A small-scale land broadband shear wave controllable source device based on electromagnetic drive

Abstract

The present invention belongs to the technical field of land seismic exploration equipment and relates to a small-scale land broadband shear-wave vibrator device based on electromagnetic drive. The device comprises a housing, a magnetic field structure, and two coil bobbins disposed on either side of the magnetic field structure. A guide shaft is mounted between the two main side plates of the housing. The magnetic field structure is slidably sleeved outside the guide shaft and comprises two air-gap magnetic field assemblies and a bottom magnetic yoke sandwiched therebetween. The air-gap magnetic field assembly comprises an outer magnetic yoke, an inner magnetic yoke, and a first permanent magnet and a second permanent magnet connected to the ends of the inner magnetic yoke. The first and second permanent magnets are both axially magnetized but in opposite directions. One end of the coil bobbin is connected to the main side plate, and the other end is inserted into the air gap. The drive coils on the two coil bobbins are connected in series and have the same winding direction. The present invention utilizes the electromagnetic drive magnetic field structure to vibrate horizontally and transmit the electromagnetic force to the surface to excite shear wave signals. This solves the problem of insufficient excitation bandwidth of traditional hydraulic shear-wave vibrators and improves the resolution of shear-wave seismic exploration.

Description

Technical Field

[0001] The present invention belongs to the technical field of land seismic exploration equipment, and in particular relates to a small land broadband shear wave controllable source device based on electromagnetic drive. Background Art

[0002] Seismic waves are divided into body waves and surface waves; among them, body waves mainly include longitudinal waves and shear waves; the direction of vibration of longitudinal wave particles is parallel to the direction of wave propagation; while the direction of vibration of shear wave particles is perpendicular to the direction of wave propagation. Compared with longitudinal waves, the propagation speed of shear waves is significantly lower and the wavelength is shorter; the natural properties of shear waves give them obvious advantages in seismic exploration.

[0003] Land shear-wave seismic exploration is a method that uses artificially induced shear waves to propagate through underground media to investigate geological structures and lithology. Since the 1960s and 1970s, research abroad has been exploring the low velocity of shear waves to obtain higher-resolution seismic profiles. Because shear waves decay rapidly, exploration depths are generally shallow, making them a common method for high-resolution shallow-layer seismic exploration on land.

[0004] In land shear-wave seismic exploration, a shear-wave source is a key excitation device. Shear-wave sources include hammer sources and vibrators. The horizontal impulse they generate can excite horizontally polarized shear waves. Vibrators, in particular, generate low-energy-density shear-wave signals through continuous vibration. Compared to other shear-wave sources, they offer excellent repeatability and high energy efficiency, enabling safe, green, and efficient seismic exploration.

[0005] At present, the commonly used shear wave controllable source in the industry is the hydraulic shear wave controllable source, which is mainly based on hydraulic oil flow as the energy transfer medium; however, due to the limitation of the operating frequency band of the hydraulic servo valve, the excitation frequency band of the hydraulic shear wave controllable source is relatively narrow, and the maximum excitation frequency usually does not exceed 250 Hz, making it difficult to excite higher-frequency shear wave signals. The excitation frequency of the shear wave controllable source will directly affect the wavelength of the shear wave, and thus affect the resolution of the seismic profile during shallow shear wave seismic exploration on land. Summary of the Invention

[0006] In response to the shortcomings in related technologies, the present invention provides a small-scale land broadband shear wave controllable source device based on electromagnetic drive, aiming to provide a new source device for land shear wave seismic exploration, so as to solve the shortcomings of traditional hydraulic shear wave controllable sources, expand the working frequency band of shear wave controllable sources, and improve the resolution of land shallow shear wave seismic exploration.

