阅读说明：本技术 桩底岩溶探测方法、装置及系统、电子设备及存储介质 (Pile bottom karst detection method, device and system, electronic equipment and storage medium ) 是由 刘铁 化希瑞 张邦 刘铁华 赵威 赵晓博 段圣龙 刘剑 雷理 刘伟 汪文刚 陈 于 2020-11-30 设计创作，主要内容包括：本申请实施例公开了一种桩底岩溶探测方法、装置及系统、电子设备及存储介质。所述桩底岩溶探测方法可包括：获取相控阵列中第一方向的接收单元接收到的探测信号；获取所述相控阵列中第二方向的接收单元接收到的探测信号；所述第二方向与所述第一方向垂直；获取所述探测信号从发射单元到桩底并从所述桩底传输到对应的接收单元的传播时长；根据所述探测信号到达所述接收单元的幅值和所述传播时长,确定所述桩底岩溶的探测结果。如此,基于高覆盖的探测数据采集,实现对桩底岩溶情况的精准探测。(The embodiment of the application discloses a pile bottom karst detection method, a device and a system, electronic equipment and a storage medium. The pile bottom karst detection method can comprise the following steps: acquiring a detection signal received by a receiving unit in a first direction in a phased array; acquiring a detection signal received by a receiving unit in a second direction in the phased array; the second direction is perpendicular to the first direction; acquiring the propagation time of the detection signal from a transmitting unit to the pile bottom and from the pile bottom to a corresponding receiving unit; and determining the detection result of the pile bottom karst according to the amplitude of the detection signal reaching the receiving unit and the propagation time. So, based on the survey data acquisition of high coverage, realize the accurate detection to the pile bottom karst condition.)

1. A method of pile bottom karst detection, the method comprising:

acquiring a detection signal received by a receiving unit in a first direction in a phased array;

acquiring a detection signal received by a receiving unit in a second direction in the phased array; the second direction is perpendicular to the first direction;

acquiring the propagation time of the detection signal from a transmitting unit to the pile bottom and from the pile bottom to a corresponding receiving unit;

and determining the detection result of the pile bottom karst according to the amplitude of the detection signal reaching the receiving unit and the propagation time.

2. The method of claim 1, wherein prior to acquiring the probe signals received by the receiving units in the first direction in the phased array, the method further comprises:

sending a first transmit instruction to the phased array; the first transmitting instruction is used for instructing a transmitting unit to sequentially transmit a plurality of test signals; the emission speeds of the plurality of test signals are sequentially increased progressively according to a preset threshold value;

superposing the signals received by each receiving unit after the test signals are transmitted each time;

determining the corresponding transmission speed as a propagation speed according to the maximum value in the superposed signal amplitude; and the propagation speed is used for acquiring the propagation time length.

3. The method of claim 1, further comprising:

sending a second transmit instruction to the phased array; and the second transmitting instruction is used for indicating the plurality of transmitting units to sequentially transmit the detection signals for the receiving unit to receive, wherein after the nth transmitting unit transmits the preset time interval of the detection signals, the (n + 1) th transmitting unit transmits the detection signals.

4. The method of claim 3, further comprising:

and correlating the received signal acquired by the receiving unit with the signal sequence of the detection signal, and acquiring the detection signal received by the receiving unit from the received signal.

5. The method of claim 2, wherein said obtaining a propagation duration of said probe signal from a transmitting unit to a pile bottom and from said pile bottom to a corresponding receiving unit comprises:

acquiring the propagation distance of the detection signal from a transmitting unit to a pile bottom and from the pile bottom to a corresponding receiving unit;

and acquiring the propagation time of the detection signal from the transmitting unit to the pile bottom and from the pile bottom to the corresponding receiving unit according to the propagation speed and the propagation distance.

6. The method of claim 3, further comprising:

determining the time for each receiving unit corresponding to the transmitting unit to receive the direct signal according to the propagation speed; the direct signals are: the detection signal is a signal which is directly transmitted to the receiving unit from a transmitting unit without passing through the pile bottom;

and filtering the direct signals in the related signal sequence according to the propagation time length of the received direct signals or the arrival time of the received direct signals reaching the receiving unit.

7. The method of claim 6, wherein determining the detection result of the bedrock solution according to the amplitude of the detection signal reaching the receiving unit and the propagation time comprises:

and determining the detection result of the pile bottom karst according to the amplitude value of the detection signal reaching the receiving unit after the direct signal is filtered and the propagation time length.

8. A pile bottom karst detecting apparatus, the apparatus comprising:

the acquisition module is used for acquiring the detection signal received by the receiving unit in the first direction in the phased array; acquiring a detection signal received by a receiving unit in a second direction in the phased array; the second direction is perpendicular to the first direction; acquiring the propagation time of the detection signal from a transmitting unit to the pile bottom and from the pile bottom to a corresponding receiving unit;

and the determining module is used for determining the detection result of the pile bottom karst according to the amplitude of the detection signal reaching the receiving unit and the propagation time.

9. The apparatus of claim 8, further comprising:

a transmit module to transmit a first transmit instruction to the phased array; the first transmitting instruction is used for instructing a transmitting unit to sequentially transmit a plurality of test signals; the emission speeds of the plurality of test signals are sequentially increased progressively according to a preset threshold value;

the superposition module is used for superposing the signals received by the receiving units after the test signals are transmitted each time;

the determining module is further configured to:

determining the corresponding transmission speed as a propagation speed according to the maximum value in the superposed signal amplitude; and the propagation speed is used for acquiring the propagation time length.

10. The apparatus of claim 8, wherein the sending module is further configured to:

sending a second transmit instruction to the phased array; and the second transmitting instruction is used for indicating the plurality of transmitting units to sequentially transmit the detection signals for the receiving unit to receive, wherein after the nth transmitting unit transmits the preset time interval of the detection signals, the (n + 1) th transmitting unit transmits the detection signals.

11. The apparatus of claim 10, further comprising:

and a correlation module, configured to correlate the received signal obtained by the receiving unit with the signal sequence of the probe signal, and obtain the probe signal received by the receiving unit from the received signal.

12. The apparatus of claim 9, wherein the obtaining module is specifically configured to:

acquiring the propagation distance of the detection signal from a transmitting unit to a pile bottom and from the pile bottom to a corresponding receiving unit;

and acquiring the propagation time of the detection signal from the transmitting unit to the pile bottom and from the pile bottom to the corresponding receiving unit according to the propagation speed and the propagation distance.

