Steady-state seismic source excitation device and rock mass structure stability and bad structure testing method

Abstract

The invention provides a steady-state seismic source excitation device and a rock mass structural stability and bad structure testing method, the steady-state seismic source excitation device 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. Stable and continuous excitation of the seismic source can be realized, the frequency band width of seismic waves excited by the seismic source is ensured, and the intensity of the seismic waves within the effective frequency band range of the seismic source is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of rock mass exploration, and in particular to a steady-state source excitation device, a rock mass structure stability and a bad structure testing method. Background Art

[0002] In the excavation of underground mine tunnels, transportation, water conservancy and hydropower, and even defense engineering underground tunnel construction, it is urgent to understand the adverse geological structure of the surrounding rock or wall to avoid dangerous hidden dangers and ensure the health and stability of the project. Seismic wave field micro-motion monitoring is an effective technical means. It measures and analyzes seismic waves generated by natural or human activities on the surface, especially the spectrum characteristics of Rayleigh surface waves or shear waves to understand the mechanical properties of near-surface medium structures. However, in the construction environment of tunnels or tunnels, the seismic wave field generated by production operations is random, which makes it difficult to identify the vibration characteristics that are truly related to the surrounding rock properties. Using artificial active excitation of strong near-surface seismic waves, monitoring the rock surface micro-motion during the excitation period can not only improve the signal-to-noise ratio of single-point vibration measurement signals, but also provide a unified background for the lateral comparison of vibration measurement signals at different measurement points, making the analysis results more reliable and the detection and analysis efficient.

[0003] The device in the prior art is generally a source excitation device that operates once. The corresponding seismic acquisition method is to excite once, collect once, and operate continuously in batches. It is called a transient source. It is necessary to start collecting vibration signals at the initial moment of a single source excitation, and the initial moment of source excitation needs to be considered.

[0004] The utility model with the publication number CN216718716U discloses an artificial earthquake exploration source excitation device, including a frame, a hammer, a support frame, an excitation mechanism and a driving mechanism; the frame is a frame structure that penetrates from top to bottom, a support frame is arranged on the upper part of the frame, a driving mechanism and an excitation mechanism are arranged on the support frame, the driving mechanism is connected to the excitation mechanism, and the excitation mechanism is connected to the hammer; the excitation mechanism includes a movable plate and a chain. However, the hammer is automatically dropped after being pulled up to a certain height by the chain, completing the excitation of an artificial earthquake. The excitation of an artificial earthquake is completed by the self-gravity of the hammer, and it is necessary to start collecting signals at the initial moment of a single artificial earthquake excitation, and the initial moment of source excitation needs to be considered. Summary of the invention

[0005] The purpose of the present invention is to solve the defects in the prior art and provide a steady-state source excitation device to achieve stable and continuous excitation of the source, ensure the frequency bandwidth of the seismic waves excited by the source, and ensure the intensity of the seismic waves within the effective frequency band of the excitation source.

[0006] To achieve the above-mentioned object, the present invention provides a steady-state source excitation device, comprising 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 seismic source, and 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;

[0008] One end of the impact hammer rod away from the clamping part is connected to a pad, and the pad is used to be fixed 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 or the rock surface for fixing the steady-state impact hammer.

[0009] The present invention punches a plurality of installation holes on a relatively firm and stable rock surface, fixes a pad on the rock surface; fixes one end of an impact hammer rod on the pad, and fastens the other end with a clamping portion; uses a support assembly to fix the steady-state impact hammer on the pad or the rock surface, ensuring that the steady-state impact hammer is perpendicular to the pad plane; turns on the steady-state impact hammer, and the steady-state impact hammer output hammers the pad through the impact hammer rod, forming a continuous and stable impact vibration.

[0010] The present invention can continuously impact and excite the rock surface with a fixed frequency to generate a seismic source by setting a steady-state impact hammer. The seismic source is stably and continuously excited, and has the characteristics of transient pulse excitation, ensuring the bandwidth of the seismic wave excited by the seismic source, and also has the vibration characteristics of a steady-state excitation seismic source, ensuring the intensity of the seismic wave within the effective frequency band of the excitation source, creating good conditions for vibration testing and analysis on the rock surface. The seismic source is continuously excited, with a frequency of up to 50 to hundreds of Hz, that is, it is excited at least once within 20ms. During the stable and continuous excitation of the seismic source, seismic signals with a duration several times or even dozens of times longer than the source excitation period are collected and recorded, without considering the initial moment of source excitation.