[0007] The present invention provides a small-scale land broadband shear wave controllable source device based on electromagnetic drive, comprising:

[0008] The box body includes a bottom plate, a top plate, and two main side plates detachably connected between the bottom plate and the top plate and arranged opposite to each other; a coupling plate is detachably connected below the bottom plate to couple with the ground surface; a horizontally extending guide shaft is installed between the two main side plates;

[0009] A magnetic field structure includes two air gap magnetic field assemblies and a bottom magnetic yoke sandwiched between the two air gap magnetic field assemblies. The bottom magnetic yoke and the two air gap magnetic field assemblies are both sleeved outside the guide shaft and slidably connected to the guide shaft. Each air gap magnetic field assembly includes an outer magnetic yoke, an inner magnetic yoke, a first permanent magnet, and a second permanent magnet coaxially arranged with the guide shaft. The axial ends of the inner magnetic yoke are respectively connected to the first permanent magnet and the second permanent magnet. The first permanent magnet and the second permanent magnet are both axially magnetized but in opposite magnetization directions. The outer magnetic yoke is sleeved outside the inner magnetic yoke, the first permanent magnet, and the second permanent magnet to form an air gap. The bottom magnetic yoke is connected to the outer magnetic yoke and the second permanent magnet.

[0010] Two moving coil structures are respectively arranged on both sides of the magnetic field structure in the axial direction; each moving coil structure includes a coil frame, which includes a base plate and a cylindrical wall protruding from one side of the base plate, the base plate is connected to the main side plate, the cylindrical wall is inserted into the air gap, and the driving coil is wound on the cylindrical wall; the two driving coils of the two moving coil structures are connected in series and have the same winding direction;

[0011] When the two driving coils are connected to alternating current, the magnetic field structure vibrates horizontally along the guide axis under the action of electromagnetic force. At the same time, the electromagnetic force is transmitted to the bottom plate through the coil frame and the main side plate, and then coupled with the ground surface through the coupling plate to excite shear wave signals.

[0012] In some embodiments, a plurality of limit assemblies are provided between the bottom magnetic yoke and a main side plate, and the plurality of limit assemblies are arranged at intervals around the center of the bottom magnetic yoke. Each limit assemblies includes a first pillar and a second pillar that are coaxial and oppositely arranged. The first pillar is connected to the main side plate, and the second pillar is connected to the outer wall of the bottom magnetic yoke. A limit spring is sandwiched between the first pillar and the second pillar.

[0013] In some embodiments, a guide sleeve is sandwiched between the magnetic field structure and the guide shaft; the guide sleeve and the magnetic field structure are interference fit, and two linear bearings adapted to the guide shaft are embedded in the guide sleeve; the axial length of the guide sleeve is equal to the axial length of the magnetic field structure, and pressure plates are respectively connected to both ends of the guide sleeve, and the two pressure plates are also respectively pressed against the axial ends of the magnetic field structure.

[0014] In some embodiments, the inner magnetic yoke includes two first magnetic yoke rings and a second magnetic yoke ring sandwiched between the two first magnetic yoke rings, and the two first magnetic yoke rings are respectively connected to the first permanent magnet and the second permanent magnet; the inner diameter of the second magnetic yoke ring is larger than the inner diameter of the first magnetic yoke ring.

[0015] In some embodiments, an acceleration sensor is provided on the outer wall of the bottom magnetic yoke; a measuring plate is also protruded from the outer wall of the bottom magnetic yoke, a fixing plate is protruded from the bottom surface of the top plate and is arranged opposite to the measuring plate, a displacement sensor is mounted on the fixing plate, and a probe of the displacement sensor is in contact with the measuring plate.

[0016] In some embodiments, an external interface is opened on the top plate, and an interface cover is connected to the external interface. The interface cover is provided with a power interface for providing alternating current to the driving coil and a signal transmission interface for transmitting monitoring information of the acceleration sensor and the displacement sensor.

[0017] In some embodiments, a support plate is provided at the bottom of each main side panel so that the cross-section of the main side panel is ⊥-shaped, and the support plate is connected to the bottom panel; the box body also includes two secondary side panels that are detachably connected between the bottom panel and the top panel and are arranged opposite to each other, and each secondary side panel is also connected to the two main side panels respectively.

[0018] In some embodiments, a plurality of axially extending slots are formed in a circumferential direction of the cylindrical wall of each coil bobbin.

[0019] In some embodiments, two stirrups are protruded along the axial direction on the outer wall of the cylinder of each coil skeleton, and the driving coil is wound on the cylinder wall between the two stirrups; insulating paper is pasted on the cylinder wall between the two stirrups.