13. The apparatus of claim 10, wherein the determining module is further configured to:

determining the time for each receiving unit corresponding to the transmitting unit to receive the direct signal according to the propagation speed; the direct signals are: the detection signal is a signal which is directly transmitted to the receiving unit from a transmitting unit without passing through the pile bottom;

the device further comprises:

and the filtering module is used for filtering the direct signals in the related signal sequence according to the propagation time of the received direct signals or the arrival time of the received direct signals reaching the receiving unit.

14. The apparatus of claim 13, wherein the determining module is specifically configured to:

and determining the detection result of the pile bottom karst according to the amplitude value of the detection signal reaching the receiving unit after the direct signal is filtered and the propagation time length.

15. A pile bottom karst detection system, the system comprising:

a phased array, comprising: a plurality of sensors; the sensors are respectively distributed in a first direction and a second direction in an arrayed manner; the second direction is perpendicular to the first direction;

a controller, which is wirelessly connected with each sensor of the phased array and is used for acquiring the detection signal received by the receiving unit in the first direction in the phased array; acquiring a detection signal received by a receiving unit in a second direction in the phased array; acquiring the propagation time of the detection signal from a transmitting unit to the pile bottom and from the pile bottom to a corresponding receiving unit; and determining the detection result of the pile bottom karst according to the amplitude of the detection signal reaching the receiving unit and the propagation time.

16. The system of claim 15, wherein the phased array comprises:

a transmit array, comprising: a plurality of emission sensors;

a receive array comprising: a plurality of receiving sensors;

wherein one of the transmitting sensors and one of the receiving sensors are integrally provided.

17. The system of claim 16,

the phased array includes: a sensor having a function of detecting signal transmission and reception.

18. The system of claim 17, wherein the sensor comprises:

an ultrasonic sensor for transmitting and receiving an ultrasonic signal as a probe signal.

19. The system of claim 15, wherein the phased array comprises at least:

a rectangular array;

or a circular array.

20. An electronic device, characterized in that the electronic device comprises: a processor and a memory for storing a computer program capable of running on the processor; wherein the content of the first and second substances,

the processor, when executing the computer program, performs the steps of the method of pile bottom karst detection according to any one of claims 1 to 7.

21. A computer-readable storage medium having stored thereon computer-executable instructions; the computer-executable instructions, when executed by a processor, enable the method of pile bottom karst detection according to any one of claims 1 to 7.

Technical Field

The invention relates to the field of geotechnical engineering investigation, in particular to a method, a device and a system for detecting a pile bottom karst, electronic equipment and a storage medium.

Background

The detection target of the pile bottom karst is mainly the karst hidden in bedrock, the size and the spatial development range of the karst are extremely complex, and the spatial range of the karst is difficult to be detected by point-to-surface in the aspect of plane distribution, so that adverse conditions such as half rock embedding of a pile foundation in the actual construction process are possibly caused. The existing pile bottom karst detection method mainly comprises an advanced drilling method, a tube wave detection method and a cross-hole elastic wave method. The single advanced drilling is easy to miss judgment of karst, and the drilling is increased, so that the construction period is greatly influenced. The vertical distribution range of karst in the rock mass in the drilling radius 1m can be surveyed to the pipe wave detection method, has higher vertical precision, but the detection result does not have the directive property, can't instruct peripor karst, broken unusual spatial distribution. The cross-hole elastic wave method is used for reconstructing the internal structure of the geologic body through tomography by observing the travel time, the energy (amplitude), the waveform and the like of seismic waves when the seismic waves pass through the geologic body, and has higher detection precision. However, in the karst area, the detectors cannot be effectively coupled when well fluid leaks from the hole, so that the method cannot be implemented. The exploration method in the construction stage mainly comprises a geological radar method and a sound wave reflection method. The geological radar method carries out geological radar data acquisition by arranging an annular or cross section at the bottom of the pile, but is limited by the detection area and depth of a field and only suitable for manual hole digging pile detection. The acoustic reflection method is characterized in that an energy converter is arranged at the bottom of the pile, and ultrasonic waves are excited and received by coupling of slurry to detect the development condition of a karst at the bottom of the pile.

Disclosure of Invention

In view of this, embodiments of the present invention provide a method, an apparatus, and a system for detecting a bottom karst of a pile, an electronic device, and a storage medium.

The technical scheme of the invention is realized as follows:

in a first aspect, an embodiment of the present invention provides a method for detecting a pile bottom karst, including:

acquiring a detection signal received by a receiving unit in a first direction in a phased array;

acquiring a detection signal received by a receiving unit in a second direction in the phased array; the second direction is perpendicular to the first direction;

acquiring the propagation time of a detection signal from a transmitting unit to the pile bottom and from the pile bottom to a corresponding receiving unit;

and determining the detection result of the pile bottom karst according to the amplitude of the detection signal reaching the receiving unit and the propagation time.

Further, before acquiring the probe signal received by the receiving unit in the first direction in the phased array, the method further includes:

sending a first transmit instruction to the phased array; the first transmitting instruction is used for instructing the transmitting unit to sequentially transmit a plurality of test signals; the emission speeds of the plurality of test signals are sequentially increased progressively according to a preset threshold;

superposing the signals received by each receiving unit after the test signals are transmitted each time;

determining the corresponding transmission speed as a propagation speed according to the maximum value in the superposed signal amplitude; and the propagation speed is used for acquiring the propagation time length.

Further, the method further comprises:

sending a second transmit instruction to the phased array; and the second transmitting instruction is used for indicating the plurality of transmitting units to sequentially transmit the detection signals for the receiving unit to receive, wherein the n +1 transmitting unit transmits the detection signals after the preset time interval that the nth transmitting unit transmits the detection signals.

Further, the method further comprises:

and correlating the received signal acquired by the receiving unit with the signal sequence of the detection signal, and acquiring the detection signal received by the receiving unit from the received signal.

Further, acquiring the propagation duration of the detection signal from the transmitting unit to the pile bottom and from the pile bottom to the corresponding receiving unit, includes:

acquiring the propagation distances of the detection signals from the transmitting unit to the pile bottom and from the pile bottom to the corresponding receiving unit;

and acquiring the propagation time of the detection signal from the transmitting unit to the pile bottom and from the pile bottom to the corresponding receiving unit according to the propagation speed and the propagation distance.