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

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

[0013] The present invention supports and fixes the steady-state impact hammer by arranging a support assembly, so that the connection between the steady-state impact hammer and the bottom surface of the rock mass is more stable, the vibration point can be concentrated, and the detection of the seismic wave generated by the steady-state impact hammer is more accurate. The present invention uses a support assembly instead of a bracket support to avoid the vibration of the steady-state impact hammer and the bracket vibrating together, so that the rock surface contacted by the bracket also vibrates, and the vibration of the bracket is prevented from affecting the detection of the seismic wave generated by the steady-state impact hammer.

[0014] Optionally, the steady-state impact hammer is arranged 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, 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 arranged on the side wall 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 side wall of the rock mass, so that the connection between the steady-state impact hammer and the side wall of the rock mass is more stable.

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

[0017] There are multiple support cables. When the steady-state impact hammer is set 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 fixed on the pad, so that the connection between the steady-state impact hammer and the bottom surface of the rock mass is more stable.

[0018] When the steady-state impact hammer is set on the side wall 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 side wall of the rock mass by screws, so that the connection between the steady-state impact hammer and the side wall of the rock mass is more stable.

[0019] Optionally, a shock absorbing member is provided on the support assembly.

[0020] It can prevent the vibration of the steady-state impact hammer from causing the support cable to come off the pad or the side wall of the rock mass when the steady-state impact hammer provides continuous power, ensuring the stable installation of the support assembly. The provision of the shock-absorbing member can also prevent the vibration of the support assembly from affecting the detection of the seismic waves generated by the steady-state impact hammer.

[0021] Optionally, a hook is provided at one end of the support cable adjacent to the base plate, and a cable hanger matching and connected to the hook is provided on the base plate.

[0022] When the steady-state impact hammer is set on the bottom surface of the rock mass, one end of the support cable is connected to the steady-state impact hammer through a connecting piece set on the steady-state impact hammer, and the other end is provided with a hook, which is fixed to the cable hanger of the pad through the hook to achieve the limiting of the steady-state impact hammer.

[0023] Optionally, the pad is arranged on the rock surface by means of expansion screws.

[0024] Optionally, a handle is provided at one end of the steady-state impact hammer away from the clamping portion.

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

[0026] One end of the impact hammer rod is provided with a thread, and the threaded end is screwed into a screw hole arranged in the center of the backing plate to realize the detachable connection between the impact hammer rod and the backing plate.

[0027] The present invention also provides a rock structure stability testing method, comprising the following steps:

[0028] S1. Select a shock point on the rock surface according to the intended detection area, and set a steady-state impact hammer on the shock point;

[0029] S2, turn on the steady-state impact hammer, a stable and continuous excitation source;

[0030] S3, multiple vibration sensors are arranged in the radiation direction of the earthquake source, and the spacing between adjacent vibration sensors is S;

[0031] S4, each of the vibration sensors obtains a vibration record;

[0032] S5. Vibration records obtained by multiple vibration sensors are used to analyze the stability of the geological structure inside the rock mass based on Rayleigh surface wave dispersion.

[0033] Optionally, step S5 specifically includes the following steps:

[0034] S51, performing frequency domain decomposition using Fourier transform according to vibration records obtained by multiple vibration sensors, and decomposing to obtain Rayleigh wave harmonic signals of different frequencies f(i), wherein the Rayleigh wave harmonic signals include amplitude and phase;

[0035] S52, calculate the phase difference radian value Φ(i) between the harmonic signals of the same frequency of the vibration sensors in the same radiation direction, and obtain the phase velocity V(i) corresponding to the frequency f(i). The calculation formula of the phase velocity V(i) is:

[0036] V(i)=S*2*π*f(i) / Φ(i);

[0037] S53, calculating the wavelength λ(i) of the Rayleigh wave harmonic signals of different frequencies, λ(i)=V(i) / f(i);

[0038] S54. The dispersion curve is obtained through the correlation between the wavelength λ(i) and the phase velocity V(i). The rock structure state at different depths is obtained according to the dispersion curve, so as to judge the stability of the rock structure.

[0039] Rayleigh waves with longer wavelengths are associated with deeper strata, while Rayleigh waves with shorter wavelengths are associated with shallower strata. The greater the Rayleigh wave phase velocity, the better the shear resistance of the medium and the more stable the rock. Conversely, the worse the shear resistance is, the worse the rock stability is.

[0040] The present invention also provides a method for testing rock mass poor structure, comprising the following steps:

[0041] S1. Select an exciting point on the rock surface according to the intended detection area, and set a steady-state impact hammer on the exciting point. The distance L between the exciting point and the boundary of the intended detection area is greater than twice the vertical depth of the rock surface to be detected;

[0042] S2, turn on the steady-state impact hammer, a stable and continuous excitation source;

[0043] S3, moving the vibration sensor in the intended detection area;

[0044] S4, the vibration sensor obtains the vibration records of the measuring points of the set grid degree point by point;

[0045] S5. According to the vibration records of the measuring points obtained by the vibration sensor, the amplitude spectra of the signals of different frequencies at all the measuring points are obtained by spectrum analysis, and then the amplitude spectrum slices corresponding to the different frequencies of all the measuring points are obtained;

[0046] S6. Analyze the amplitude spectrum slices to determine whether there are adverse geological structures in the rock mass.

