Underground abnormal body detection method
A detection method and anomalous body technology, applied in geophysical surveys, seismology, surveying devices, etc., can solve the problems of interference of survey results, influence of building construction, small amount of collected data, etc., and achieve strong surface adaptability and wide frequency range. , the effect of high detection accuracy
Image
Examples
example 1
[0061] Such as image 3 Shown is a circular underground anomaly structure model, the background velocity is 3000m / s, the anomalous structure velocity is 340m / s, the diameter is 10m, the main frequency of the source is 60hz, and the effective frequency band is 5-150Hz.
[0062] (1) Determine the excitation point at the middle of the model surface, and determine the receiving point at 20cm on both sides of the excitation point;
[0063] (2) Vibration is carried out at the excitation point, and the reflection signal of the underground abnormal body structure is received at the receiving point;
[0064] (3) if Figure 4 As shown, the reflection signal of the underground anomalous body structure received by the receiving point is converted into a frequency spectrum by Fourier transform;
[0065] (4) pass Figure 4 It can be seen from the frequency spectrum of the underground anomalous structure that there is an obvious fluctuation peak point f 1 , f 2 , f 3 , f 4 , f 5 , f ...
example 2
[0069] In order to increase the complexity, a layered interface is added on the basis of the underground anomalous body structure model in Example 1, and it is observed whether the resonance frequency is still obvious in this case, and other conditions are not changed, such as Figure 5 Shown is a model of a subsurface anomaly structure with layered interfaces.
[0070] Repeat step (1)-step (3) of example one, detect the frequency spectrum of this model, see Figure 6 . It can be found that the frequency doubling phenomenon still exists. Therefore, in the presence of simple reflective interfaces, the resonant frequency can still be seen. The next size and length detection steps are the same as those in Example 1, and will not be repeated here.
example 3
[0072] In order to test that other graphic structures can also be detected normally, such as Figure 7 As shown in , a square underground anomalous structure model is set up, and the heights h are 5m and 10m respectively. The excitation and receiving conditions are the same as those in Example 1.
[0073] Also repeat steps (1)-step (3) to detect h 2 = Frequency spectrum of the 5m model, see Figure 8 . It can be seen that at the midpoint f of the frequency spectrum 1 =31Hz,f 2 =62Hz, f 3 = 91.5Hz appears similar frequency doubling phenomenon as example 1 and example 2, take the resonant frequency F n2 =31Hz, substituting into the length calculation formula to get h' 2 =5.48m.
[0074] See Figure 9 for h 3 = The frequency spectrum of the 10m model, it can be seen that at the midpoint f of the frequency spectrum 1 =16Hz, f 2 =31Hz,f 3 = 46.5Hz, f 4 = 64.5Hz appears a similar frequency doubling phenomenon as in Example 1 and Example 2, take the resonant frequency F...
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Description
Claims
Application Information
- IPC
- G01V1/30; G01V1/18
- CPC
- G01V1/307; G01V1/181; G01V2210/60; Y02A90/30
- Inventors
- 霍守东; 刘俊伟