A high-accuracy and efficient acquisition method of vehicle seismic source signals on a high-flatness road

Abstract

The application discloses a kind of high flatness road's vehicle seismic source signal accurate efficient collection method, it is related to vehicle seismic source signal collection technical field, including the following steps: S1: along the road and lay detector;S2: along the road and lay detector vertically.This application method starts from engineering practice, by changing the collection mode, increase vertical detector on the basis of traditional along the road and lay detector, form L-shaped layout mode in the road plane.Effectively solve the influence problem of surrounding environmental noise on dispersion curve, and collection is convenient and efficient, without considering the wave field propagation direction corresponding to different frequencies, less detector is needed, the requirement to collection space is very low, suitable for urban high flatness road, has strong application potential in the present stage of road vehicle signal collection and processing.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle seismic source signal collection, in particular to a vehicle seismic source signal accurate and efficient collection method for high flatness road. BACKGROUND

[0002] With the increasing demand for sustainable development and expansion of cities, more and more subways for transporting commuters, buildings for accommodating public facilities and services, and storage of materials and special goods are planned in underground space, making the development and protection of underground space more and more important. Before the excavation of underground space, exploration is needed to find out possible abnormal geological bodies and geological structures such as groundwater. During the excavation process and after the completion, there may be disturbance of the overlying bottom layer, which needs to be continuously monitored. Due to the complexity of the near-surface space medium, an accurate and convenient near-surface investigation method is the key to the construction of underground space.

[0003] At present, the collection and processing of vehicle seismic source signals mainly includes two methods. One is to arrange geophones along the road or railway line and use seismic interference method to extract dispersion curves. The other is to use a multi-directional linear collection array to calculate the wave field propagation direction and determine the collection array consistent with the wave field propagation direction to extract dispersion curves. The first method does not consider the strong environmental noise from factories, buildings and other sources in the city, which causes errors in the extracted dispersion curve phase velocity. The second method requires a high collection space and needs to calculate the wave field propagation direction, which is low in efficiency. Zhang Yuguang et al. designed a multi-directional linear collection array and calculated the energy azimuth distribution of the collected signals, selected a row of geophone signals consistent with the strong energy propagation direction, and used seismic interference method to extract dispersion curves, obtaining relatively accurate dispersion curves. In the case of high road flatness, the energy of vehicle seismic source is low, and the azimuth angle of surrounding strong sources cannot be ignored. The scheme proposed by Zhang Yuguang et al. has a large requirement for collection space and needs to calculate the wave field propagation direction in advance.

[0004] Therefore, it is urgent to study a vehicle seismic source signal accurate and efficient collection method for high flatness road. SUMMARY

[0005] To solve the above technical problems, the present application discloses a vehicle seismic source signal accurate and efficient collection method for high flatness road. The present application increases vertical geophones on the basis of traditional road geophone arrangement, which can effectively reduce the influence of surrounding environmental noise and realize accurate extraction of dispersion curves. At the same time, due to the small number of added geophones, the present application is not restricted by space range in urban space.

[0006] To achieve the above purpose, the present application adopts the following technical scheme:

[0007] A kind of high flatness road vehicle seismic source signal accurate and efficient acquisition method, comprising the following steps:

[0008] S1: along the road, detector is laid out;

[0009] S2: along the road, detector is laid out vertically.

[0010] Optionally, in step S2, the number of vertically laid detectors is 2-5.

[0011] The beneficial effects of the present application are,

[0012] The method of the present application starts from engineering practice, by changing the acquisition mode, increasing the vertical detector on the basis of traditional along the road detector, forming L-shaped layout in the road plane, effectively solving the problem of the influence of surrounding environmental noise on dispersion curve, and the acquisition is convenient and efficient, without considering the wave field propagation direction corresponding to different frequencies, the required detector is less, the requirement to acquisition space is very low, suitable for urban high flatness road, has strong application potential in present road vehicle signal acquisition and processing. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 It is a high flatness road vehicle seismic source signal accurate and efficient acquisition method flowchart of the present application;

[0014] Figure 2 It is the data acquisition diagram of the high flatness road vehicle seismic source signal accurate and efficient acquisition method of the present application, wherein (a) and (b) are detection area and observation system distribution, (c) is the acquisition signal of part of south-north array;

[0015] Figure 3 It is the dispersion curve extraction process and result comparison diagram of two directions of L-shaped array and L-shaped array as a whole in the present application;

