A bridge type acoustic wave transducer for testing geological soil compression and shear wave velocities

Abstract

The application provides a bridge type acoustic wave transducer for testing compression wave and shear wave velocity of geological soil, comprising a control circuit and a piezoelectric ceramic module, wherein the piezoelectric ceramic module comprises four piezoelectric ceramic tubes C1, C2, C3 and C4 connected through a bridge circuit; when testing the compression wave, the control circuit sends a first test signal to C1, C2, C3 and C4, so that the compression wave signals emitted by C1, C2, C3 and C4 are synchronous and same direction; when testing the shear wave, the control circuit sends a second test signal to C1, C2, C3 and C4, so that the compression wave signals emitted by C1 and C2 are synchronous and opposite direction, the compression wave signals emitted by C3 and C4 are synchronous and opposite direction, the compression wave signals emitted by C1 and C3 are synchronous and same direction, and the compression wave signals emitted by C2 and C4 are synchronous and same direction; the shear wave signals emitted by C1, C2, C3 and C4 are synchronous and same direction. The application can test the compression wave velocity of geological soil of categories 1-4 and the shear wave velocity of geological soil of categories 5-8.

Description

Technical Field

[0001] This invention relates to the field of acoustic wave detection technology, and in particular to a bridge-type acoustic transducer for testing the compression wave velocity and shear wave velocity of geological soil (classes 1-4) and geological soil (classes 5-8). Background Technology

[0002] Currently, the trans-hole ultrasonic method is commonly used for geological exploration to obtain the actual acoustic parameters of the rock mass on-site, which are then used to classify the properties of the geological soil. The specific testing method involves drilling two test holes in the geological soil, placing transducers inside, and then the ultrasonic instrument's main unit excites the transmitting transducers to emit sound wave signals. After the sound waves penetrate the geological soil, the receiving transducers receive the sound wave signals and convert them into electrical signals, which are then transmitted to the ultrasonic instrument's main unit. The main unit analyzes the data to obtain the time (acoustic time value) it takes for the sound waves (compression waves) to penetrate the rock mass. This allows for the calculation of the sound wave velocity in the geological soil. The following standards currently describe the specific testing methods: Standard for Testing Methods of Engineering Rock Mass (BG / T 50266-2013), Standard for Classification of Engineering Rock Mass (GB 50218-94), Test Procedure for Physical and Mechanical Properties of Rock (DY-94-(1986)), Test Procedure for Rocks in Water Conservancy and Hydropower Engineering (SL264-2001), and Test Procedure for Rocks in Water Conservancy and Hydropower Engineering (DL / T5368-2007).

[0003] This method is mainly used for testing the compressive wave velocity of soils classified as 5-8. However, for soils classified as 1-4, the sound waves attenuate significantly during propagation due to the soil's properties, leading to waveform distortion. In severe cases, the sound signal may even be submerged in noise. The acoustic instrument may not be able to accurately read, or at all, the time it takes for the sound wave to penetrate the soil (sound time value), thus making it impossible to accurately calculate the compressive wave velocity (resulting in an underestimation) or obtain any test results at all.

[0004] In addition, existing tests only measure the compression wave velocity of soils in categories 5-8, and the shear wave velocity of soils in the field cannot yet be measured using the trans-hole ultrasonic method. Summary of the Invention

[0005] To address the aforementioned problems, the present invention aims to provide a bridge-type acoustic transducer for testing the compression wave and shear wave velocities of geological soil, thereby solving the problem that existing methods using trans-hole ultrasonic methods for geological exploration are insufficient for testing the compression wave velocities of Class 1-4 geological soils and the shear wave velocities of Class 5-8 geological soils.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A bridge-type acoustic transducer for testing the compression and shear wave velocities of geological soil is disclosed. The bridge-type acoustic transducer includes a control circuit and a piezoelectric ceramic module encapsulated in a housing. The piezoelectric ceramic module is electrically connected to the control circuit. The piezoelectric ceramic module includes four piezoelectric ceramic tubes, namely C1, C2, C3, and C4, which are connected by a bridge circuit.