Further, the method further comprises:

determining the time for each receiving unit corresponding to the transmitting unit to receive the direct signal according to the propagation speed; the direct signal is: detecting signals which are directly transmitted to a receiving unit from a transmitting unit without passing through the pile bottom in the signals;

and filtering the direct signal in the related signal sequence according to the propagation time length of the received direct signal or the arrival time of the received direct signal reaching the receiving unit.

Further, determining a detection result of the pile bottom karst according to the amplitude and the propagation time of the detection signal reaching the receiving unit, including:

and determining the detection result of the pile bottom karst according to the amplitude and the propagation time of the detection signal reaching the receiving unit after the direct signal is filtered.

In a second aspect, an embodiment of the present invention provides a pile bottom karst detecting apparatus, including:

the acquisition module is used for acquiring the detection signal received by the receiving unit in the first direction in the phased array; acquiring a detection signal received by a receiving unit in a second direction in the phased array; the second direction is perpendicular to the first direction; acquiring the propagation time of a detection signal from a transmitting unit to the pile bottom and from the pile bottom to a corresponding receiving unit;

and the determining module is used for determining the detection result of the pile bottom karst according to the amplitude and the propagation time of the detection signal reaching the receiving unit.

Further, the apparatus further comprises:

a sending module for sending a first sending instruction to the phased array; the first transmitting instruction is used for instructing the transmitting unit to sequentially transmit a plurality of test signals; the emission speeds of the plurality of test signals are sequentially increased progressively according to a preset threshold;

the superposition module is used for superposing the signals received by the receiving units after the test signals are transmitted each time;

the determining module is further configured to:

determining the corresponding transmission speed as a propagation speed according to the maximum value in the superposed signal amplitude; and the propagation speed is used for acquiring the propagation time length.

Further, the sending module is further configured to:

sending a second transmit instruction to the phased array; and the second transmitting instruction is used for indicating the plurality of transmitting units to sequentially transmit the detection signals for the receiving unit to receive, wherein the n +1 transmitting unit transmits the detection signals after the preset time interval that the nth transmitting unit transmits the detection signals.

Further, the apparatus further comprises:

and the correlation module is used for correlating the received signal acquired by the receiving unit with the signal sequence of the detection signal and acquiring the detection signal received by the receiving unit from the received signal.

Further, the obtaining module is specifically configured to:

acquiring the propagation distances of the detection signals from the transmitting unit to the pile bottom and from the pile bottom to the corresponding receiving unit;

and acquiring the propagation time of the detection signal from the transmitting unit to the pile bottom and from the pile bottom to the corresponding receiving unit according to the propagation speed and the propagation distance.

Further, the determining module is further configured to:

determining the time for each receiving unit corresponding to the transmitting unit to receive the direct signal according to the propagation speed; the direct signal is: detecting signals which are directly transmitted to a receiving unit from a transmitting unit without passing through the pile bottom in the signals;

the device further comprises:

and the filtering module is used for filtering the direct signal in the related signal sequence according to the propagation time length of the received direct signal or the arrival time of the received direct signal reaching the receiving unit.

Further, the determining module is specifically configured to:

and determining the detection result of the pile bottom karst according to the amplitude and the propagation time of the detection signal reaching the receiving unit after the direct signal is filtered.

In a third aspect, an embodiment of the present invention provides a pile bottom karst detecting system, including:

a phased array, comprising: a plurality of sensors; the sensors are respectively distributed in a first direction and a second direction in an arrayed manner; the second direction is perpendicular to the first direction;

the controller is in wireless connection with each sensor of the phased array and used for acquiring the detection signal received by the receiving unit in the first direction in the phased array; acquiring a detection signal received by a receiving unit in a second direction in the phased array; acquiring the propagation time of a detection signal from a transmitting unit to the pile bottom and from the pile bottom to a corresponding receiving unit; and determining the detection result of the pile bottom karst according to the amplitude and the propagation time of the detection signal reaching the receiving unit.

Further, the phased array includes:

a transmit array, comprising: a plurality of emission sensors;

a receive array comprising: a plurality of receiving sensors; wherein, a transmitting sensor and a receiving sensor are integrated.

Further, the phased array includes: a sensor having a function of detecting signal transmission and reception.

Further, the sensor includes: an ultrasonic sensor for transmitting and receiving an ultrasonic signal as a probe signal.

Further, the phased array, at least comprising: a rectangular array; or a circular array.

In a fourth aspect, an embodiment of the present invention provides an electronic device, where the electronic device includes: a processor and a memory for storing a computer program capable of running on the processor;

the processor, when running said computer program, performs the steps of one or more of the preceding claims.

In a fifth aspect, an embodiment of the present invention provides a computer-readable storage medium, where the computer-readable storage medium stores computer-executable instructions; the computer-executable instructions, when executed by a processor, are capable of implementing the methods described in one or more of the preceding claims.

The pile bottom karst detection method provided by the invention comprises the steps of obtaining a detection signal received by a receiving unit in a first direction in a phased array; acquiring a detection signal received by a receiving unit in a second direction in the phased array; the second direction is perpendicular to the first direction; acquiring the propagation time of the detection signal from a transmitting unit to the pile bottom and from the pile bottom to a corresponding receiving unit; and determining the detection result of the pile bottom karst according to the amplitude of the detection signal reaching the receiving unit and the propagation time. So, based on the detection signal that phased array receiving element of two directions acquireed, can promote the detection coverage degree to the pile bottom karst, extended the radial detection scope in pile bottom greatly, make the detection result can embody the karst situation of developing of pile bottom wider, improve pile foundation security. The density of the reflected signals can be improved, a better covering effect is obtained on the basis of coverage range improvement, and the detection of the karst environment at the bottom of the pile is more careful and accurate. According to the propagation duration of the detection signals, the amplitude of the detection signals corresponding to each transmitting unit can be accurately determined in the detection signals received by the receiving unit, and then the condition of the karst at the bottom of the pile can be more accurately represented according to the detection results obtained at the bottom of the pile.