[0020] In some of the embodiments, when the small-scale terrestrial broadband shear-wave controllable source device is used for seismic exploration in a hard surface environment, the coupling plate is a rubber plate with a preset thickness and hardness, and a plurality of anti-slip protrusion structures are provided on the bottom surface of the rubber plate; when the small-scale terrestrial broadband shear-wave controllable source device is used for seismic exploration in a soft surface environment, the coupling plate is a steel plate with a preset thickness, and a plurality of triangular pyramid structures are provided on the bottom surface of the steel plate.

[0021] Based on the above technical solution, the small-scale land broadband shear wave controllable source device based on electromagnetic drive in the embodiment of the present invention, through the setting of a magnetic field structure with a double air gap magnetic field component and the setting of two moving coil structures located on both sides of the magnetic field structure, can use the electromagnetic drive magnetic field structure to vibrate horizontally, and transmit the electromagnetic force to the surface to excite shear wave signals, thereby expanding the working frequency band of the shear wave controllable source and improving the resolution of shallow shear wave seismic exploration on land, thereby solving the problem of insufficient excitation frequency band width of traditional hydraulic shear wave controllable sources. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0023] Figure 1 It is an overall schematic diagram of the small-sized land broadband shear wave controllable source device of the present invention;

[0024] Figure 2 A cross-sectional view of a small-sized land broadband shear wave vibrator device according to the present invention;

[0025] Figure 3 An exploded view of the small-scale land broadband shear wave controllable source device of the present invention;

[0026] Figure 4 Schematic diagram of the structure of the coil skeleton in the present invention;

[0027] Figure 5 This is a schematic diagram of the magnetic field structure of the present invention when it vibrates horizontally;

[0028] Figure 6 It is a schematic diagram of the local structure of the top plate and the bottom magnetic yoke in the present invention.

[0029] In the figure: 10, box body; 11, bottom plate; 12, top plate; 121, interface cover plate; 122, fixed plate; 13, main side plate; 131, support plate; 14, secondary side plate; 15, guide shaft; 16, shaft cover plate; 20, magnetic field structure; 21, air gap magnetic field assembly; 211, outer magnetic yoke; 212, inner magnetic yoke; 2121, first magnetic yoke ring; 2122, second magnetic yoke ring; 213, first permanent magnet; 214, second permanent magnet; 22, bottom magnetic yoke; 221, measuring plate; 23, guide sleeve; 24, pressure plate; 201, air gap; 30, moving coil structure; 31, coil skeleton; 311, seat plate; 312, cylinder wall; 313, slot; 314, stirrup; 40, limit assembly; 41, first pillar; 42, second pillar; 43, limit spring. DETAILED DESCRIPTION

[0030] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0031] In the description of the present invention, it should be understood that the terms "center", "lateral", "longitudinal", "up", "down", "top", "bottom", "inside", "outside", "left", "right", "front", "back", "vertical", "horizontal", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0032] The terms "first," "second," etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance or to implicitly indicate the quantity of the technical features indicated. Thus, a feature specified as "first," "second," etc. may explicitly or implicitly include one or more of the features.

[0033] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to direct connections, indirect connections through an intermediary, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0034] refer to Figures 1-6 As shown, the present invention provides a small-scale terrestrial broadband shear wave controllable source device based on electromagnetic drive, which includes a box 10, a magnetic field structure 20 placed in the box 10 and two moving coil structures 30.

[0035] The box body 10 is an assembled structure, comprising a top plate 12 and a bottom plate 11 arranged opposite each other in the upper and lower directions, and two main side plates 13 detachably connected between the bottom plate 11 and the top plate 12 and arranged opposite each other. A coupling plate is detachably connected to the bottom of the bottom plate 11, and the coupling plate is used to couple with the ground surface; the coupling plate can be removed and replaced as needed to adapt to different surface environments. A horizontally extending guide shaft 15 is installed between the two main side plates 13; specifically, the two ends of the guide shaft 15 pass through the two main side plates 13 respectively, and a shaft cover plate 16 is provided on the outside of each main side plate 13. The center of the shaft cover plate 16 is connected to the guide shaft 15 by bolts, and the circumference of the shaft cover plate 16 is connected to the main side plates 13 by multiple bolts, thereby realizing the assembly of the guide shaft 15 between the two main side plates 13.