[0008] When testing the compressed wave, the control circuit sends a first test signal to C1, C2, C3, and C4, so that the waveforms of the compressed wave signals emitted by C1, C2, C3, and C4 remain synchronized and in the same direction.

[0009] During the shear wave test, the control circuit sends a second test signal to C1, C2, C3, and C4, causing the waveforms of the compressed wave signals emitted by C1 and C2 to remain synchronously reversed, the waveforms of the compressed wave signals emitted by C3 and C4 to remain synchronously reversed, the waveforms of the compressed wave signals emitted by C1 and C3 to remain synchronously in the same direction, and the waveforms of the compressed wave signals emitted by C2 and C4 to remain synchronously in the same direction; simultaneously, the waveforms of the shear wave signals emitted by C1, C2, C3, and C4 to remain synchronously in the same direction.

[0010] Preferably, the bridge acoustic transducer includes a first bridge acoustic transducer installed at the transmitting end and a second bridge acoustic transducer installed at the receiving end.

[0011] When testing the compressed wave, at the transmitting end, the control circuit in the first bridge acoustic transducer sends a first test signal to C1, C2, C3, and C4 in the first bridge acoustic transducer, so that the waveforms of the compressed wave signals emitted by C1, C2, C3, and C4 in the first bridge acoustic transducer remain synchronized and in the same direction.

[0012] At the receiving end, the waveforms of the compressed wave signals received by C1, C2, C3, and C4 in the second bridge acoustic transducer remain synchronized and in the same direction;

[0013] During shear wave testing, at the transmitting end, the control circuit in the first bridge acoustic transducer sends a second test signal to C1, C2, C3, and C4 in the first bridge acoustic transducer, causing the waveforms of the compressed wave signals emitted by C1 and C2 in the first bridge acoustic transducer to remain synchronously reversed, the waveforms of the compressed wave signals emitted by C3 and C4 to remain synchronously reversed, the waveforms of the compressed wave signals emitted by C1 and C3 to remain synchronously in the same direction, and the waveforms of the compressed wave signals emitted by C2 and C4 to remain synchronously in the same direction; simultaneously, the waveforms of the shear wave signals emitted by C1, C2, C3, and C4 in the first bridge acoustic transducer remain synchronously in the same direction.

[0014] At the receiving end, the waveforms of the compressed wave signals received by C1, C2, C3, and C4 in the second bridge acoustic transducer remain synchronously reversed; the waveforms of the compressed wave signals received by C3 and C4 remain synchronously reversed; the waveforms of the compressed wave signals received by C1 and C3 remain synchronously in the same direction; and the waveforms of the compressed wave signals received by C2 and C4 remain synchronously in the same direction. At the same time, the waveforms of the shear wave signals received by C1, C2, C3, and C4 in the second bridge acoustic transducer remain synchronously in the same direction.

[0015] Preferably, a cable is provided in the middle of the bridge-type acoustic transducer, and multiple conductors branch off from the cable to connect to the positive and negative terminals of C1, C2, C3, and C4 respectively. The cable is wrapped with a sealing rubber sleeve.

[0016] Preferably, the housing of the bridge-type acoustic transducer is a carbon fiber tube.

[0017] Preferably, a prestressed glass fiber ribbon is provided between adjacent piezoelectric ceramic tubes in the piezoelectric ceramic module.

[0018] Preferably, a primary adhesive layer is provided on the outer side of the piezoelectric ceramic module, and a secondary adhesive layer is provided between the primary adhesive layer and the housing.

[0019] Preferably, a centralizer and a counterweight are provided at the tail end of the bridge-type acoustic transducer.

[0020] Preferably, the control circuit includes a positive voltage input terminal, a negative voltage input terminal, and four signal output terminals, which respectively output corresponding test signals to the four piezoelectric ceramic tubes C1, C2, C3, and C4.