Drawings

Fig. 1 is a schematic flow chart of a method for detecting a pile bottom karst according to an embodiment of the present invention;

fig. 2 is a schematic flow chart of a method for detecting a pile bottom karst according to an embodiment of the present invention;

fig. 3 is a schematic flow chart of a method for detecting a pile bottom karst according to an embodiment of the present invention;

fig. 4 is a schematic flow chart of a method for detecting a pile bottom karst according to an embodiment of the present invention;

fig. 5 is a schematic flow chart of a method for detecting a pile bottom karst according to an embodiment of the present invention;

fig. 6 is a schematic flow chart of a method for detecting a pile bottom karst according to an embodiment of the present invention;

fig. 7 is a schematic flow chart of a method for detecting a pile bottom karst according to an embodiment of the present invention;

fig. 8 is a schematic structural diagram of a pile bottom karst detecting device according to an embodiment of the present invention;

fig. 9 is a schematic structural diagram of a pile bottom karst detection system according to an embodiment of the present invention;

fig. 10 is a schematic flow chart of a method for detecting a pile bottom karst according to an embodiment of the present invention;

fig. 11 is a schematic data acquisition diagram of a method for detecting a pile bottom karst according to an embodiment of the present invention;

fig. 12 is a schematic diagram of a signal-dependent waveform of a method for detecting a bottom karst according to an embodiment of the present invention;

FIG. 13 is a schematic diagram of a simulated wave field of a method for detecting a pile bottom karst according to an embodiment of the present invention;

fig. 14 is a schematic three-dimensional image of a method for detecting a pile bottom karst according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail with reference to the accompanying drawings, the described embodiments should not be construed as limiting the present invention, and all other embodiments obtained by a person of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In the following description, reference is made to "some embodiments" which describe a subset of all possible embodiments, but it is understood that "some embodiments" may be the same subset or different subsets of all possible embodiments, and may be combined with each other without conflict.

In the following description, references to the terms "first \ second \ third" are only to distinguish similar objects and do not denote a particular order, but rather the terms "first \ second \ third" are used to interchange specific orders or sequences, where appropriate, to enable embodiments of the invention described herein to be practiced in other than the order shown or described herein.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein is for the purpose of describing embodiments of the invention only and is not intended to be limiting of the invention.

As shown in fig. 1, an embodiment of the present invention provides a method for detecting a pile bottom karst, where the method includes:

s110: acquiring a detection signal received by a receiving unit in a first direction in a phased array;

s120: acquiring a detection signal received by a receiving unit in a second direction in the phased array; the second direction is perpendicular to the first direction;

s130: acquiring the propagation time of the detection signal from a transmitting unit to the pile bottom and from the pile bottom to a corresponding receiving unit;

s140: and determining the detection result of the pile bottom karst according to the amplitude of the detection signal reaching the receiving unit and the propagation time.

Here, the phased array includes a plurality of ultrasonic sensors, each of which can be used to both transmit and receive ultrasonic signals. Wherein, ultrasonic signals are excited and received by the sensor and used as detection signals for detecting the karst at the bottom of the pile. Alternatively, the plurality of ultrasonic sensors may be arranged at equal intervals, and the phased array may be formed in a one-dimensional linear arrangement manner, or may be formed in a two-dimensional rectangular manner, a two-dimensional circular manner, or the like. The preset encoding signal is a preset detection signal, and the encoding mode of the signal may be a pseudo-random encoding signal, or a frequency sweeping signal with gradually increasing or decreasing frequency.

In the embodiment of the invention, the phase control array is arranged on the plane of the pile bottom required to be subjected to karst detection, and the array arrangement mode can be selected according to the shape of the cross section of the pile bottom so as to cover a larger detection range of the pile bottom. For example, when the cross-section of the pile bottom is rectangular, a phased array with one-dimensional linearity or two-dimensional rectangle can be selected. All the sensors for receiving the acoustic wave signals, namely the detection signals received by the receiving unit, are acquired along two mutually perpendicular directions of the plane of the phased array in sequence. After the transmitting unit transmits the detection signal, all other sensors in the array are used as receiving units corresponding to the transmitting unit to receive the detection signal transmitted by the transmitting unit through pile bottom mud and reflected by the pile bottom bedrock.

In one embodiment, a two-dimensional rectangular phased array is arranged at the bottom of the pile, and a three-dimensional coordinate system is established based on the position relation of each unit in the phased array. Starting from one corner of the two-dimensional rectangular array, sequentially collecting detection signals received by each receiving unit along the X-axis direction according to the sequence of the unit coordinates. And after the acquisition is finished, repeating the acquisition process along the Y-axis direction. In a three-dimensional coordinate system, for a transmitting-receiving pair consisting of a transmitting unit and a receiving unit, the time length of a detection signal which is transmitted by the transmitting unit and then reflected and propagated through the pile bottom and received by the receiving unit is obtained. And then the amplitude of the acquired detection signal of each receiving unit can be determined by combining the propagation time length, the amplitude of the detection signal reaching the receiving unit after reflection propagation can be determined, and the detection result of the pile bottom karst can be determined by using the signal amplitude.

In another embodiment, a plurality of imaging points are arranged in a pile bottom area below the phased array based on a three-dimensional coordinate system, an imaging value is determined at each imaging point according to the detection result, the detection result of the pile bottom karst is obtained according to the imaging values of the imaging points, and a three-dimensional image model is established for the area where the imaging points are located according to the detection result. For each imaging point, acquiring the propagation time of the detection signal of each transceiving pair, including acquiring the propagation time Ts from the transmitting unit to the imaging point and the propagation time Tg from the imaging point to the receiving unit respectively. And starting from the moment when the transmitting unit transmits the detection signal, determining the signal amplitude corresponding to the moment Ts + Tg, and assigning the amplitude to the imaging value of the imaging point. And accumulating the imaging values of the received and transmitted detection signals corresponding to the imaging points to obtain the accumulated imaging value of the imaging points. According to the accumulated imaging values of all imaging points, a detection result of the pile bottom karst can be obtained, and then a corresponding pile bottom image model is generated based on a three-dimensional image model generation algorithm.