[0036] The magnetic field structure 20 includes two air gap magnetic field components 21 and a bottom magnetic yoke 22, and the bottom magnetic yoke 22 is clamped between the two air gap magnetic field components 21; the bottom magnetic yoke 22 and the two air gap magnetic field components 21 are both sleeved outside the guide shaft 15 and slidably connected to the guide shaft 15, that is, the magnetic field structure 20 can move back and forth along the length direction of the guide shaft 15; the guide shaft 15 is a chrome-plated optical shaft with high hardness, high wear resistance and good corrosion resistance, providing support and movement guidance for the magnetic field structure 20.

[0037] Each air gap magnetic field assembly 21 includes an outer magnetic yoke 211, an inner magnetic yoke 212, a first permanent magnet 213, and a second permanent magnet 214, all coaxially arranged with the guide shaft 15. Specifically, the outer diameters of the inner magnetic yoke 212, the first permanent magnet 213, and the second permanent magnet 214 are equal, and the outer diameters of the outer magnetic yoke 211 and the bottom magnetic yoke 22 are equal. The axial ends of the inner magnetic yoke 212 are connected to the first permanent magnet 213 and the second permanent magnet 214, respectively. The first permanent magnet 213 and the second permanent magnet 214 are both axially magnetized but in opposite directions. In other words, the axial ends of the first permanent magnet 213 and the second permanent magnet 214 are respectively north and south poles, and the ends of the first permanent magnet 213 and the second permanent magnet 214 connected to the inner magnetic yoke 212 are both north poles or both south poles. The outer yoke 211 is sleeved over the inner yoke 212, the first permanent magnet 213, and the second permanent magnet 214 to form an air gap 201. Specifically, the inner diameter of the outer yoke 211 is equal to the sum of the outer diameter of the inner yoke 212 and twice the width of the air gap 201, and the axial length of the outer yoke 211 is equal to the sum of the axial lengths of the inner yoke 212 and the two permanent magnets. The two ends of the bottom yoke 22 are respectively connected to the outer yoke 211 and the second permanent magnet 214 of the two air gap magnetic field assemblies 21. Furthermore, the first permanent magnet 213 and the second permanent magnet 214 are both made of high-energy needle iron boron material, exhibiting large remanence and strong coercive force. The inner yoke 212, the outer yoke 211, and the bottom yoke 22 are all made of high-permeability magnetic materials. The bottom yoke 22 and the air gap magnetic field assembly 21 are fixed together by magnetic attraction, without the need for bolts.

[0038] To further illustrate, each air gap magnetic field assembly 21 has two main magnetic circuits. This example uses the example of a first permanent magnet 213 and a second permanent magnet 214 with one end connected to the inner yoke 212 having a north pole. One magnetic circuit consists of magnetic flux lines originating from the north pole of the first permanent magnet 213, passing through the inner yoke 212, the air gap 201, the outer yoke 211, and finally returning to the south pole of the first permanent magnet 213. The other magnetic circuit consists of magnetic flux lines originating from the north pole of the second permanent magnet 214, passing through the inner yoke 212, the air gap 201, the outer yoke 211, and the bottom yoke 22, and finally returning to the south pole of the bottom permanent magnet. The radial magnetic flux intensities generated by the first and second permanent magnets 213 and 214 in the air gap 201 are in the same direction. Each air gap magnetic field assembly 21 is dual-permanent magnet excitation. This dual-permanent magnet configuration enables the formation of a strong static air gap magnetic field between the inner yoke 212 and the outer yoke 211. The entire magnetic field structure 20 has two symmetrical air-gap magnetic fields, and the two air-gap magnetic fields share the same bottom magnetic yoke 22 .

[0039] Two moving coil structures 30 are disposed on either side of the magnetic field structure 20 in the axial direction. Each moving coil structure 30 includes a coil bobbin 31 coaxially arranged with the guide shaft 15. The coil bobbin 31 is made of aluminum alloy and comprises a base plate 311 and a cylindrical wall 312 protruding from one side of the base plate 311. The base plate 311 is connected to the main side plate 13. The cylindrical wall 312 is a thin-walled cylindrical structure and is inserted into the air gap 201. Specifically, the inner diameter of the cylindrical wall 312 is larger than the outer diameter of the inner magnetic yoke 212, and the outer diameter of the cylindrical wall 312 is smaller than the inner diameter of the outer magnetic yoke 211. A drive coil (not shown) is wound around the cylindrical wall 312, and the drive coil is inserted into the air gap 201. The two drive coils in the two moving coil structures 30 are connected in series and have the same winding direction.