[0016] Figure 4 It is the dispersion curve extraction result inversion result and drilling data in the present application, wherein (a) is the inversion result of different dispersion curves, (b) is the comparison result of inversion obtained dispersion curve and real dispersion curve, (c), (d), (e) are drilling data, (f) is the angle distribution diagram of the connecting line path between any two detectors;

[0017] Figure 5 It is the angle distribution diagram of the connecting line path between any two detectors when vertically laying detector in the present application, wherein (a) is vertically laying five detectors, (c) is vertically laying three detectors, (b) and (d) are corresponding dispersion extraction results. DETAILED DESCRIPTION

[0018] 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 embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] Example 1

[0020] A precise and efficient method for acquiring vehicle seismic source signals from highly smooth roads, such as... Figure 1 As shown, it includes the following steps:

[0021] S1: Install detectors along the road;

[0022] S2: Install detectors vertically along the road.

[0023] Optionally, in step S2, the number of detectors arranged vertically is 2 to 5.

[0024] Example 2

[0025] In this alternative embodiment, such as Figure 2 As shown, there is a large number of vehicles on the national highway to the east, and few buildings around it. There is a village located about 30° south of west of the detector array. 31 detectors are deployed in the north-south direction and 31 detectors are deployed in the east-west direction. The channel spacing is 2 meters, the sampling interval is 1ms, and the sampling time is 4 hours.

[0026] like Figure 3 As shown, dispersion curves were extracted from the two directions of the L-shaped array and the entire L-shaped array, resulting in three dispersion curves. The three dispersion curves basically overlap in the region above 10Hz, while in the low-frequency region, there are significant differences in phase velocity. The phase velocity in the north-south direction is significantly greater than that in the east-west direction, and the phase velocity of the overall extracted dispersion curve is the smallest. The reason for this is that the low-frequency signal is greatly affected by villages. Therefore, the detector array deployed along the road cannot obtain accurate dispersion curves, and detectors need to be deployed in other directions for correction.

[0027] The shear wave velocity was inverted from the dispersion curve extraction results described above, and the inversion results were compared with the borehole results in this area. Figure 4As shown, the borehole data shows consistent results with the dispersion inversion results of the L-shaped array as a whole, and large differences with the dispersion inversion results of the two single directions, indicating that the use of multi-directional acquisition array and dispersion extraction can effectively correct the influence of wave field propagation direction, and obtain effective underground dispersion information; Because in the dispersion curve extraction process, cross-correlation operation is required between any two geophones, the direction of two geophones in the traditional linear geophone arrangement is fixed, while the arrangement method proposed in this method can cover multiple angles between two geophones, such as Figure 4 (f) shown, the source angle is corrected, so that the dispersion curve is more accurate, and because the wave field direction is different for different frequencies, this method can eliminate the influence of different frequencies on the wave field propagation direction.

[0028] Due to space limitations, too many geophones cannot be arranged in the vertical direction in the city, so more efficient acquisition methods are needed, such as Figure 5 As shown, Figure 5 (a) and (c) in the middle are angle distribution diagrams of the connecting line paths between any two geophones when 5 geophones and 3 geophones are arranged vertically, Figure 5 (b) and (d) in the middle are the corresponding dispersion extraction results, which shows that on the basis of the previous road geophone array, 3-5 geophones can be arranged vertically to correct the dispersion curve.

[0029] Of course, the above description is not a limitation of the present application, and the present application is not limited to the above examples, and changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present application should also be within the scope of the present application.

Claims

1. A high-accuracy and efficient acquisition method of vehicle seismic source signals of a high-flatness road, characterized in that, The method comprises the following steps: S1: arranging detectors along a road; S2: arranging detectors vertically along the road; The process of arranging detectors along the road and arranging detectors vertically along the road is specifically as follows: The number of detectors arranged vertically along the road is 2-5 rows, the row spacing is 2 meters, the sampling interval is 1 ms, and the sampling duration is 1 hour; The method for extracting the dispersion characteristics by using the detectors arranged along the road and the detectors arranged vertically along the road is specifically as follows: An L-shaped multi-directional acquisition array is adopted, a plurality of groups of observation pairs are constructed by using the two-by-two combination of detectors, and the multi-angle coverage of the wave field propagation direction is realized by using the angle distribution of the connecting line path between any two detectors; The cross-correlation operation is performed on the seismic data recorded by any two detectors to extract the dispersion characteristics and obtain the dispersion curve; The process of realizing the multi-angle coverage of the wave field propagation direction is specifically as follows: The angle distribution of the connecting line path between any two detectors is calculated by using the detector arrangement parameters.

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