[0021] Preferably, the bridge-type acoustic transducer includes a first bridge-type acoustic transducer installed at the transmitting end and a second bridge-type acoustic transducer installed at the receiving end; the specific testing process is as follows:

[0022] The first step is to drill holes at the test site. The distance between two test holes should be 1-3 meters, the hole diameter should be 75-100 mm, and the drilling depth should be determined according to the exploration requirements. The holes should be filled with water, with a density not exceeding 1.15 g / cm³. 3 ;

[0023] The second step is to place the first bridge-type acoustic transducer in a test borehole, with one end of the first bridge-type acoustic transducer connected to the transmitting end of the non-metallic ultrasonic instrument host; and to place the second bridge-type acoustic transducer in another test borehole, with one end of the second bridge-type acoustic transducer connected to the receiving end of the non-metallic ultrasonic instrument host.

[0024] The third step is to start the test. The non-metallic ultrasonic instrument host sends an electrical signal to the first bridge acoustic transducer. The control system of the non-metallic ultrasonic instrument host controls the high-voltage transmitting module to send a set of electrical signals with a frequency between 5KHz and 300KHz.

[0025] The fourth step involves the electrical signal being controlled by the control circuit. Based on the test compression wave or shear wave, the circuit sends corresponding first or second control signals to C1, C2, C3, and C4. In this way, the electrical signal is converted into an acoustic signal after passing through the first bridge acoustic transducer. The acoustic signal penetrates the tested soil and reaches the second bridge acoustic transducer.

[0026] Fifth step: After the second bridge acoustic transducer collects the acoustic signal, the control system of the non-metallic ultrasonic instrument host processes the acoustic signals received by C1, C2, C3 and C4 respectively, and obtains the complete electrical signal through the control circuit.

[0027] The sixth step involves the non-metallic ultrasonic instrument host analyzing the obtained electrical signals to obtain the acoustic parameters of the tested geological soil: compression wave velocity or shear wave velocity.

[0028] The beneficial effects of the technical solution provided by this invention include at least the following:

[0029] (1) When testing compression waves, this invention connects four piezoelectric ceramic tubes via a bridge circuit. Through circuit design, the emitted signal intensity is amplified by 2-4 times compared to an acoustic transducer made of a single piezoelectric ceramic tube. Similarly, by connecting four piezoelectric ceramic tubes via a bridge circuit, this invention amplifies the received signal intensity by 2-4 times compared to an acoustic transducer made of a single piezoelectric ceramic tube. Therefore, this invention solves the problem of the difficulty in testing the compression wave velocity of soils classified as Class 1-4 in existing technologies.

[0030] (2) When testing shear waves, this invention connects four piezoelectric ceramic tubes via a bridge circuit. Through circuit design, the intensity of the emitted shear wave signal is amplified by four times compared to an acoustic transducer made of a single piezoelectric ceramic tube. This invention connects four piezoelectric ceramic tubes via a bridge circuit. Through circuit design, the intensity of the received shear wave signal is amplified by four times compared to an acoustic transducer made of a single piezoelectric ceramic tube.

[0031] This invention, through the design of a compensation circuit, can effectively filter out the influence of compression wave signals, obtaining the pure electrical signal generated by shear waves. Since the compression wave velocity of all geological soils is generally greater than the shear wave velocity, the compression wave signal arrives preferentially before the shear wave signal. This invention can filter out the compression wave signal, obtaining the pure, true electrical signal generated by shear waves, thereby enabling analysis to determine the shear wave velocity of the geological soil. Therefore, this invention solves the problem of existing technologies' difficulty in testing the shear wave velocity of 5-8 types of geological soils. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of a bridge-type acoustic transducer provided in an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the compensation circuit provided in an embodiment of the present invention;

[0035] Figure 3 This is one of the signal waveform diagrams provided in the embodiments of the present invention;

[0036] Figure 4 This is the second schematic diagram of the signal waveform provided in the embodiment of the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0038] This invention provides a bridge-type acoustic transducer for testing the compression and shear wave velocities of geological soil, such as... Figure 1 As shown, the bridge-type acoustic transducer includes a control circuit 1 and a piezoelectric ceramic module 2 encapsulated in a housing 5. The piezoelectric ceramic module 2 is electrically connected to the control circuit 1. The piezoelectric ceramic module 2 includes four piezoelectric ceramic tubes, such as... Figure 2 As shown, C1, C2, C3, and C4 are four piezoelectric ceramic tubes connected by a bridge circuit.