[0040] When the two driving coils are connected to the alternating current, they will be affected by the two air gap magnetic fields formed by the magnetic field structure 20 respectively, generating electromagnetic force; and because the two driving coils are connected in series and have the same winding direction, the direction of the electromagnetic force on the two air gap magnetic field components 21 is always the same, and the electromagnetic force will manifest as a pulling force on the magnetic field structure 20 in one air gap magnetic field and as a thrust on the magnetic field structure 20 in the other air gap magnetic field. Therefore, the magnetic field structure 20 moves along the guide shaft 15 under the combined action of the pulling force and the thrust, that is, the two air gap magnetic field components 21 move synchronously and in the same direction along the guide shaft 15; because the direction and magnitude of the alternating current change periodically with time, the direction of the electromagnetic force also changes with time, so the magnetic field structure 20 will vibrate horizontally along the guide shaft 15 under the action of the electromagnetic force, that is, the magnetic field structure 20 is a moving component, which moves back and forth between the two main side plates 13 according to the excitation signal waveform of the alternating current, as shown in FIG. Figure 5As shown; at the same time, the electromagnetic force also acts on the coil bobbin 31 in the form of a reaction force. The electromagnetic force is transmitted to the base plate 11 through the coil bobbin 31 and the main side plate 13, and then coupled with the ground surface through the coupling plate to excite a shear wave signal for land shear wave seismic exploration. Further explanation: Because this embodiment uses electromagnetic drive technology, it can significantly expand the operating frequency band of the shear wave controllable source. Its maximum excitation frequency can reach several thousand hertz, which is far greater than the maximum excitation frequency of traditional hydraulic shear wave controllable sources. Therefore, this embodiment can excite higher-frequency shear wave signals, thereby improving the resolution of shear wave seismic exploration.

[0041] In the above-mentioned schematic embodiment, the magnetic field strength in each air gap 201 area is significantly enhanced by the arrangement of dual permanent magnets in each air gap magnetic field assembly 21, thereby improving the electromagnetic force driving the magnetic field structure 20; by the symmetrical arrangement of the two air gap magnetic field assemblies 21 and the symmetrical arrangement of the two moving coil structures 30, and inserting the driving coil in the moving coil structure 30 into the air gap magnetic field, the magnetic field structure 20 with dual air gap magnetic field assemblies 21 can be driven to vibrate horizontally by electromagnetic force after the driving coil is connected to the alternating current, and the electromagnetic force is transmitted to the coupling plate at the bottom of the box 10 to couple with the surface and excite a shear wave signal, thereby providing a new source device based on electromagnetic drive for land shear wave seismic exploration, expanding the working frequency band of the shear wave controllable source, significantly improving the resolution of shear wave seismic exploration, and realizing high-resolution underground imaging during land shallow shear wave seismic exploration.

[0042] refer to Figure 2 、 Figure 3 、 Figure 5 As shown, in some embodiments, a plurality of limit assemblies 40 are further provided between the bottom magnetic yoke 22 and a main side plate 13. The plurality of limit assemblies 40 are spaced apart around the center of the bottom magnetic yoke 22. Each limit assembly 40 includes a first support 41 and a second support 42 that are coaxially and oppositely disposed. The first support 41 is connected to the main side plate 13, and the second support 42 is connected to the outer wall of the bottom magnetic yoke 22. A limit spring 43 is sandwiched between the first support 41 and the second support 42. Further, when the magnetic field structure 20 is in a preset initial vibration position, the limit spring 43 is generally at its natural length. When the magnetic field structure 20 vibrates horizontally and reciprocates along the guide shaft 15, the length of the limit spring 43 changes accordingly, causing it to be stretched or compressed. Under the action of the spring force of the limit spring 43, the limit position of the magnetic field structure 20 during reciprocating movement can be limited.