Therefore, signal acquisition is carried out along two directions of an X, Y axis of the phased array plane, signal reflection data facing different angles of a pile bottom area are obtained, and the detection range of the pile bottom is greatly expanded. And for the two-dimensional array, the position of the device does not need to be changed, the detection data with high coverage rate can be obtained by repeatedly collecting the data along two directions, the detection speed is higher, and the data collection efficiency is improved. Based on a plurality of ultrasonic sensors arranged in an array, high-precision three-dimensional imaging can be performed on the bottom karst of the pile through the coverage of high-density reflection data. The propagation time of the detection signal is determined according to the relative position relationship between the transceiver unit and the pile bottom, and the amplitude of the detection signal corresponding to each transceiver pair can be accurately determined under the condition that each receiver unit can receive the reflection signals of a plurality of transmitting units, so that a detection result capable of representing the condition of the karst of the pile bottom more accurately is obtained, and a three-dimensional image model can be accurately generated at the pile bottom.

In some embodiments, as shown in fig. 2, before the S110, the method further includes:

s101: sending a first transmit instruction to the phased array; the first transmitting instruction is used for instructing a transmitting unit to sequentially transmit a plurality of test signals; the emission speeds of the plurality of test signals are sequentially increased progressively according to a preset threshold value;

s102: superposing the signals received by each receiving unit after the test signals are transmitted each time;

s103: determining the corresponding transmission speed as a propagation speed according to the maximum value in the superposed signal amplitude; and the propagation speed is used for acquiring the propagation time length.

In the embodiment of the invention, a first transmitting instruction is sent to instruct the transmitting unit to transmit the test signal, all the other receiving units receive the test signal, and the propagation speed of the signal at the pile bottom is determined in a speed scanning mode. Preferably, the first transmit instruction instructs one of the ultrasonic sensors at one end of the phased array to transmit the test signal. For example, for a one-dimensional linear phased array, a sensor at one end is instructed to transmit; for a two-dimensional rectangular phased array, a sensor located at the apex of any of the four corners of the rectangular array may be instructed to transmit.

In one embodiment, the initial velocity V is preset₀Indicating one end of the arrayTransmitting unit at velocity V₀Transmitting test signals and obtaining the linear distance L from the transmitting unit to each receiving unit_iI is 1,2,3 …, calculating the receiving time t of the receiving unit_i＝L_i/V₀. Further acquiring the corresponding t of each receiving unit_iThe amplitude of the signals received at the moment are superposed to obtain V₀Corresponding amplitude sum A at speed₀. According to a preset speed increment dv, the same transmitting unit is instructed to rotate again at a speed V₁＝V₀+ dv sends a second test signal, V being obtained in the same way as described above₁Corresponding amplitude sum A at speed₁. By analogy, V_n＝V₀+ n + dv, obtaining V₀,V₁…V_nCorresponding A at speed₀，A₁…A_nUp to V_nReaching a preset maximum speed. Determination of A₀，A₁…A_nMaximum value of A_mThen A is_mCorresponding transmitting speed V_mIs the propagation speed of the signal at the bottom of the pile.

So, because pile bottom environment is complicated and the difference is great, the sound wave propagates and reflects through the bed rock of different materials in the mud of different density, and actual propagation velocity is diverse. By means of speed scanning of the test signals, the sensor array for detecting the karst can determine the speed of the signals propagating at the pile bottom based on the amplitude of the received signals, and the propagation speed does not need to be acquired through an additional speed detection device. The method can save resources, reduce the use of additional equipment, quickly acquire the propagation speed and improve the detection efficiency.

In some embodiments, as shown in fig. 3, the method further comprises:

s104: sending a second transmit instruction to the phased array; and the second transmitting instruction is used for indicating the plurality of transmitting units to sequentially transmit the detection signals for the receiving unit to receive, wherein after the nth transmitting unit transmits the preset time interval of the detection signals, the (n + 1) th transmitting unit transmits the detection signals.

In the embodiment of the invention, a second transmitting instruction is sent to instruct the sensors in the array for transmitting the acoustic wave signals, namely, the transmitting unit transmits the detection signals, and the detection signals are transmitted through the pile bottom and then are received by the receiving unit. Alternatively, the second transmission instruction may instruct one sensor unit to transmit, or may instruct a plurality of or all of the sensor units to transmit. And the time interval between the nth transmitting unit and the (n + 1) th transmitting unit for transmitting the detection signal is a preset value, wherein n is a positive integer greater than 0, and the preset time interval is determined by the phase angle of each transmitting unit in the phased array. The plurality of transmitting units sequentially transmit signals in an arranging order, for example, the transmitting units in the one-dimensional array may sequentially transmit signals in a sequence from left to right. The transmitting units in the two-dimensional rectangular array can transmit sequentially from left to right along the X-axis direction, and transmit sequentially from bottom to top along the Y-axis direction after the receiving signals of the receiving units are acquired.

Alternatively, the second transmission instruction may carry a predetermined code signal as the probe signal transmitted by the transmitting unit. For example, the predetermined code signal may be a pseudo-random code signal, or a frequency sweep signal with gradually increasing or decreasing frequency. And after receiving the second transmitting instruction, the transmitting unit transmits a preset coding signal for detection. Therefore, the seismic source coding design is carried out on the transmitting signal, so that the transmitting signal has the characteristic of being more suitable for pile bottom detection, the signal transmitting energy is increased through a specific coding mode, the anti-interference capability of data acquisition is improved, the obtained data has higher signal-to-noise ratio, and the detection depth can be effectively expanded.

In one embodiment, a second transmit command is sent to a two-dimensional rectangular phased array, with each cell in the array being equally spaced at a distance dx. The phase angles of the sensor units in the array are sequentially-Max theta to Max theta along the X-axis direction, and the phase angles are gradually increased according to the angle interval d theta. The propagation velocity determined by the velocity sweep is V, the predetermined time interval isThe second emission instruction indicates the emission units in the X-axis direction to sequentially emit preset emission according to preset time intervals dt from left to rightThe signal is encoded. And acquiring the detection signals received by all the receiving units, and after the acquisition is finished, indicating the transmitting units in the Y-axis direction to perform the transmitting and acquiring processes again according to the sequence from bottom to top.

In another embodiment, a second transmit command is sent to a one-dimensional linear phased array, with the equally spaced elements in the array being at a distance dx. The phase angle of each unit from left to right is sequentially from-Max theta to Max theta, and the phase angles are increased progressively according to the angle interval d theta. The propagation velocity determined by the velocity sweep is V, the predetermined time interval isAnd the second transmitting instruction instructs the transmitting unit to sequentially transmit signals at dt intervals from left to right and acquire the detection signals received by all the units. And after the acquisition is finished, rotating the whole one-dimensional linear array on the plane of the pile bottom by a rotation angle phi in a clockwise or anticlockwise direction, and repeating the transmitting and acquiring processes. The rotation angle phi continues until the array is rotated up to 180 deg..