[0047] Beneficial effects:

[0048] 1. The present invention comprises a steady-state impact hammer, an impact hammer rod, a pad and a support assembly; a plurality of mounting holes are punched on a relatively firm and stable rock surface, and the pad is fixed on the rock surface; one end of the impact hammer rod is fixed on the pad, and the other end is fastened with a clamping portion; the steady-state impact hammer is fixed on the pad or the rock surface by using a support assembly to ensure that the steady-state impact hammer is perpendicular to the pad plane; the steady-state impact hammer is turned on, and the steady-state impact hammer output hammers the pad through the impact hammer rod to form a continuous and stable impact vibration.

[0049] The present invention can continuously impact and excite the rock surface with a fixed frequency to generate a seismic source by setting a steady-state impact hammer. The seismic source is stably and continuously excited, and has the characteristics of transient pulse excitation, ensuring the bandwidth of the seismic wave excited by the seismic source, and also has the vibration characteristics of a steady-state excitation seismic source, ensuring the intensity of the seismic wave within the effective frequency band of the excitation source, creating good conditions for vibration testing and analysis on the rock surface. The seismic source is continuously excited, with a frequency of up to 50 to hundreds of Hz, that is, it is excited at least once within 20ms. During the stable and continuous excitation of the seismic source, seismic signals with a duration several times or even dozens of times longer than the source excitation period are collected and recorded, without considering the initial moment of source excitation.

[0050] The pad can be fixed on the surface of rock masses of different shapes and positions. The position of the steady-state source excitation device can be adjusted according to actual needs, and the direction of the source excitation output is free. Fixing the pad at a certain depth inside the rock surface and then exciting the source can improve the source excitation efficiency.

[0051] 2. The present invention supports and fixes the steady-state impact hammer by providing a support assembly, so that the connection between the steady-state impact hammer and the bottom surface of the rock mass is more stable, the vibration points can be concentrated, and the detection of the seismic waves generated by the steady-state impact hammer is more accurate. The present invention uses a support assembly instead of a bracket support to avoid the vibration of the steady-state impact hammer causing the bracket to vibrate together, causing the rock surface contacted by the bracket to vibrate, and avoiding the vibration of the bracket affecting the detection of the seismic waves generated by the steady-state impact hammer.

[0052] 3. The present invention arranges a support assembly, wherein the steady-state impact hammer is arranged 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, so that the connection between the steady-state impact hammer and the bottom surface of the rock mass is more stable; when the steady-state impact hammer is arranged on the side wall 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 side wall of the rock mass, so that the connection between the steady-state impact hammer and the side wall of the rock mass is more stable.

[0053] 4. The support assembly of the present invention is provided with a shock absorber, which can prevent the vibration of the steady-state impact hammer from causing the support assembly to fall out of the pad or the side wall of the rock mass when the steady-state impact hammer provides continuous power, thereby ensuring the stable installation of the support cable. The provision of the shock absorber can also prevent the vibration of the support assembly from affecting the detection of the seismic waves generated by the steady-state impact hammer. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0055] Figure 1 It is a structural diagram of the steady-state source excitation device disclosed in the present invention;

[0056] Figure 2 It is a structural diagram of another installation direction of the steady-state seismic source excitation device disclosed in the present invention;

[0057] Figure 3 A position diagram of the excitation point and the vibration sensor in the rock structure stability testing method disclosed in the present invention;

[0058] Figure 4 It is a schematic diagram of a dispersion curve of the rock structure stability testing method disclosed in the present invention;

[0059] Figure 5 A position diagram of the excitation point and the vibration sensor in the rock mass bad structure testing method disclosed in the present invention;

[0060] Figure 6It is an amplitude spectrum slice diagram of the rock mass bad structure testing method disclosed in the present invention.

[0061] Reference numerals:

[0062]

[0063]

[0064] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with the embodiments with reference to the accompanying drawings. DETAILED DESCRIPTION

[0065] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0066] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific content of the technical solution.