[0039] When testing the compressed wave, the control circuit sends the first test signal to C1, C2, C3, and C4, so that the waveforms of the compressed wave signals emitted by C1, C2, C3, and C4 remain synchronized and in the same direction.

[0040] During the shear wave test, the control circuit sends a second test signal to C1, C2, C3, and C4, causing the waveforms of the compressed wave signals emitted by C1 and C2 to remain synchronously reversed, the waveforms of the compressed wave signals emitted by C3 and C4 to remain synchronously reversed, the waveforms of the compressed wave signals emitted by C1 and C3 to remain synchronously in the same direction, and the waveforms of the compressed wave signals emitted by C2 and C4 to remain synchronously in the same direction; simultaneously, the waveforms of the shear wave signals emitted by C1, C2, C3, and C4 to remain synchronously in the same direction.

[0041] Specifically, in the actual testing process, the bridge acoustic transducer includes a first bridge acoustic transducer installed at the transmitting end and a second bridge acoustic transducer installed at the receiving end.

[0042] During the compression wave test, at the transmitting end, the control circuit in the first bridge acoustic transducer sends a first test signal to C1, C2, C3, and C4 in the first bridge acoustic transducer, causing the waveforms of the compression wave signals emitted by C1, C2, C3, and C4 in the first bridge acoustic transducer to remain synchronized and in the same direction, as shown in the waveform... Figure 3 As shown. Here, two or four piezoelectric ceramic tubes can be used as needed, so that the transmitted signal is several times that of a single piezoelectric ceramic tube (2 times when two piezoelectric ceramic tubes are connected, and 4 times when four piezoelectric ceramic tubes are connected).

[0043] At the receiving end, the waveforms of the compressed wave signals received by C1, C2, C3, and C4 in the second bridge acoustic transducer remain synchronized and in the same direction, such as... Figure 3 As shown. Here, two or four piezoelectric ceramic tubes can be used as needed, so that the received signal is several times that of a single piezoelectric ceramic tube (2 times when two piezoelectric ceramic tubes are connected, and 4 times when four piezoelectric ceramic tubes are connected).

[0044] When a piezoelectric ceramic tube is excited, it generates both compression waves and shear waves.

[0045] When testing shear waves, since the wave velocity of compression waves is greater than that of shear waves, it is necessary to eliminate the influence of compression waves. This invention employs... Figure 2 The bridge compensation circuit shown can effectively eliminate the effects of compressed waves.

[0046] At the transmitting end, the control circuit in the first bridge acoustic transducer sends a second test signal to C1, C2, C3, and C4 in the first bridge acoustic transducer, causing the waveforms of the compressed wave signals emitted by C1 and C2 in the first bridge acoustic transducer to remain synchronously reversed, the waveforms of the compressed wave signals emitted by C3 and C4 to remain synchronously reversed, the waveforms of the compressed wave signals emitted by C1 and C3 to remain synchronously in the same direction, and the waveforms of the compressed wave signals emitted by C2 and C4 to remain synchronously in the same direction. Figure 4 As shown in the diagram, after this superposition, the transmitted compressed wave signal is suppressed into a straight line.

[0047] Simultaneously, the waveforms of the shear wave signals emitted by C1, C2, C3, and C4 in the first bridge acoustic transducer remain synchronized and in the same direction, such as... Figure 3 As shown. In this way, the emitted shear wave signal will be amplified four times compared to a single piezoelectric ceramic tube.