[0043] refer to Figure 2 、 Figure 3As shown, in some embodiments, a guide sleeve 23 is sandwiched between the magnetic field structure 20 and the guide shaft 15; the guide sleeve 23 and the magnetic field structure 20 have an interference fit so that the two are reliably connected as one. The guide sleeve 23 is embedded with two linear bearings (not shown) that are compatible with the guide shaft 15. The axial length of the guide sleeve 23 is equal to the axial length of the magnetic field structure 20. The two ends of the guide sleeve 23 are respectively connected to pressure plates 24. The outer diameter of the pressure plates 24 is larger than the outer diameter of the guide sleeve 23. The two pressure plates 24 are also respectively pressed against the axial ends of the magnetic field structure 20, thereby fixing the guide sleeve 23 and the magnetic field structure 20 together to prevent relative movement between the guide sleeve 23 and the magnetic field structure 20.

[0044] refer to Figure 2 、 Figure 3 、 Figure 5 As shown, in some embodiments, the inner magnetic yoke 212 in each air-gap magnetic field assembly 21 includes two first magnetic yoke rings 2121 and a second magnetic yoke ring 2122 sandwiched between the two first magnetic yoke rings 2121. The two first magnetic yoke rings 2121 are respectively connected to the first permanent magnet 213 and the second permanent magnet 214. The outer diameters of the first magnetic yoke ring 2121 and the second magnetic yoke ring 2122 are the same and equal to the outer diameters of the first permanent magnet 213 and the second permanent magnet 214, while the inner diameter of the second magnetic yoke ring 2122 is larger than the inner diameter of the first magnetic yoke ring 2121. This arrangement is mainly based on the distribution of magnetic flux lines of the magnetic field structure 20. The distribution area of ​​the magnetic flux lines in the inner magnetic yoke 212 is mainly concentrated in an area at a certain depth from its surface. Therefore, under the premise of ensuring the magnetic circuit performance of the magnetic field structure 20, by providing the second magnetic yoke ring 2122 with a larger inner diameter in the middle section of the inner magnetic yoke 212, the manufacturing cost and weight of the inner magnetic yoke 212 are reduced, thereby improving the portability of the device.

[0045] refer to Figure 2 、 Figure 5 、 Figure 6 As shown, in some embodiments, an acceleration sensor (not shown) is provided on the outer wall of the bottom magnetic yoke 22 to monitor the vibration acceleration of the magnetic field structure 20 in real time. A measurement plate 221 is also protruding from the outer wall of the bottom magnetic yoke 22. A fixing plate 122 is protruding from the bottom surface of the top plate 12, positioned opposite the measurement plate 221. A displacement sensor (not shown) is mounted on the fixing plate 122. The displacement sensor probe contacts the measurement plate 221 to monitor the vibration displacement of the magnetic field structure 20 in real time. Thus, by providing a velocity sensor and a displacement sensor, real-time monitoring of the vibration state of the magnetic field structure 20 is achieved.

[0046] refer to Figure 1-Figure 3As shown, in some embodiments, an external interface is opened on the top plate 12, and an interface cover 121 is connected to the external interface. The interface cover 121 is provided with a power supply interface for providing alternating current to the driving coil and a signal transmission interface for transmitting monitoring information of the acceleration sensor and the displacement sensor; thereby, remote control and communication of the land broadband shear wave controllable source device can be realized.

[0047] refer to Figure 1-Figure 3 As shown, in some embodiments, a support plate 131 is provided at the bottom of each main side panel 13. The support plate 131 extends horizontally, forming a ⊥-shaped cross-section of the main side panel 13. The support plate 131 is detachably connected to the bottom panel 11 by bolts, thereby achieving a detachable connection between the main side panels 13 and the bottom panel 11. The provision of the support plate 131 enhances the connection strength and stability between the main side panels 13 and the bottom panel 11. The box 10 also includes two secondary side panels 14 detachably connected between the bottom panel 11 and the top panel 12 and arranged opposite each other. Each secondary side panel 14 is also connected to the two main side panels 13, thereby forming the entire box 10 into a closed structure that is more sturdy, stable, and portable.

[0048] refer to Figure 4 As shown, in some embodiments, a plurality of axially extending slots 313 are spaced apart in the circumferential direction on the cylindrical wall 312 of each coil skeleton 31; when the driving coil is connected to the alternating current, corresponding eddy currents are induced on the coil skeleton 31 made of aluminum alloy to generate a thermal effect. By setting the slots 313, the thermal effect generated by the eddy current can be effectively reduced.