[0067] In the description of the present invention, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0068] Embodiment 1:

[0069] See also Figure 1 and 2 , a steady-state seismic source excitation device according to the first embodiment of the present invention comprises a steady-state impact hammer 3, an impact hammer rod 5 and a pad 6;

[0070] The steady-state impact hammer 3 is used to continuously excite the seismic source, and a clamping portion 4 is provided at the output end of the steady-state impact hammer 3, and the clamping portion clamps and fixes the impact hammer rod 5;

[0071] One end of the impact hammer rod 5 away from the clamping portion 4 is fixedly connected to a backing plate 6 , and the backing plate 6 is used to be fixed on the surface of the rock mass 1 .

[0072] Specifically, the present invention can be used as a steady-state source excitation device for wall, mine, and tunnel lining detection, for example, it can be set in the tunnel 2 of a mine or tunnel. A plurality of installation holes are punched on the surface of a relatively solid and stable rock mass 1, and a pad 6 is fixed on the surface of the rock mass 1; one end of the impact hammer rod 5 is fixed on the pad 6, and the other end is fastened with the clamping part 4; the steady-state impact hammer 3 is fixed on the pad 6 or the surface of the rock mass 1 by 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 turned on, and the output of the steady-state impact hammer 3 hammers the pad 6 through the impact hammer rod 5, forming a continuous and stable impact vibration.

[0073] The steady-state impact hammer 3 of the present invention is fixed on the pad 6 through the impact hammer rod 5. By setting the steady-state impact hammer 3, it can continuously impact and excite the surface of the rock mass 1 at a fixed frequency to generate a seismic source. The seismic source is stably and continuously excited, and has the characteristics of transient pulse excitation, ensuring the frequency bandwidth of the seismic wave excited by the seismic source, and also has the vibration characteristics of a steady-state excitation seismic source, ensuring the intensity of the seismic wave within the effective frequency band of the excitation source, creating good conditions for conducting vibration testing and analysis on the surface of the rock mass 1.

[0074] In this embodiment, the seismic source is continuously excited with a frequency as high as 50 to hundreds of Hz, that is, it is excited at least once every 20 ms. During the stable and continuous excitation of the seismic source, seismic signals with a duration several times or even dozens of times longer than the seismic source excitation period are collected and recorded, without considering the initial moment of the seismic source excitation.

[0075] The surface of the rock mass 1 can be the side or bottom of the rock mass 1, and the pad 6 can be fixed on the surface of the rock mass 1 in different shapes and positions. The position of the steady-state source excitation device can be adjusted according to actual needs, and the direction of the source excitation output force is free. After the pad 6 is fixed at a certain depth inside the surface of the rock mass 1 and the source is excited, the excitation efficiency of the source can be improved.

[0076] The steady-state impact hammer 3 can be an electric hammer, an electric pick or an impact rammer. The universal electric hammer can be modified to form a stable output source. The method is simple and reliable. It can also be a pneumatic air hammer or a pneumatic pick, equipped with an air pump or an air compressor, an air valve, etc. to provide continuous impact power; it can also be a hydraulic steady-state impact hammer 3, which provides continuous impact power through a hydraulic oil pump, an oil valve, etc., and is easy to obtain materials. It uses existing impact products, and the source equipment has stable performance, is durable, easy to install, and has low cost. The steady-state impact hammer 3 can also be connected to a frequency conversion controller, and the excitation frequency can be adjusted to form a variable frequency impact source. Adjusting the power and hammering frequency can obtain sources with different efficiencies.

[0077] The clamping part 4 can be a chuck of an impact product such as an electric hammer, and the impact hammer rod 5 replaces the hammer head or pick head of an existing mature electric impact product. Its two ends are detachably connected to the steady-state impact hammer 3 and the pad 6 respectively, which is convenient for the installation of the impact hammer rod 5.

[0078] See also Figure 1 and 2 In some embodiments of the present invention, the steady-state seismic source excitation device also includes a support assembly 7, one end of the support assembly 7 is connected to the steady-state impact hammer 3, and the other end is connected to the pad 6 or the surface of the rock mass 1 for fixing the steady-state impact hammer 3.

[0079] The present invention supports and fixes the steady-state impact hammer 3 by providing a support assembly 7, so that the connection between the steady-state impact hammer 3 and the bottom surface of the rock mass 1 is more stable, the vibration point can be concentrated, and the detection of the seismic wave generated by the steady-state impact hammer 3 is more accurate. The present invention uses the support assembly 7 instead of the bracket support to avoid the vibration of the steady-state impact hammer 3 and the vibration of the bracket, so that the rock surface contacted by the bracket also vibrates, and the vibration of the bracket is prevented from affecting the detection of the seismic wave generated by the steady-state impact hammer 3.

[0080] See also Figure 1 and 2 In some embodiments of the present invention, when the steady-state impact hammer 3 is arranged on the bottom surface of the rock mass 1, one end of the support assembly 7 is connected to the steady-state impact hammer 3, and the other end is connected to 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;

[0081] When the steady-state impact hammer 3 is set on the side wall of the rock mass 1, one end of the support assembly 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, so that the connection between the steady-state impact hammer 3 and the side wall of the rock mass 1 is more stable.