Therefore, by controlling the excitation time delay of the transmitting unit in the array, the phased array can obtain a synthetic sound beam with higher signal intensity and stronger reliability in a multi-point excitation acquisition mode, and finally obtained detection data have higher signal-to-noise ratio. And the multi-transmission and multi-reception acquisition mode can realize high-density signal detection, so that the coverage of the detection data on the pile bottom area is more comprehensive and careful. In addition, the synthesis of the transmitted sound waves is controlled based on the time interval, the excitation time interval of each unit can be freely adjusted, the pointing direction of the main lobe of the synthesized sound beam can be adjusted, and the pile bottom areas at different angles can be accurately detected according to requirements.

In some embodiments, as shown in fig. 4, the method further comprises:

s121: and correlating the received signal acquired by the receiving unit with the signal sequence of the detection signal, and acquiring the detection signal received by the receiving unit from the received signal.

In the embodiment of the invention, the signal sequence received by each receiving unit is correlated with the transmitted detection signal sequence, so that the original detection signal can be obtained, and further shot gather records closer to the transmitted signal can be obtained. The shot gather records demodulation data of a plurality of seismic channels corresponding to each shot point (sound wave emission point), namely, in the embodiment of the invention, the shot gather records signals received by a plurality of receiving units corresponding to each emission unit. Here, the signal sequence of the signal acquired by the receiving unit and the probe signal may be subjected to time domain correlation processing or frequency domain correlation processing.

So, through the correlation with original detecting signal, can reduce the noise signal that mixes in the transmission route to detecting signal's influence, obtain the detecting signal sequence in the received signal that the receiving element acquireed, signal characteristic is more close to original detecting signal to realize the promotion of detection result precision.

In some embodiments, as shown in fig. 5, the S130 includes:

s131: acquiring the propagation distance of the detection signal from a transmitting unit to a pile bottom and from the pile bottom to a corresponding receiving unit;

s132: and acquiring the propagation time of the detection signal from the transmitting unit to the pile bottom and from the pile bottom to the corresponding receiving unit according to the propagation speed and the propagation distance.

In the embodiment of the invention, the propagation time of the detection signal from the transmitting unit to the receiving unit through the pile bottom can be determined according to the propagation distance from the transmitting unit to the area to be measured at the pile bottom, the propagation distance from the pile bottom to the corresponding receiving unit and the propagation speed of the pile bottom signal determined by the speed scanning method.

In one embodiment, in a three-dimensional coordinate system established based on the positions of the sensors of the pile bottom phased array, a plurality of imaging points are set in the area of the pile bottom, and then the propagation distance from the transmitting unit to the pile bottom imaging point and the propagation distance from the pile bottom imaging point to the corresponding receiving unit can be calculated according to the coordinates of the transmitting unit and the receiving unit of each transceiving pair in the coordinate system and the coordinates of the imaging points. And then according to the propagation distance and the determined propagation speed, the propagation time of the detection signal from the transmitting unit to the pile bottom and from the pile bottom to the corresponding receiving unit can be determined.

In another embodiment, an imaging spot is acquired to each of the firing cells S_iDistance R of_iI 1,2.3 …, the propagation time of the emitting unit to the imaging pointWherein dt_iIs based onAnd obtaining the preset time interval of the ith transmitting unit. Calculated for one imaging pointIn, take the minimum value T_s. For the propagation time T of the imaging point to the receiving unit_gCalculating the distance R from the imaging point to the receiving unit_gTo obtain T_g＝R_g/V。

Therefore, the propagation distances between the imaging points and the transmitting unit and between the imaging points and the receiving unit are determined based on the coordinate system, the trouble of manually measuring the distances at the pile bottom can be reduced, and the detection efficiency is improved. And then according to the propagation distance and the propagation speed, the propagation time of the detection signal from the transmitting unit to the receiving unit through the pile bottom imaging point can be determined, and the signal receiving time corresponding to each imaging point and each receiving unit can be accurately obtained so as to obtain the detection signal amplitude corresponding to the imaging point.

In some embodiments, as shown in fig. 6, the method further comprises:

s133: determining the time for each receiving unit corresponding to the transmitting unit to receive the direct signal according to the propagation speed; the direct signals are: the detection signal is a signal which is directly transmitted to the receiving unit from a transmitting unit without passing through the pile bottom;

s134: and filtering the direct signals in the related signal sequence according to the propagation time length of the received direct signals or the arrival time of the received direct signals reaching the receiving unit.

In the embodiment of the invention, after the signal is sent out by the transmitting unit, the signal is transmitted to the bedrock through the mud at the bottom of the pile to form reflection, and then is transmitted to the receiving unit through the mud, and is also directly transmitted to the receiving unit. The reflected signals are used for detecting the bottom karst of the pile, so that the direct waves directly received by the receiving unit without reflection need to be cut off. Through the determined signal propagation speed and the straight-line distance between the transmitting unit and the receiving unit, the propagation time of the sound wave signal transmitted by the transmitting unit directly reaching the receiving unit can be determined, and the time when the direct signal reaches the receiving unit can also be determined. And then, according to the information such as the phase position and the signal length of the detection signal transmitted by the transmitting unit, the signal recorded by the receiving unit at the corresponding direct signal receiving moment can be determined and filtered.

Therefore, the direct signal can be accurately positioned in the signal record of the receiving unit by the propagation time of the direct signal or the receiving time of the receiving unit to the direct signal. And the detection signals received by the receiving unit are filtered to obtain direct wave signals, so that the detection signals used for generating detection results are more accurate, the interference of invalid signals which cannot represent the development condition of the pile bottom karst is reduced, and the precision of detection data is improved.

In some embodiments, as shown in fig. 7, the S140 includes:

s141: and determining the detection result of the pile bottom karst according to the amplitude value of the detection signal reaching the receiving unit after the direct signal is filtered and the propagation time length.