[0049] refer to Figure 2 、 Figure 4 As shown, in some embodiments, two stirrups 314 are provided axially along the outer wall of the cylindrical wall 312 of each coil bobbin 31; the drive coil is a high-temperature-resistant copper enameled wire, which is wound in a uniform multi-layer manner on the cylindrical wall 312 between the two stirrups 314, with the raised height of the stirrups 314 corresponding to the height of the wound drive coil; the two drive coil windings in the two moving coil structures 30 are connected in series and ultimately connected to the power interface on the interface cover 121. When the drive coil is subjected to electromagnetic force, the drive coil does not move relative to the coil bobbin 31 due to the restriction and constraint of the two stirrups 314, and the drive coil and coil bobbin 31 move synchronously; a setting glue can be applied to the outer wall of the cylindrical wall 312 and the drive coil to further ensure that the drive coil and the coil bobbin 31 do not move relative to each other. Furthermore, to prevent the current from being conducted to the coil frame 31 after being energized due to wear of the enameled wire when the drive coil is wound, insulating paper is pasted on the cylinder wall 312 between the two stirrups 314 to ensure insulation between the drive coil and the coil frame 31.

[0050] In some embodiments, when the small-scale terrestrial broadband shear-wave controllable source device is used for seismic exploration in a hard surface environment, the coupling plate is a rubber plate with a preset thickness and hardness, and the bottom surface of the rubber plate is provided with a plurality of anti-slip protrusion structures; when the small-scale terrestrial broadband shear-wave controllable source device is used for seismic exploration in a soft surface environment, the coupling plate is a steel plate with a preset thickness, and the bottom surface of the steel plate is provided with a plurality of triangular pyramid structures; thereby, suitable coupling plates can be installed according to different terrains, thereby improving the excitation effect of the shear-wave controllable source device in different surface environments and improving the environmental adaptability of the shear-wave controllable source device.

[0051] In summary, the small-scale land broadband shear wave controllable source device based on electromagnetic drive of the present invention has a simple and compact structure, is easy to manufacture and assemble, and has strong practicality; through the setting of the magnetic field structure 20 with a double air gap magnetic field component 21 and the setting of two moving coil structures 30 located on both sides of the magnetic field structure 20, it can use electromagnetic force to drive the magnetic field structure 20 to vibrate horizontally after the driving coil is connected to the alternating current, and transmit the electromagnetic force to the surface to excite the shear wave signal, thereby providing a new source device based on electromagnetic drive for land shear wave seismic exploration, solving the problem of insufficient excitation bandwidth of traditional hydraulic shear wave controllable source, expanding the working frequency band of shear wave controllable source, improving the resolution of shear wave seismic exploration, and realizing high-resolution underground imaging during land shallow shear wave seismic exploration, which can be suitable for land shallow seismic exploration scenes such as cities.

[0052] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0053] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the same. Although the present invention has been described in detail with reference to preferred embodiments, persons of ordinary skill in the art should understand that the specific implementation methods of the present invention may still be modified or some technical features may be replaced by equivalents without departing from the spirit of the technical solutions of the present invention, and all of these should be included in the scope of the technical solutions for which protection is sought.