[0082] See also Figure 1 and 2 In some embodiments of the present invention, the support assembly 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 6 or the surface of the rock mass 1 for fixing the steady-state impact hammer 3.

[0083] In this embodiment, a plurality of support cables 72 are provided.

[0084] When the steady-state impact hammer 3 is set 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 connecting piece 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.

[0085] When the steady-state impact hammer 3 is set 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.

[0086] See also Figure 1 In some embodiments of the present invention, a shock absorbing member 73 is provided on the supporting assembly 7.

[0087] In this embodiment, in order to prevent the vibration of the steady-state impact hammer 3 from causing the support assembly 7 to fall out of the pad 6 or the side wall of the rock mass 1 when the steady-state impact hammer 3 provides continuous power, a shock absorber 73 is provided to ensure the stable installation of the support assembly 7. The provision of the shock absorber 73 can also prevent the vibration of the support assembly 7 from affecting the detection of the seismic wave formed by the steady-state impact hammer 3. The shock absorber 73 is a shock absorbing spring.

[0088] See also Figure 1 In some embodiments of the present invention, a hook 74 is provided at one end of the support cable 72 adjacent to the pad 6 , and a cable hanger 62 matching and connected to the hook 74 is provided on the pad 6 .

[0089] When the steady-state impact hammer 3 is set 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 a connecting piece 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 6 through the hook 74 to achieve the limiting of the steady-state impact hammer 3.

[0090] See also Figure 1 and 2 In some embodiments of the present invention, the pad 6 is arranged on the surface of the rock mass 1 by means of expansion screws 63. The pad 6 is fixed on the surface of the rock mass 1 by means of the expansion screws 63, so that the pad 6 is fixed.

[0091] See also Figure 1 In some embodiments of the present invention, a handle 31 is provided at one end of the steady-state impact hammer 3 away from the clamping portion 4. The steady-state impact hammer 3 is lifted by manually holding the handle 31 or mechanically connecting the handle 31 to facilitate installation and disassembly of the steady-state impact hammer 3.

[0092] See also Figure 1 and 2 In some embodiments of the present invention, the impact hammer rod 5 is threadedly connected to the backing plate 6.

[0093] In this embodiment, a thread 52 is provided at one end of the impact hammer rod 5, and one end of the thread 52 is screwed into a screw hole 61 provided in the center of the backing plate 6 to achieve a detachable connection between the impact hammer rod 5 and the backing plate 6.

[0094] Embodiment 2:

[0095] See also Figure 1-4 According to the second embodiment of the present invention, the method for testing the structural stability of a rock mass 1 comprises the following steps:

[0096] S1, selecting a shock point on the surface of the rock mass 1 according to the intended detection area, and setting the steady-state impact hammer 3 on the shock point;

[0097] S2, start the steady-state impact hammer 3, stable and continuous excitation source;

[0098] S3, multiple vibration sensors are arranged in the radiation direction of the earthquake source, and the spacing between adjacent vibration sensors is S;

[0099] S4, each of the vibration sensors obtains a vibration record;

[0100] S5. Analyze the stability of the internal geological structure of the rock mass 1 based on the vibration records obtained by multiple vibration sensors and Rayleigh surface wave dispersion.

[0101] See also Figure 3 and 4 In some embodiments of the present invention, step S5 specifically includes the following steps:

[0102] S51, performing frequency domain decomposition using Fourier transform according to vibration records obtained by multiple vibration sensors, and decomposing to obtain Rayleigh wave harmonic signals of different frequencies f(i), wherein the Rayleigh wave harmonic signals include amplitude and phase;

[0103] S52, calculate the phase difference radian value Φ(i) between the harmonic signals of the same frequency of the vibration sensors in the same radiation direction, and obtain the phase velocity V(i) corresponding to the frequency f(i). The calculation formula of the phase velocity V(i) is:

[0104] V(i)=S*2*π*f(i) / Φ(i);

[0105] S53, calculating the wavelength λ(i) of the Rayleigh wave harmonic signals of different frequencies, λ(i)=V(i) / f(i);

[0106] S54. A dispersion curve is obtained through the correlation between the wavelength λ(i) and the phase velocity V(i). The structural state of the rock mass 1 at different depths is obtained according to the dispersion curve, thereby judging the structural stability of the rock mass 1.

[0107] Rayleigh waves with longer wavelengths are associated with deeper strata, while Rayleigh waves with shorter wavelengths are associated with shallower strata. The greater the Rayleigh wave phase velocity, the better the shear resistance of the medium and the more stable the rock. Conversely, the worse the shear resistance is, the worse the rock stability is.