In the embodiment of the invention, for each imaging point, the propagation time length T from the emission unit to the imaging point is acquired respectively_sAnd the propagation time T of the imaging point to the receiving unit_gObtaining the propagation time length T of the detection signal passing through the imaging point_s+T_g. After the detection signals received by the receiving units of each transceiving pair are correlated with the preset coding signals and direct signals are filtered, the moment when the transmitting units transmit the detection signals is taken as the starting moment, and finally the obtained signals are at T_s+T_gAnd assigning the signal amplitude value of the moment to the imaging value of the imaging point. And accumulating the imaging values of the received and transmitted detection signals corresponding to the imaging points to obtain the accumulated imaging value of the imaging points. And obtaining a detection result of the karst at the bottom of the pile according to the accumulated imaging values of all the imaging points. And generating a corresponding pile bottom three-dimensional image model based on a three-dimensional image model generation algorithm. Alternatively, the initial direction α of the array can be determined by using an electronic compass fixed on the phased array, the obtained three-dimensional image model is rotated by an angle α, and the final three-dimensional image model is corrected to the north (or east) direction.

Therefore, the signals received by the receiving unit are correlated with the transmitting signals, a correlated signal sequence closer to the transmitting signals is obtained, and the interference of noise signals mixed in the detection signals in the signal transmission process is reduced. And then the direct signals of the receiving unit are filtered, so that invalid detection signals which cannot represent the information of the karst at the bottom of the pile are further reduced, and the performance of the detection signals is improved. Based on the optimized signals and the determination of the propagation time, a more accurate detection result can be obtained, and the development condition of the karst at the bottom of the pile can be more truly restored based on the three-dimensional image model of the area at the bottom of the pile, which is obtained by the detection result, so that the detection precision is greatly improved.

As shown in fig. 8, an embodiment of the present invention provides a pile bottom karst detecting apparatus, including:

an obtaining module 110, configured to obtain a probe signal received by a receiving unit in a first direction in a phased array; acquiring a detection signal received by a receiving unit in a second direction in the phased array; the second direction is perpendicular to the first direction; acquiring the propagation time of the detection signal from a transmitting unit to the pile bottom and from the pile bottom to a corresponding receiving unit;

a determining module 120, configured to determine a detection result of the pile bottom karst according to the amplitude of the detection signal reaching the receiving unit and the propagation duration.

In some embodiments, the apparatus further comprises:

a sending module 130 for sending a first sending instruction to the phased array; the first transmitting instruction is used for instructing a transmitting unit to sequentially transmit a plurality of test signals; the emission speeds of the plurality of test signals are sequentially increased progressively according to a preset threshold value;

a superposition module 140, configured to superpose signals received by each receiving unit after transmitting the test signal each time;

the determining module 120 is further configured to:

determining the corresponding transmission speed as a propagation speed according to the maximum value in the superposed signal amplitude; and the propagation speed is used for acquiring the propagation time length.

In some embodiments, the sending module 130 is further configured to:

sending a second transmit instruction to the phased array; and the second transmitting instruction is used for indicating the plurality of transmitting units to sequentially transmit the detection signals for the receiving unit to receive, wherein after the nth transmitting unit transmits the preset time interval of the detection signals, the (n + 1) th transmitting unit transmits the detection signals.

In some embodiments, the apparatus further comprises:

a correlation module 150, configured to correlate the received signal obtained by the receiving unit with the signal sequence of the probe signal, and obtain the probe signal received by the receiving unit from the received signal.

In some embodiments, the obtaining module 110 is specifically configured to:

acquiring the propagation distance of the detection signal from a transmitting unit to a pile bottom and from the pile bottom to a corresponding receiving unit;

and acquiring the propagation time of the detection signal from the transmitting unit to the pile bottom and from the pile bottom to the corresponding receiving unit according to the propagation speed and the propagation distance.

In some embodiments, the determining module 120 is further configured to:

determining the time for each receiving unit corresponding to the transmitting unit to receive the direct signal according to the propagation speed; the direct signals are: the detection signal is a signal which is directly transmitted to the receiving unit from a transmitting unit without passing through the pile bottom;

the device further comprises:

a filtering module 160, configured to filter the direct signal in the relevant signal sequence according to the propagation duration of the received direct signal or the arrival time at the receiving unit.

In some embodiments, the determining module 120 is specifically configured to:

and determining the detection result of the pile bottom karst according to the amplitude value of the detection signal reaching the receiving unit after the direct signal is filtered and the propagation time length.

As shown in fig. 9, an embodiment of the present invention provides a pile bottom karst detection system, including:

a phased array 210, comprising: a plurality of sensors; the sensors are respectively distributed in a first direction and a second direction in an arrayed manner; the second direction is perpendicular to the first direction;

a controller 220, which establishes a wireless connection with each sensor of the phased array, and is used for acquiring the detection signal received by the receiving unit in the first direction in the phased array; acquiring a detection signal received by a receiving unit in a second direction in the phased array; acquiring the propagation time of the detection signal from a transmitting unit to the pile bottom and from the pile bottom to a corresponding receiving unit; and determining the detection result of the pile bottom karst according to the amplitude of the detection signal reaching the receiving unit and the propagation time.

In some embodiments, the phased array 210 includes:

a transmit array, comprising: a plurality of emission sensors;

a receive array comprising: a plurality of receiving sensors;

wherein one of the transmitting sensors and one of the receiving sensors are integrally provided.

In some embodiments, the phased array 210 includes: a sensor having a function of detecting signal transmission and reception.

In some embodiments, the sensor comprises:

an ultrasonic sensor for transmitting and receiving an ultrasonic signal as a probe signal.

In some embodiments, the phased array 210, includes at least:

a rectangular array;

or a circular array.

One specific example is provided below in connection with any of the embodiments described above:

as shown in fig. 9:

1) and (3) measuring point arrangement: and a plurality of sound wave transmitting and exciting sensors which are arranged at equal intervals in a one-dimensional linear, two-dimensional circular or two-dimensional matrix array are arranged at the bottom of the pile.

2) And (3) testing the speed: and (3) exciting one end of the array, and automatically calculating the acoustic velocity V in the bedrock through the velocity scanning mode on the records received by the other points.

3) Data acquisition: as shown in fig. 10, the transducer array elements excite the acoustic wave with a time delay, and all elements receive the acoustic wave signal at the same time. The pre-designed coded signal is used as an excitation signal of the transmitting unit, and the sensor array unit performs data acquisition according to a one-shot multi-receiving or multi-shot multi-receiving mode.

