Small columnar gas explosion source signal rapid test system and analysis method

Abstract

The invention discloses a small columnar gas explosion source signal rapid test system and an analysis method, and belongs to the technical field of seismic exploration. The device comprises a seismic source, the bottom end of which is provided with a blasting opening; the pressure sensor is arranged below the seismic source, the blasting opening abuts against the pressure sensor, and the pressure sensor is used for receiving huge impact force information generated by the blasting opening and obtaining a pressure curve of the whole explosion process; and the display instrument is arranged on one side of the pressure sensor at intervals, is in line connection with the pressure sensor and is used for receiving the pressure information acquired by the pressure sensor. The system is convenient to carry, is simple and convenient to operate, is high in environmental adaptability, does not need to carry out field work, and is low in construction cost. The method for rapidly testing and analyzing the small and medium-sized columnar gas explosion source signals is simple, accurate, free of complex calculation and easy to operate, and the exploration efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of seismic exploration, and in particular to a small-scale columnar gas explosion source signal rapid testing system and analysis method. Background Art

[0002] Using artificial seismic sources to stimulate seismic waves is one of the key ways to achieve regional underground structure detection. Small cylindrical gas explosion sources, with their directional and portable characteristics, solve the problems of insufficient resolution, interference, and difficult deployment of traditional sources in shallow exploration. They are especially suitable for scenes with high requirements for accuracy and efficiency, such as engineering inspection and environmental investigation. Before this, testing and analyzing the source signal and obtaining the source energy, time-frequency characteristics and other physical properties were the prerequisites for exploration and the key to later data processing. At present, the attribute analysis method of gas explosion sources is mainly an indirect test method, that is, by deploying a certain number of detectors near the source, measuring the seismic signal generated by the source explosion, and indirectly obtaining the explosion energy and time-frequency information of the source by analyzing the measured signal. This method requires on-site construction, which is relatively cumbersome. In addition, since it is difficult to determine the parameters such as the density and velocity of the medium around the source, the explosion energy and time-frequency information obtained have different degrees of error.

[0003] Therefore, it is necessary to provide a rapid testing system and analysis method for small cylindrical gas explosion source signals. Summary of the invention

[0004] The purpose of the present invention is to provide a small columnar gas explosion source signal rapid testing system and analysis method to solve the problem that the existing technology requires on-site construction, which is relatively cumbersome, and because the parameters such as the density and velocity of the medium around the source are difficult to determine, the acquired explosion energy and time-frequency information have different degrees of errors.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A small columnar gas explosion source signal rapid testing system, comprising:

[0007] A seismic source, wherein a blasting hole is arranged at the bottom end of the seismic source;

[0008] A pressure sensor is arranged below the earthquake source, the blasting hole is in contact with the pressure sensor, and is used to receive the huge impact force information generated by the blasting hole and obtain the pressure curve of the entire explosion process;

[0009] The display instrument is arranged at a distance on one side of the pressure sensor and is connected to the pressure sensor line to receive the pressure information obtained by the pressure sensor.

[0010] Furthermore, it also includes: an isolation box for isolating the seismic source and the pressure sensor.

[0011] A method for rapid testing and analyzing small columnar gas explosion source signals is based on the small columnar gas explosion source signal rapid testing system as described above, and includes: explosion energy calculation and time-frequency characteristic analysis.

[0012] Furthermore, the steps of calculating the explosion energy are specifically as follows:

[0013] According to the initial pressure F 0 and the peak pressure F measured at the moment of explosion max , calculate the maximum net pressure F generated by the earthquake source explosion b for:

[0014] F b =F max -F 0 (1)

[0015] According to the contact area between the pressure sensor and the earthquake source as the cross-sectional area S of the cylinder, the maximum pressure P generated by the earthquake source explosion process is further calculated. max :

[0016] P max =F b ·S (2)

[0017] Substituting the source energy into the formula of available compressed gas explosion energy, the explosion energy of the source can be obtained, namely:

[0018]

[0019] Where E is the explosion energy; V is the internal volume of the container; P 1 is the internal pressure of the container; P 0 is the external pressure of the container; K is the gas adiabatic index, which represents the ratio of the specific heat at constant pressure to the specific heat at constant volume. The values ​​of carbon dioxide are 1.295; P 1 =P max .