[0108] Taking the detection of adverse geological structures on the surface of rock mass 1 in a railway construction tunnel as an example, it provides guarantees for safe construction and project quality.

[0109] In this embodiment, see Figure 1 Or 2, using the steady-state seismic source excitation device of Example 1 to perform stable and continuous excitation of the seismic source.

[0110] Choose a steady-state impact hammer 3 with a power of 30J, a hammering frequency of 3000 times / minute, that is, a frequency of 50Hz, and a period of 20ms, and select the hammering function (no rotation). According to the size of the connection between the clamping part 4 and the impact hammer rod 5, make 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 a thread 52; make a pad 6 with a radius of 30cm and a thickness of 3cm. The pad 6 is made of steel. A screw hole that can be connected to the impact hammer rod 5 is arranged in the center of the pad 6. Three expansion screw 63 fixing holes are arranged around the pad 6 in an isosceles triangle. At the same time, three cable hangers 62 are arranged around the pad 6 in an isosceles triangle; three support cables 72 with hooks 74 and shock-absorbing springs are arranged; 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 cable 72. The plug 32 of the steady-state impact hammer 3 is inserted into a power socket, and the power socket is switched on and off to start the steady-state impact hammer 3 to operate.

[0111] See also Figure 1-4 First, select the surface of a relatively solid and stable rock mass 1 as the excitation point. The distance between the excitation point and the intended detection area should be more than 20m to avoid the impact vibration affecting the detection of the vibration sensor.

[0112] A plurality of mounting holes are punched at the excitation point, and the pad 6 is fixed to the surface of the rock mass 1 by using expansion screws 63; one end of the impact hammer rod 5 with the thread 52 is screwed into the screw hole 61 fixed in the center of the pad 6, and the connecting part 51 provided at the other end is fastened in cooperation with the clamping part 4; the steady-state impact hammer 3 is fixed to the cable hanger 62 around the pad 6 by using the supporting cable 72 to ensure 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 steady-state impact hammer 3 vibrates internally, and the pad 6 is hammered by the impact hammer rod 5, forming a continuous and stable impact vibration with a frequency of 50 Hz.

[0113] See also Figure 3 , continuously excite the earthquake source, and arrange two vibration sensors with a spacing of S in the same earthquake source radiation direction. The distance between the vibration sensor and the excitation point is preferably more than 20m to avoid the impact vibration affecting the detection of the vibration sensor. The vibration sensors synchronously and independently collect data for a period of 1 second (50 times the earthquake 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 the rock mass 1 can be achieved through the Rayleigh surface wave dispersion analysis method.

[0114] The Rayleigh surface wave analysis method specifically includes the following steps:

[0115] 1: Based on the vibration records obtained by the two sensors, the frequency domain is decomposed by Fourier transform to obtain Rayleigh wave harmonic signals of different frequencies f(i), wherein the Rayleigh wave harmonic signals include amplitude and phase;

[0116] 2: Calculate the phase difference radian value Φ(i) between the harmonic signals of the same frequency of the two vibration sensors, and obtain the phase velocity V(i) corresponding to the frequency f(i). The calculation formula of the phase velocity V(i) is:

[0117] V(i)=S*2*π*f(i) / Φ(i);

[0118] 3: Calculate the wavelength λ(i) of the Rayleigh wave harmonic signals of different frequencies, λ(i) = V(i) / f(i);

[0119] 4: Through the correlation between wavelength λ(i) and phase velocity V(i), the dispersion curve is obtained, and the structural state of rock mass 1 at different depths is obtained according to the dispersion curve, so as to judge the structural stability of rock mass 1. The recording point of the dispersion curve is the midpoint of the two vibration sensors.

[0120] Theoretically, Rayleigh waves with longer wavelengths are associated with deeper strata, while Rayleigh waves with shorter wavelengths are associated with shallower strata. Therefore, dispersion curves can be used to indicate the Rayleigh wave phase velocities of media at different depths. The greater the Rayleigh wave phase velocity, the better the shear resistance of the medium and the more stable the rock. Conversely, the worse the shear resistance is, the worse the rock stability is.

[0121] Figure 3 A schematic diagram of the locations of the excitation points and vibration sensors; Figure 4 The figure is a schematic diagram of the Rayleigh wave dispersion curve of this embodiment. The numbers on the horizontal axis and the dotted lines in the figure represent the recording points 1 to 10 of this embodiment. The changing curves in the figure represent the phase velocity changes of the Rayleigh waves at different recording points at different depths of the medium. Figure 4 It can be seen that compared with the velocity of Rayleigh waves with a wavelength 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, that is, a low-velocity anomaly of Rayleigh waves is presented, proving that there is loose medium below 2m in the rock mass in the vertical direction inside the two recording points 5 and 6.