4) Data preprocessing: and calculating the coordinates of each arranged transceiver sensor, establishing an observation system, and denoising the acquired data. As shown in fig. 11, the signals collected by each unit are correlated using the transmit signals to obtain shot gather records resembling pulse excitations.

5) Direct wave ablation: according to the acoustic wave velocity V obtained by calculation in the step 2), calculating the arrival time of each recorded direct wave, setting the window length, and cutting off the direct acoustic wave signals propagated in the slurry.

6) Waveform imaging: as shown in fig. 12 and 13, three-dimensional imaging is performed by a method of returning and superimposing the waveform signals retained in 5) to the pile bottom imaging point.

7) And (3) direction correction: determining the orientation of the device and performing orientation correction on the result obtained in the step 6).

In the above technical solution, in the step 1), the distance between the detectors is dx, the number of the detectors is mxn (m, n >2), and each sensor has a function of exciting and receiving a sound wave.

In the above technical solution, in the step 2), in the process that the sound wave propagates from the excitation point to each receiving point, the propagation path of the sound wave is as follows: sensor-mud-bed rock-mud-sensor. One end excites the sound wave, and the other units receive signals. Given a velocity V0, the distance L from the excitation point to each receiving unit and the propagation time t equal to L/V0 are calculated, and the recordings at different times t in each unit recording are superimposed to obtain the amplitude a 0. And calculating Vi as V0+ dv according to the speed increment dv, and obtaining the corresponding amplitude Ai. And calculating to obtain Vi corresponding to the maximum Ai value, namely the propagation velocity V in the bedrock.

In the above technical solution, in the step 3), the encoding manner of the signal may be a frequency sweeping signal (i.e., a signal whose frequency gradually increases from small to large) or a pseudo-random encoding signal. For a one-dimensional or two-dimensional device mode, a one-point excitation multi-point receiving mode or a multi-point (all) excitation multi-point (all) receiving mode (the device is rotated after the one-dimensional linear device collects data) is adopted, and data records which uniformly cover the pile bottom are collected. The time delay dt for controlling the angle of the phased array is sin θ dx/V, θ being the phase angle. The one-dimensional array phased array acquisition mode is as follows: and (3) calculating the excitation delay time according to a time delay formula when the phase angle from left to right of the array is-Max theta, increasing the phase angle according to the angle interval d theta, receiving signals by all units, rotating the array by a certain angle phi in a certain direction after one array data is acquired, and repeating the acquisition process until the array rotation reaches 180 degrees. The two-dimensional array phased array acquisition mode is as follows: data acquisition is carried out along the X direction, the phase angle is-Max theta from left to right according to the array, the phase angle is increased according to the angle interval d theta, the excitation delay time is calculated according to a time delay formula, all units receive signals, and after the acquisition is completed, the acquisition process is repeated along the Y direction.

In the above technical solution, in the step 4), the excitation signal sequence is correlated with the acquired data to obtain a correlation coefficient sequence that changes with time, and the correlation coefficient sequence may be implemented in a time domain or a frequency domain.

In the above technical solution, in the step 5), the given length WL of the ablation window is usually a fixed value, and the length of the signal emitted by the sensor excited by the instrument can be obtained by picking up the width of the direct wave wavelet from the original received signal.

In the above technical solution, in the step 6), for each sensor transceiving array according to the observation system established in the step 3), the distances from the transmitting sensor S to the imaging point M and from the imaging point M to the receiving sensor G are calculated, and the corresponding propagation times Ts and Tg are calculated according to the speed V obtained in the step 4).

Further, the method for calculating the propagation time Ts in step 6) is as follows: for each imaging point M, calculating a distance Ri from M to each occurrence sensor Si, and then Tsi ═ Ri/V + dti, where dti is the delay time according to the i-th occurrence sensor calculated in step 3). And calculating the time Tsi from the imaging point M to the transmitting array S, and taking the minimum value as the change point Ts. The calculation of Tg is relatively simple, and only the distance Rg from the imaging point M to the receiving sensor G needs to be calculated, so that Tg is Rg/V.

Further, for the signal sequence Sig received by each sensor, the signal amplitude at the time Ts + Tg is given to the imaging point M. The above process is repeated and the signals of all transmit/receive pairs are summed cumulatively to calculate the imaging value at the imaging point M. And calculating the imaging values of all the imaging points M to obtain the three-dimensional imaging model under the observation system.

In the above technical solution, in the step 7), an initial direction α of the device is determined by using a gyroscope fixed on the device, and the three-dimensional imaging model obtained in the step 6) is rotated by an angle α, so that the final three-dimensional result is corrected to a true north (or true east) direction.

An embodiment of the present invention further provides an electronic device, where the electronic device includes: a processor and a memory for storing a computer program capable of running on the processor, the computer program when executed by the processor performing the steps of one or more of the methods described above.

An embodiment of the present invention further provides a computer-readable storage medium, where computer-executable instructions are stored in the computer-readable storage medium, and after being executed by a processor, the computer-executable instructions can implement the method according to one or more of the foregoing technical solutions.

The computer storage media provided by the present embodiments may be non-transitory storage media.

In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. The above-described device embodiments are merely illustrative, for example, the division of the unit is only a logical functional division, and there may be other division ways in actual implementation, such as: multiple units or components may be combined, or may be integrated into another system, or some features may be omitted, or not implemented. In addition, the coupling, direct coupling or communication connection between the components shown or discussed may be through some interfaces, indirect coupling or communication connection between devices or units, and may be electrical, mechanical or other driving.

The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, that is, may be located in one place, or may be distributed on a plurality of network units; some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.

In addition, all the functional units in the embodiments of the present invention may be integrated into one processing module, or each unit may be separately used as one unit, or two or more units may be integrated into one unit; the integrated unit can be realized by hardware running or by hardware and software functional units.

In some cases, any two of the above technical features may be combined into a new method solution without conflict.

In some cases, any two of the above technical features may be combined into a new device solution without conflict.

Those of ordinary skill in the art will understand that: all or part of the steps for implementing the method embodiments may be implemented by hardware related to program instructions, and the program may be stored in a computer readable storage medium, and when executed, the program performs the steps including the method embodiments; and the aforementioned storage medium includes: various media capable of storing program codes, such as a removable Memory device, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk, and an optical disk.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.