[0020] Furthermore, the process of the time-frequency feature analysis is specifically as follows:

[0021] The frequency component can be obtained by Fourier transforming the pressure curve, and the main frequency band contained in the source signal can be extracted. At the same time, the time-frequency characteristics of the explosion process signal can be obtained by continuous wavelet transforming the pressure curve as shown in the following formula:

[0022]

[0023] In the formula, ψ α,τ is the wavelet function, τ is the translation factor, α is the scale factor, and CWT is the wavelet coefficient obtained after continuous wavelet transform, corresponding to the frequency.

[0024] The present invention has the following beneficial effects:

[0025] The rapid testing system for small and medium-sized columnar gas explosion source signals of the present invention is easy to carry, simple and convenient to operate, has strong environmental adaptability, does not require field work, and has low construction cost; the rapid testing and analysis method for small and medium-sized columnar gas explosion source signals of the present invention is simple and accurate, does not require complex calculations, is easy to operate, improves exploration efficiency, and solves the problem of the need for on-site construction in the prior art, which is relatively cumbersome, and because parameters such as the density and velocity of the medium around the source are difficult to determine, the acquired explosion energy and time-frequency information have errors to varying degrees. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a flow chart of a method for rapid testing and analyzing a small columnar gas explosion source signal provided in an embodiment of the present application;

[0027] Figure 2 It is a schematic diagram of a small cylindrical gas explosion source signal rapid testing system provided in an embodiment of the present application;

[0028] Figure 3 It is a schematic diagram of the time-frequency characteristic analysis of the earthquake source signal provided in an embodiment of the present application (a is the plane pressure normalization curve, b is the time-frequency spectrum of the earthquake source signal). DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0030] The present invention discloses a small-scale columnar gas explosion source signal rapid testing system and analysis method, which are used to analyze the explosion energy of the columnar gas explosion source and the time-frequency characteristics of its signal, improve the exploration efficiency, and solve the problems of the traditional gas explosion source attribute feature acquisition method being cumbersome, costly, time-consuming, and having large errors.

[0031] The present invention provides a small columnar gas explosion source signal rapid testing system, comprising:

[0032] The earthquake source has a blasting hole at its bottom.

[0033] The pressure sensor is set below the earthquake source, and the blasting hole is in contact with the pressure sensor to receive the huge impact force information generated by the blasting hole and obtain the pressure curve of the entire explosion process. The earthquake source and pressure sensor are placed in an isolation box to avoid interference from the outside world during the test.

[0034] The display instrument is arranged at one side of the pressure sensor and is connected to the pressure sensor line for receiving the pressure information obtained by the pressure sensor.

[0035] This embodiment includes plane pressure testing, pressure curve analysis and source attribute extraction, such as Figure 1 Specifically:

[0036] S1, plane pressure test

[0037] The plane pressure test is to obtain the plane pressure generated by the earthquake source explosion process using a plane pressure tester; the plane pressure tester includes a pressure sensor and a pressure display instrument, such as Figure 2 As shown in the figure, during the test, the bottom end of the columnar source (blasting hole) is in direct contact with the pressure sensor, and the display instrument is used to receive the pressure information obtained by the pressure sensor. After the source is detonated, the pressure sensor receives the huge impact force information generated by the blasting hole at the bottom of the source and obtains the pressure curve of the entire explosion process.

[0038] The contact area between the pressure sensor and the cylindrical gas explosion source is the cross-sectional area S of the cylinder; in the entire pressure curve F(t) measured by the plane pressure, including the initial pressure F 0 The peak pressure measured during the explosion is F max ; At the same time, the plane pressure test instrument is essentially based on Hooke's law of elastic mechanics. The measured pressure curve is equivalent to the vibration curve generated by the earthquake source explosion. Therefore, the pressure curve includes the vibration information generated at the moment of the explosion;

[0039] S2, pressure curve analysis

[0040] S21, explosion energy calculation

[0041] According to the initial pressure F 0 and the peak pressure F measured at the moment of explosion max , calculate the maximum net pressure F generated by the explosion of the columnar gas explosion source b for:

[0042] F b =F max -F 0 (1)

[0043] Therefore, the maximum pressure P generated by the earthquake source explosion process is further calculated max :

[0044] P max =F b ·S (2)

[0045] According to the energy calculation of columnar gas explosion source, the compressed gas explosion energy formula can be used, namely:

[0046]

[0047] Where E is the explosion energy; V is the internal volume of the container; P 1is the internal pressure of the container; P 0 is the external pressure of the container; K is the gas adiabatic index, which means the ratio of the specific heat at constant pressure to the specific heat at constant volume, and the values ​​for carbon dioxide are 1.295.

