obtained.

[0109] S6. Analyze the amplitude spectrum slices to determine whether there are adverse geological structures within rock mass 1.

[0110] Taking the advanced detection of adverse geological structures within the surface of rock mass 1 during underground mining tunnel construction as an example, this study aims to avoid encountering fractured zones or water-bearing structures, which could severely impact construction progress and operational safety. The vertical depth to be detected within the surface of rock mass 1 is 15m.

[0111] See Figure 1 Or 2, see Figure 1 Alternatively, the steady-state source excitation device of Example 1 can be used to perform stable and continuous excitation of the source.

[0112] Using a steady-state impact hammer 3 with a power of 60J, a hammering frequency of 3000 times / minute (50Hz frequency, 20ms period), select the hammering function (no rotation required). Based on the dimensions connecting the clamping part 4 and the impact hammer rod 5, manufacture the impact hammer rod 5. The impact hammer rod 5 can be fastened to the clamping part 4, and the other end is made into a cylinder with threads 52. Construct a steel pad 6 with a radius of 30cm and a thickness of 3cm. The pad 6 has a threaded hole in the center that can mate with the impact hammer rod 5. Three expansion screw holes 63 are arranged in an isosceles triangle around the pad 6, and three cable hangers 62 are also arranged in an isosceles triangle around the pad 6. Configure three support cables 72 with hooks 74 and shock-absorbing springs. A connecting piece 71 is fixed in the middle of the steady-state impact hammer 3; the connecting piece 71 can be a belt for attaching the support cables 72. Plug the plug 32 of the steady-state impact hammer 3 into a power socket. The power socket is switched on to start the steady-state impact hammer 3.

[0113] The distance L between the excitation point and the boundary of the area to be detected is greater than twice the vertical depth of the surface of the rock mass 1 to be detected. Therefore, a relatively solid and stable surface of the rock mass 1, which is more than 30m away from the boundary of the area to be detected, is selected as the excitation point. Installation holes are drilled at the excitation point, and the pad 6 is fixed to the surface of the rock mass 1 using expansion screws 63. One end of the impact hammer rod 5 with thread 52 is screwed into the screw hole 61 in the center of the pad 6, and the connecting part 51 at the other end is fastened to the clamping part 4. The steady-state impact hammer 3 is also fixed to the surface of the rock mass 1 around the pad 6 using three support cables 72 with shock-absorbing springs and expansion screws, ensuring that the steady-state impact hammer 3 is perpendicular to the plane of the pad 6. When the power is turned on, the steady-state impact hammer 3 strikes the pad 6 through the head of the impact hammer rod 5, forming a continuous and stable impact vibration.

[0114] The vibration source is continuously excited; vibration sensors are used to obtain vibration records at measuring points with a certain grid size (e.g., 1m*1m) in the area to be detected, with each measuring point recording lasting 2 seconds, which is 100 times the hammer impact period of 20 milliseconds. Through spectral analysis such as Fourier transform and entropy spectrum analysis, the amplitude spectra of signals at different frequencies at all measuring points can be obtained, thus obtaining amplitude spectrum slices corresponding to different frequencies at all measuring points, such as... Figure 6 As shown.

[0115] The amplitude of the amplitude spectrum at different frequencies directly reflects the strength of the resonance of the rock mass structure. The non-dense structure in the rock mass will produce obvious resonance phenomena. Moreover, the short wavelength of the high-frequency signal represents the shallow geological structure information, while the long wavelength of the low-frequency signal represents the deeper geological structure information. Based on this principle, the geological structure state information from shallow to deep within the surface of the tested rock mass can be interpreted. Figure 6 Darker colored areas represent higher amplitudes, while lighter colored areas represent smaller amplitudes. Figure 6 There are local areas with high amplitude, indicating that there is a loose structure on the surface of the rock mass in the local detection area. The lower the frequency corresponding to the high amplitude area, the deeper the loose area is, and vice versa.

[0116] The above are merely preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent structural transformations made based on the inventive concept of this utility model and the contents of this utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of this utility model.

Claims

1. A steady-state vibration source excitation device, characterized in that, Includes a steady-state impact hammer, impact hammer rod, and pad. The steady-state impact hammer is used to continuously excite the vibration source. The output end of the steady-state impact hammer is provided with a clamping part, which clamps and fixes the impact hammer rod. The end of the impact hammer rod away from the clamping part is fixedly connected to a pad, which is used to fix it on the surface of the rock mass.

2. The steady-state vibration source excitation device according to claim 1, characterized in that, The steady-state vibration source excitation device also includes a support assembly, one end of which is connected to the steady-state impact hammer, and the other end is connected to a pad or rock surface to fix the steady-state impact hammer.

3. The steady-state vibration source excitation device according to claim 2, characterized in that, When the steady-state impact hammer is placed on the bottom surface of the rock mass, one end of the support assembly is connected to the steady-state impact hammer, and the other end is connected to the pad plate; When the steady-state impact hammer is installed on the rock mass sidewall, one end of the support assembly is connected to the steady-state impact hammer, and the other end is connected to the rock mass sidewall.

4. The steady-state vibration source excitation device according to claim 2, characterized in that, The support assembly includes a support cable, one end of which is connected to a steady-state impact hammer, and the other end is connected to a pad or rock surface to fix the steady-state impact hammer.

5. The steady-state vibration source excitation device according to claim 4, characterized in that, The support cable is provided with a hook at one end near the pad, and the pad is provided with a cable hanger that matches and connects to the hook.

6. The steady-state vibration source excitation device according to claim 2, characterized in that, The support assembly is equipped with shock absorbers.

7. The steady-state vibration source excitation device according to any one of claims 1-6, characterized in that, The pad is set on the surface of the rock mass by expansion screws.

8. The steady-state vibration source excitation device according to any one of claims 1-6, characterized in that, The steady-state impact hammer has a handle at the end away from the clamping part.

9. The steady-state vibration source excitation device according to any one of claims 1-6, characterized in that, The impact hammer rod is threadedly connected to the pad plate.

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