Claims

1. A small-scale land-based broadband shear wave controllable source device based on electromagnetic drive, characterized in that: include: The box body includes a bottom plate, a top plate, and two main side plates detachably connected between the bottom plate and the top plate and arranged opposite to each other; a coupling plate is detachably connected below the bottom plate to couple with the ground surface; a horizontally extending guide shaft is installed between the two main side plates; The magnetic field structure includes two air gap magnetic field components and a bottom magnetic yoke sandwiched between the two air gap magnetic field components. The bottom magnetic yoke and the two air gap magnetic field components are both sleeved on the outside of the guide shaft and slidably connected to the guide shaft; a guide sleeve is sandwiched between the magnetic field structure and the guide shaft, the guide sleeve and the magnetic field structure have an interference fit, and two linear bearings adapted to the guide shaft are embedded in the guide sleeve, the axial length of the guide sleeve is equal to the axial length of the magnetic field structure, and the two ends of the guide sleeve are respectively connected to pressure plates, and the two pressure plates are also respectively pressed against the axial ends of the magnetic field structure; each of the air gap magnetic field components includes an outer magnetic yoke coaxially arranged with the guide shaft, an inner magnetic yoke, a first permanent magnet and a second permanent magnet; the inner magnetic yoke includes two first magnetic yoke rings, a first magnetic yoke ring sandwiched between the two first magnetic yoke rings a second magnetic yoke ring between the two, the inner diameter of the second magnetic yoke ring is larger than the inner diameter of the first magnetic yoke ring, the two first magnetic yoke rings are respectively connected to the first permanent magnet and the second permanent magnet, the first permanent magnet and the second permanent magnet are both axially magnetized but in opposite directions; the outer magnetic yoke is sleeved on the outside of the inner magnetic yoke, the first permanent magnet and the second permanent magnet to form an air gap; the bottom magnetic yoke is connected to the outer magnetic yoke and the second permanent magnet; a plurality of limit assemblies are further provided between the bottom magnetic yoke and a main side plate, and the plurality of limit assemblies are arranged at intervals around the center of the bottom magnetic yoke, each of the limit assemblies includes a first pillar and a second pillar that are coaxial and oppositely arranged, the first pillar is connected to the main side plate, the second pillar is connected to the outer wall of the bottom magnetic yoke, and a limit spring is sandwiched between the first pillar and the second pillar; Two moving coil structures are respectively arranged on both sides of the magnetic field structure in the axial direction; each moving coil structure includes a coil skeleton, and the coil skeleton includes a base plate and a cylindrical wall protruding from one side of the base plate, the base plate is connected to the main side plate, the cylindrical wall is inserted into the air gap, and a driving coil is wound on the cylindrical wall; the two driving coils of the two moving coil structures are connected in series and have the same winding direction; When the two driving coils are connected to an alternating current, the magnetic field structure vibrates horizontally along the guide axis under the action of electromagnetic force. At the same time, the electromagnetic force is transmitted to the bottom plate through the coil frame and the main side plate, and then coupled with the ground surface through the coupling plate to excite a shear wave signal.

2. The small-scale land-based broadband shear wave controllable source device based on electromagnetic drive according to claim 1 is characterized in that: An acceleration sensor is provided on the outer wall of the bottom magnetic yoke; a measuring plate is also protruded from the outer wall of the bottom magnetic yoke, a fixing plate is protruded from the bottom surface of the top plate and is arranged opposite to the measuring plate, a displacement sensor is installed on the fixing plate, and a probe of the displacement sensor is in contact with the measuring plate.

3. The small-scale land-based broadband shear wave controllable source device based on electromagnetic drive according to claim 2, characterized in that: An external interface is provided on the top plate, an interface cover is connected to the external interface, and a power interface for providing alternating current to the driving coil and a signal transmission interface for transmitting monitoring information of the acceleration sensor and the displacement sensor are provided on the interface cover.

4. The small-scale land-based broadband shear wave controllable source device based on electromagnetic drive according to claim 1, characterized in that: A support plate is provided at the bottom of each main side panel so that the cross-section of the main side panel is ⊥-shaped, and the support plate is connected to the bottom panel; the box body also includes two secondary side panels that are detachably connected between the bottom panel and the top panel and are arranged opposite to each other, and each secondary side panel is also connected to the two main side panels respectively.

5. The small-scale land-based broadband shear wave controllable source device based on electromagnetic drive according to claim 1, characterized in that: A plurality of axially extending slots are spaced apart in the circumferential direction on the cylindrical wall of each coil skeleton.

6. The small-scale land-based broadband shear wave controllable source device based on electromagnetic drive according to claim 1, characterized in that: Two stirrups are protruded along the axial direction of the outer wall of the cylinder wall of each coil skeleton, and the driving coil is wound on the cylinder wall between the two stirrups; insulating paper is pasted on the cylinder wall between the two stirrups.

7. The small-scale land-based broadband shear wave controllable source device based on electromagnetic drive according to claim 1, characterized in that: When the small-scale land broadband shear wave controllable source device is used for seismic exploration in a hard surface environment, the coupling plate is a rubber plate with a preset thickness and hardness, and the bottom surface of the rubber plate is provided with a plurality of anti-slip protrusion structures; when the small-scale land broadband shear wave controllable source device is used for seismic exploration in a soft surface environment, the coupling plate is a steel plate with a preset thickness, and the bottom surface of the steel plate is provided with a plurality of triangular pyramid structures.

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