[0122] By moving two vibration sensors and performing measurements and interpretations based on the same principle at different locations, the Rayleigh phase velocity distribution inside the rock mass 1 at different spatial locations can be obtained, thereby achieving the structural stability evaluation of the rock mass 1 in the test area. As an improvement, multiple sensors can be deployed at one time in the direction of earthquake source radiation, and the Rayleigh surface wave dispersion analysis method can be used for multi-point calculation and geological interpretation.

[0123] Embodiment 3:

[0124] See also Figure 1 , 2 , 5 and 6, a method for testing bad structure of rock mass 1 according to the third embodiment of the present invention comprises the following steps:

[0125] S1, selecting a vibration point on the surface of the rock mass 1 according to the intended detection area, setting the steady-state impact hammer 3 on the vibration point, and the distance L between the vibration point and the boundary of the intended detection area is greater than twice the vertical depth of the surface of the rock mass 1 to be detected;

[0126] S2, start the steady-state impact hammer 3, stable and continuous excitation source;

[0127] S3, moving the vibration sensor within the intended detection area;

[0128] S4, each of the vibration sensors obtains vibration records of the measuring points of the set grid degree point by point;

[0129] S5. According to the vibration records of the measuring points obtained by the multiple vibration sensors, the amplitude spectra of the signals with different frequencies at all the measuring points are obtained by spectrum analysis, and then the amplitude spectrum slices corresponding to the different frequencies of all the measuring points are obtained;

[0130] S6. Analyze the amplitude spectrum slices to determine whether there is an unfavorable geological structure in the rock mass 1.

[0131] Take the advanced detection of adverse geological structures on the surface of rock mass 1 during the construction of underground mining tunnels as an example to avoid encountering broken zones or water storage structures that seriously affect the construction progress and operation safety. The vertical depth of the surface of rock mass 1 to be detected is 15m.

[0132] See also Figure 1 Or 2, using the steady-state seismic source excitation device of Example 1 to perform stable and continuous excitation of the seismic source.

[0133] Use a steady-state impact hammer 3 with a power of 60J and a hammering frequency of 3000 times / minute, i.e., a period of 20 milliseconds, and select the hammering function (without rotation). According to the size of the connection between the clamping part 4 and the impact hammer rod 5, make the impact hammer rod 5, which can be fastened to the clamping part 4, and the other end is made into a cylinder with a thread 52; make a pad 6 with a radius of 30cm and a thickness of 3cm, the pad 6 is made of steel, and a screw hole that can be connected to the impact hammer rod 5 is arranged in the center of the pad 6, and three expansion screw 63 fixing holes are arranged around the pad 6 in an isosceles triangle, and three cable hangers 62 are arranged around the pad 6 in an isosceles triangle; three support cables 72 with hooks 74 and shock-absorbing springs are arranged; a connecting piece 71 is fixed in the middle of the steady-state impact hammer 3, and the connecting piece 71 can be a belt for hanging the support cable 72. Plug the plug 32 of the steady-state impact hammer 3 into the power socket, and the power socket starts the operation of the steady-state impact hammer 3 through the switch.

[0134] The distance L between the excitation point and the boundary of the intended detection area is greater than twice the vertical depth of the surface of the rock mass 1 to be detected, so a relatively solid and stable rock mass 1 surface more than 30m away from the boundary of the intended detection area is first selected as the excitation point. Make installation holes at the excitation point, and use expansion screws 63 to fix the pad 6 on the surface of the rock mass 1; screw one end of the impact hammer rod 5 with thread 52 into the screw hole 61 fixed in the center of the pad 6, and the connecting part 51 set at the other end is fastened with the clamping part 4; use three support cables 72 with shock-absorbing springs to fix the steady-state impact hammer 3 on the surface of the rock mass 1 around the pad 6 through expansion screws 63 to ensure that the steady-state impact hammer 3 is perpendicular to the plane of the pad 6; turn on the power, and the steady-state impact hammer 3 hammers the pad 6 through the head of the impact hammer rod 5, forming a continuous and stable impact vibration.

[0135] Continuously stimulate the seismic source; use a vibration sensor to obtain vibration records of a certain grid size (such as 1m*1m) at each measuring point in the intended detection area. The vibration record of each measuring point is 2 seconds long, which is 100 times the hammer cycle of 20 milliseconds. Through spectrum analysis such as Fourier transform and entropy spectrum analysis, the amplitude spectrum of different frequency signals at all measuring points can be obtained, and then the amplitude spectrum slices corresponding to different frequencies of all measuring points can be obtained, such as Figure 6 shown.