[0048] At the receiving end, the waveforms of the compressed wave signals received by C1, C2, C3, and C4 in the second bridge acoustic transducer remain synchronously reversed; the waveforms of the compressed wave signals received by C3 and C4 remain synchronously reversed; the waveforms of the compressed wave signals received by C1 and C3 remain synchronously in the same direction; and the waveforms of the compressed wave signals received by C2 and C4 remain synchronously in the same direction. Figure 4 As shown in the figure. After this superposition, the received compressed wave signal is suppressed into a straight line.

[0049] Simultaneously, the waveforms of the shear wave signals received by C1, C2, C3, and C4 in the second bridge acoustic transducer remain synchronized and in the same direction, such as... Figure 3 As shown. In this way, the received shear wave signal will be amplified four times compared to a single piezoelectric ceramic tube.

[0050] Therefore, this invention, through the design of a bridge compensation circuit, amplifies both the transmitted and received compression wave signal intensity by 2-4 times when testing compression waves. When testing shear waves, both the transmitted and received compression wave signals are suppressed, while the transmitted and received shear wave signal intensity is amplified by 2-4 times. This solves the problem of existing technologies being unable to test the compression wave velocity of soil types 1-4 and the shear wave velocity of soil types 5-8.

[0051] Furthermore, such as Figure 1 As shown, a cable 3 is installed in the middle of the bridge-type acoustic transducer. Multiple wires branch off from the cable 3 and are connected to the positive and negative terminals of C1, C2, C3, and C4 respectively. The cable 3 is wrapped with a sealing rubber sleeve 4.

[0052] Furthermore, the housing 5 of the bridge-type acoustic transducer is a carbon fiber tube, and a prestressed glass fiber ribbon 6 is provided between adjacent piezoelectric ceramic tubes in the piezoelectric ceramic module 2. A primary adhesive layer 7 is provided on the outside of the piezoelectric ceramic module 2, and a secondary adhesive layer 8 is provided between the primary adhesive layer 7 and the housing 5.

[0053] Furthermore, a centralizer 9 and a counterweight head 10 are provided at the tail end of the bridge-type acoustic transducer.

[0054] In embodiments of the present invention, such as Figure 2 As shown, the control circuit 1 includes a positive voltage input terminal V+, a negative voltage input terminal V-, and four signal output terminals V. out1 Vout2 V out3 V out4 The four signal output terminals output corresponding test signals to the four piezoelectric ceramic tubes C1, C2, C3, and C4, respectively.

[0055] It should be noted that the first test signal mentioned above includes the corresponding test signals output from the four signal output terminals to the four piezoelectric ceramic tubes C1, C2, C3, and C4 respectively when testing the compression wave, and the second test signal includes the corresponding test signals output from the four signal output terminals to the four piezoelectric ceramic tubes C1, C2, C3, and C4 respectively when testing the shear wave.

[0056] The specific process for testing using the bridge-type acoustic transducer described in this invention is as follows:

[0057] The first step is to drill holes at the test site. The distance between the two test holes should be 1-3 meters, the hole diameter should be 75-100 mm, and the drilling depth should be determined according to the exploration requirements. The holes should be filled with water (clean water) with a density not exceeding 1.15 g / cm³. 3 ;

[0058] The second step is to place the first bridge-type acoustic transducer in a test borehole, with one end of the first bridge-type acoustic transducer connected to the transmitting end of the non-metallic ultrasonic instrument host; and to place the second bridge-type acoustic transducer in another test borehole, with one end of the second bridge-type acoustic transducer connected to the receiving end of the non-metallic ultrasonic instrument host.

[0059] The third step is to start the test. The non-metallic ultrasonic instrument host sends an electrical signal to the first bridge acoustic transducer. The control system of the non-metallic ultrasonic instrument host controls the high-voltage transmitting module to send a set of electrical signals with a frequency between 5KHz and 300KHz.

[0060] The fourth step involves the electrical signal being controlled by the control circuit. Based on the test compression wave or shear wave, the circuit sends corresponding first or second control signals to C1, C2, C3, and C4. In this way, the electrical signal is converted into an acoustic signal after passing through the first bridge acoustic transducer. The acoustic signal penetrates the tested soil and reaches the second bridge acoustic transducer.