[0048] When the size of the columnar gas explosion source is determined, the internal volume V of the container is determined, and the external pressure P of the container is determined. 0 is normal pressure (generally, 1 standard atmosphere can be used). The gas adiabatic index K is related to the gas used in the actual gas explosion source, such as 1.295 for supercritical carbon dioxide source. 1 =P max Substituting into formula (3), the explosion energy of the columnar gas explosion source can be obtained.

[0049] S22, time-frequency feature analysis

[0050] Since the measured plane pressure curve is equivalent to the vibration curve generated by the earthquake source explosion, the plane pressure curve can be directly subjected to time-frequency analysis. The earthquake signal is a typical non-stationary signal. The plane pressure curve can be subjected to Fourier transform to obtain the frequency component, which can extract the main frequency band contained in the earthquake source signal. At the same time, in order to further analyze the time-frequency characteristics of the explosion process signal, the plane pressure curve is subjected to continuous wavelet transform, as shown in formula (4), and the time-frequency characteristics of the explosion process signal can be obtained.

[0051]

[0052] In the formula, ψ α,τ is the wavelet function, τ is the translation factor, α is the scale factor, CWT is the wavelet coefficient obtained after continuous wavelet transform, which corresponds to the frequency and realizes the transformation of the signal from time domain to frequency domain.

[0053] The rapid testing system for small and medium-sized columnar gas explosion source signals of the present invention is easy to carry, simple and convenient to operate, has strong environmental adaptability, does not require field work, and has low construction cost; the rapid testing and analysis method for small and medium-sized columnar gas explosion source signals of the present invention is simple and accurate, does not require complex calculations, is easy to operate, improves exploration efficiency, and solves the problem of the need for on-site construction in the prior art, which is relatively cumbersome, and because parameters such as the density and velocity of the medium around the source are difficult to determine, the acquired explosion energy and time-frequency information have errors to varying degrees.

[0054] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A small columnar gas explosion source signal rapid testing system, characterized in that: include: A seismic source, wherein a blasting hole is arranged at the bottom end of the seismic source; A pressure sensor is arranged below the earthquake source, the blasting hole is in contact with the pressure sensor, and is used to receive the huge impact force information generated by the blasting hole and obtain the pressure curve of the entire explosion process; The display instrument is arranged at a distance on one side of the pressure sensor and is connected to the pressure sensor line to receive the pressure information obtained by the pressure sensor.

2. The small columnar gas explosion source signal rapid testing system according to claim 1 is characterized in that: Also includes: An isolation box for isolating the seismic source and the pressure sensor.

3. A method for rapid testing and analyzing a small cylindrical gas explosion source signal, which is based on the small cylindrical gas explosion source signal rapid testing system according to any one of claims 1 to 2, characterized in that: include: Explosion energy calculation and time-frequency characteristics analysis.

4. The method for rapid testing and analyzing small columnar gas explosion source signals according to claim 3 is characterized in that: The steps of calculating the explosion energy are as follows: According to the initial pressure F0 and the peak pressure F measured at the moment of explosion max , calculate the maximum net pressure F generated by the earthquake source explosion b for: F b =F max -F0 (1) According to the contact area between the pressure sensor and the earthquake source as the cross-sectional area S of the cylinder, the maximum pressure P generated by the earthquake source explosion process is further calculated. max : P max =F b ·S (2) Substituting the source energy into the formula of available compressed gas explosion energy, the explosion energy of the source can be obtained, namely: Where E is the explosion energy; V is the internal volume of the container; P1 is the internal pressure of the container; P0 is the external pressure of the container; K is the gas adiabatic index, which represents the ratio of the specific heat at constant pressure to the specific heat at constant volume, and the values ​​of carbon dioxide are 1.295; P1 = P max .

5. The method for rapid testing and analyzing small columnar gas explosion source signals according to claim 3 is characterized in that: The process of time-frequency feature analysis is as follows: The frequency component can be obtained by Fourier transforming the pressure curve, and the main frequency band contained in the source signal can be extracted. At the same time, the time-frequency characteristics of the explosion process signal can be obtained by continuous wavelet transforming the pressure curve as shown in the following formula: In the formula, ψ α,τ is the wavelet function, τ is the translation factor, α is the scale factor, and CWT is the wavelet coefficient obtained after continuous wavelet transform, corresponding to the frequency.

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