[0136] The amplitude spectrum amplitudes of different frequencies directly reflect the resonance strength of the rock mass structure. The loose structure in the rock mass will produce obvious resonance phenomenon. The high-frequency signal has a short wavelength, which represents the shallow geological structure information, while the low-frequency signal has a long wavelength, which represents the deeper geological structure information. Based on this principle, the geological structure status information from shallow to deep within the surface of the tested rock mass can be interpreted. Figure 6 The darker the local area, the higher the amplitude, and the lighter the local area, the smaller the amplitude. Figure 6 There are local areas with higher amplitudes in the detection area, so there is a loose structure on the rock surface in the local detection area; the lower the frequency corresponding to the high-amplitude area, the deeper the loose area is, and vice versa, the higher the frequency corresponding to the high-amplitude area, the shallower the loose area is.

[0137] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A steady-state source excitation device, characterized in that: It includes a steady-state impact hammer, an impact hammer rod and a backing plate; The steady-state impact hammer is used to continuously excite the 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; one end of the impact hammer rod away from the clamping part is fixedly connected to a pad, and the pad is used to be fixed on the rock surface.

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

3. The steady-state source excitation device according to claim 2, characterized in that: When the steady-state impact hammer is arranged 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; When the steady-state impact hammer is arranged on the side wall 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 side wall of the rock mass.

4. The steady-state source excitation device according to claim 2, characterized in that: The support assembly is provided with a shock absorbing member.

5. The steady-state source excitation device according to claim 2, characterized in that: The support assembly comprises a support cable, one end of which is connected to a steady-state impact hammer, and the other end of which is connected to a pad or a rock surface for fixing the steady-state impact hammer.

6. The steady-state source excitation device according to any one of claims 1 to 5, characterized in that: The pad is arranged on the surface of the rock mass by means of expansion screws.

7. The steady-state source excitation device according to any one of claims 1 to 5, characterized in that: The impact hammer rod is threadedly connected with the backing plate.

8. A method for testing the stability of rock mass structure, characterized in that: The steps include: S1. Select a shock point on the rock surface according to the intended detection area, and set a steady-state impact hammer on the shock point; S2, turn on the steady-state impact hammer, a stable and continuous excitation source; S3, multiple vibration sensors are arranged in the radiation direction of the earthquake source, and the spacing between adjacent vibration sensors is S; S4, each of the vibration sensors obtains a vibration record; S5. Vibration records obtained by multiple vibration sensors are used to analyze the stability of the geological structure inside the rock mass based on Rayleigh surface wave dispersion.

9. The rock structure stability testing method according to claim 8, characterized in that: The step S5 specifically includes the following steps: S51, performing frequency domain decomposition using Fourier transform according to vibration records obtained by multiple vibration sensors, and decomposing to obtain Rayleigh wave harmonic signals of different frequencies f(i), wherein the Rayleigh wave harmonic signals include amplitude and phase; S52, calculate the phase difference radian value Φ(i) between the harmonic signals of the same frequency of the vibration sensors in the same radiation direction, and obtain the phase velocity V(i) corresponding to the frequency f(i). The calculation formula of the phase velocity V(i) is: V(i)=S*2*π*f(i) / Φ(i); S53, calculating the wavelength λ(i) of the Rayleigh wave harmonic signals of different frequencies, λ(i)=V(i) / f(i); S54. The dispersion curve is obtained through the correlation between the wavelength λ(i) and the phase velocity V(i). The rock structure state at different depths is obtained according to the dispersion curve, so as to judge the stability of the rock structure. Rayleigh waves with longer wavelengths are associated with deeper strata, while Rayleigh waves with shorter wavelengths are associated with shallower strata. The greater the Rayleigh wave phase velocity, the better the shear resistance of the medium and the more stable the rock. Conversely, the worse the shear resistance is, the worse the rock stability is.

10. A method for testing bad rock structures, characterized in that: The steps include: S1. Select an exciting point on the rock surface according to the intended detection area, and set a steady-state impact hammer on the exciting point. The distance L between the exciting point and the boundary of the intended detection area is greater than twice the vertical depth of the rock surface to be detected; S2, turn on the steady-state impact hammer, a stable and continuous excitation source; S3, moving the vibration sensor in the intended detection area; S4, the vibration sensor obtains the vibration records of the measuring points of the set grid degree point by point; S5. According to the vibration records of the measuring points obtained by the vibration sensor, the amplitude spectra of the signals of different frequencies at all the measuring points are obtained by spectrum analysis, and then the amplitude spectrum slices corresponding to the different frequencies of all the measuring points are obtained; S6. Analyze the amplitude spectrum slices to determine whether there are adverse geological structures in the rock mass.

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