[0061] Fifth step: After the second bridge acoustic transducer collects the acoustic signal, the control system of the non-metallic ultrasonic instrument host processes the acoustic signals received by C1, C2, C3 and C4 respectively, and obtains the complete electrical signal through the control circuit.

[0062] The sixth step involves the non-metallic ultrasonic instrument host analyzing the obtained electrical signals and processing them with specialized software (such as non-metallic ultrasonic processing and analysis software) to obtain the acoustic parameters of the tested geological soil: compression wave velocity or shear wave velocity.

[0063] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0064] The use of terms such as "an embodiment," "an embodiment," "an exemplary embodiment," and "some embodiments" in the specification indicates that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments (whether explicitly described or not) should be within the knowledge of those skilled in the art.

[0065] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. A and B can be singular or plural. Additionally, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects, but it can also represent an "and / or" relationship. Please refer to the context for a more accurate understanding.

[0066] In this invention, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of a single item or a plurality of items. For example, at least one of a, b, or c can represent: a, b, c, ab, ac, bc, or abc, where a, b, and c can be a single item or multiple items.

[0067] It should be understood that, in various embodiments of the present invention, the order of the above-mentioned process numbers does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0068] In the several embodiments provided by this invention, it should be understood that the disclosed devices, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0069] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0070] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0071] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0072] This invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this invention. To provide the public with a thorough understanding of this invention, specific details are described in detail in the following preferred embodiments; however, those skilled in the art will fully understand the invention even without these details. Furthermore, to avoid unnecessary misunderstanding of the essence of this invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A bridge-type acoustic transducer for testing the compression wave and shear wave velocities of geological soil, characterized in that, The bridge-type acoustic transducer includes a control circuit and a piezoelectric ceramic module encapsulated in a housing. The piezoelectric ceramic module is electrically connected to the control circuit. The piezoelectric ceramic module includes four piezoelectric ceramic tubes, namely C1, C2, C3 and C4, which are connected by a bridge circuit. When testing the compressed wave, the control circuit sends a first test signal to C1, C2, C3 and C4, so that the waveforms of the compressed wave signals emitted by C1, C2, C3 and C4 remain synchronized and in the same direction; During the shear wave test, the control circuit sends a second test signal to C1, C2, C3, and C4, causing the waveforms of the compressed wave signals emitted by C1 and C2 to remain synchronously reversed, the waveforms of the compressed wave signals emitted by C3 and C4 to remain synchronously reversed, the waveforms of the compressed wave signals emitted by C1 and C3 to remain synchronously in the same direction, and the waveforms of the compressed wave signals emitted by C2 and C4 to remain synchronously in the same direction; simultaneously, the waveforms of the shear wave signals emitted by C1, C2, C3, and C4 to remain synchronously in the same direction.

2. The bridge-type acoustic transducer according to claim 1, characterized in that, The bridge acoustic transducer includes a first bridge acoustic transducer installed at the transmitting end and a second bridge acoustic transducer installed at the receiving end. When testing the compressed wave, at the transmitting end, the control circuit in the first bridge acoustic transducer sends a first test signal to C1, C2, C3 and C4 in the first bridge acoustic transducer, so that the waveforms of the compressed wave signals emitted by C1, C2, C3 and C4 in the first bridge acoustic transducer remain synchronous and in the same direction; At the receiving end, the waveforms of the compressed wave signals received by C1, C2, C3 and C4 in the second bridge acoustic transducer remain synchronized and in the same direction; During shear wave testing, at the transmitting end, the control circuit in the first bridge acoustic transducer sends a second test signal to C1, C2, C3, and C4 in the first bridge acoustic transducer, causing the waveforms of the compressed wave signals emitted by C1 and C2 in the first bridge acoustic transducer to remain synchronously reversed, the waveforms of the compressed wave signals emitted by C3 and C4 to remain synchronously reversed, the waveforms of the compressed wave signals emitted by C1 and C3 to remain synchronously in the same direction, and the waveforms of the compressed wave signals emitted by C2 and C4 to remain synchronously in the same direction; simultaneously, the waveforms of the shear wave signals emitted by C1, C2, C3, and C4 in the first bridge acoustic transducer remain synchronously in the same direction. At the receiving end, the waveforms of the compressed wave signals received by C1, C2, C3 and C4 in the second bridge acoustic transducer remain synchronously reversed; the waveforms of the compressed wave signals received by C3 and C4 remain synchronously reversed; the waveforms of the compressed wave signals received by C1 and C3 remain synchronously in the same direction; and the waveforms of the compressed wave signals received by C2 and C4 remain synchronously in the same direction. At the same time, the waveforms of the shear wave signals received by C1, C2, C3 and C4 in the second bridge acoustic transducer remain synchronously in the same direction.

3. The bridge-type acoustic transducer according to claim 1, characterized in that, The bridge-type acoustic transducer has a cable in the middle, and the cable branches out into multiple conductors that are respectively connected to the positive and negative terminals of C1, C2, C3 and C4. The cable is wrapped with a sealing rubber sleeve.

4. The bridge-type acoustic transducer according to claim 1, characterized in that, The housing of the bridge-type acoustic transducer is a carbon fiber tube.

5. The bridge-type acoustic transducer according to claim 1, characterized in that, In the piezoelectric ceramic module, prestressed glass fiber ribbons are arranged between adjacent piezoelectric ceramic tubes.

6. The bridge-type acoustic transducer according to claim 1, characterized in that, A primary adhesive layer is provided on the outside of the piezoelectric ceramic module, and a secondary adhesive layer is provided between the primary adhesive layer and the shell.

7. The bridge-type acoustic transducer according to claim 1, characterized in that, The bridge-type acoustic transducer is equipped with a centralizer and a counterweight at its tail.

8. The bridge-type acoustic transducer according to claim 1, characterized in that, The control circuit includes a positive voltage input terminal, a negative voltage input terminal, and four signal output terminals. The four signal output terminals respectively output corresponding test signals to the four piezoelectric ceramic tubes C1, C2, C3, and C4.

9. The bridge-type acoustic transducer according to claim 1, characterized in that, The bridge-type acoustic transducer includes a first bridge-type acoustic transducer installed at the transmitting end and a second bridge-type acoustic transducer installed at the receiving end; the specific testing process is as follows: The first step is to drill holes at the test site. The distance between the two test holes should be 1-3 meters, the diameter of the holes should be 75-100mm, and the drilling depth should be set according to the exploration requirements. The holes should be filled with water with a density not greater than 1.15g / cm³. The second step is to place the first bridge-type acoustic transducer in a test borehole, with one end of the first bridge-type acoustic transducer connected to the transmitting end of the non-metallic ultrasonic instrument host; and to place the second bridge-type acoustic transducer in another test borehole, with one end of the second bridge-type acoustic transducer connected to the receiving end of the non-metallic ultrasonic instrument host. The third step is to start the test. The non-metallic ultrasonic instrument host sends an electrical signal to the first bridge acoustic transducer. The control system of the non-metallic ultrasonic instrument host controls the high-voltage transmitting module to send a set of electrical signals with a frequency between 5KHz and 300KHz. The fourth step involves the electrical signal being controlled by the control circuit. Based on the test compression wave or shear wave, corresponding first or second control signals are sent to C1, C2, C3, and C4. In this way, the electrical signal is converted into an acoustic signal after passing through the first bridge acoustic transducer. The acoustic signal penetrates the tested soil and reaches the second bridge acoustic transducer. Fifth step: After the second bridge acoustic transducer collects the acoustic signal, the control system of the non-metallic ultrasonic instrument host processes the acoustic signals received by C1, C2, C3 and C4 respectively, and obtains the complete electrical signal through the control circuit. The sixth step involves the non-metallic ultrasonic instrument host analyzing the obtained electrical signals to obtain the acoustic parameters of the tested geological soil: compression wave velocity or shear wave velocity.

Images