阅读说明：本技术 一种基于线形台阵多次覆盖的微动数据采集方法 (Micro-motion data acquisition method based on multiple coverage of linear array ) 是由 陈基炜 赵东东 陈国光 张宝松 邸兵叶 朱红兵 王佳龙 于 2020-10-19 设计创作，主要内容包括：本发明公开一种基于线形台阵多次覆盖的微动数据采集方法,包括：布设线形台阵用于计算单点频散曲线,测点为台阵中心点；采用连续测量方式或加密测量方式,沿测线方向移动线形台阵排列进行微动信号测量,直到整条测线结束。布设一次线形台阵可以同时得到多个测点数据,与常规台阵采集方式相比,有效改善了野外工作效率、探测深度和精度,为城市复杂场地和电磁干扰环境下,开展高密度、长剖面、大深度岩性地层精细划分提供了一种新的台阵布设方式和微动数据高效、高精度采集技术。(The invention discloses a micro-motion data acquisition method based on multiple coverage of a linear array, which comprises the following steps: laying a linear array for calculating a single-point frequency dispersion curve, wherein a measuring point is the central point of the array; and moving the linear array arrangement along the line measuring direction to measure the micro-motion signal by adopting a continuous measuring mode or an encryption measuring mode until the whole line measuring is finished. The method has the advantages that multiple measuring point data can be obtained simultaneously by laying the linear array once, compared with the conventional array acquisition mode, the field working efficiency, the detection depth and the accuracy are effectively improved, and a novel array laying mode and a high-efficiency and high-accuracy micro-motion data acquisition technology are provided for developing the fine division of high-density, long-section and large-depth lithologic strata in urban complex fields and electromagnetic interference environments.)

1. A linear array multiple covering-based micro-motion data acquisition method is characterized by comprising the following steps: laying a linear array for calculating a single-point frequency dispersion curve, wherein a measuring point is the central point of the array; and moving the linear array arrangement along the line measuring direction to perform micro-motion signal test by adopting a continuous measuring mode and/or an encryption measuring mode until the whole line measuring is finished.

2. The linear array multiple coverage-based micromotion data acquisition method according to claim 1, characterized by comprising the following specific steps:

s1: setting a reasonable station spacing according to the basic relation between the maximum detection depth and the radius of the station array, and laying a linear station array by combining the position of a measuring line designed by a work area, wherein the measuring point is the central point of the linear station array;

s2: starting a data acquisition station to measure the micro-motion data;

s3: accurately positioning the position of each station and the position of each measuring point in a measuring period to obtain absolute coordinates of the positions for calculating the frequency dispersion curve of each subsequent single point;

s4: moving the whole linear array arrangement along the line measuring direction, and repeating the measuring steps of the step S2 and the step S3 every time the linear array arrangement is moved;

s5: selecting the number of stations for calculating a certain measuring point dispersion curve according to the information measured by each station and by combining the exploration depth and the measuring point density, and separating a group of station coordinates and measuring point coordinate information required for calculating the certain measuring point dispersion curve according to the station position coordinates and the measuring point position coordinates;

s6: and extracting a wave velocity dispersion curve from the micro-motion signal, then directly drawing a phase velocity contour map, or calculating the apparent transverse wave velocity, and then obtaining a two-dimensional apparent velocity profile through the processing steps of interpolation, smoothing and the like.

3. The linear array multiple coverage-based micromotion data acquisition method according to claim 2, characterized in that: before step S1 is executed, a small-range area in the work area is selected, consistency analysis of the acquired data is performed on the stations, and a station with good data consistency is selected for measurement.

4. The linear array multiple coverage-based micromotion data acquisition method according to claim 2, characterized in that: assuming that N micro-motion acquisition stations are arranged, the distance between the stations is d, calculating a single-point frequency dispersion curve by adopting N (N is less than N) stations, and making the position of the first station as the origin of coordinates, the position coordinates of the first arranged measuring points as d x (N-1)/2, and the number of the measuring points as N-N + 1.

5. The linear array multiple coverage-based micromotion data acquisition method according to claim 4, characterized in that: if a continuous measurement mode is adopted, the position coordinates of other measuring points behind the first measuring point arranged in the 1 st linear stage array are d x (N-1)/2+ d, d x (N-1)/2+2d in sequence, the measuring point interval is d, the number of the measuring points is N-N +1, and each measuring point can reflect the transverse wave speed structure of a medium below the measuring point; and then moving the whole linear array arrangement to obtain the 2 nd linear array arrangement, continuously connecting the first measuring point of the 2 nd linear array arrangement with the last measuring point of the 1 st linear array arrangement, repeating the steps S2 and S3, measuring again to obtain the information of the N-N +1 measuring points, and repeating the steps until the whole measuring line is measured.

6. The linear array multiple coverage-based micromotion data acquisition method according to claim 4, characterized in that: if an encryption measurement mode is adopted, the first linear array is arranged with first measuring point position coordinates of d x (N-1)/2, the subsequent measuring point position coordinates are d x (N-1)/2+2d, d x (N-1)/2+4d in sequence, the measuring points are N-N +1 in number, the linear array is moved to obtain a second arrangement, the second arrangement measuring point position coordinates are d x (N-1)/2+ d in sequence, d x (N-1)/2+3d in sequence, and the measuring point encryption is realized, in order to enable the measuring points to be connected between the arrangements continuously, the whole arrangement is moved along the measuring line direction again, and the process is repeated until the whole measuring line is finished.

7. The linear array multiple coverage-based micromotion data acquisition method according to claim 1, characterized in that: and extracting a wave velocity dispersion curve from the micro-motion signal by adopting a spatial autocorrelation method or a frequency wave number algorithm.

Technical Field

The invention belongs to the technical field of geophysical exploration, and particularly relates to a micro-motion data acquisition method based on multiple coverage of a linear array.

Background

The micro-motion is natural weak vibration existing on the earth shallow surface all the time, a seismic source mainly comes from natural phenomena such as air pressure, wind speed, sea waves and tidal changes and human activities such as vehicle running, machine running, daily life and production, the former is called long-wave micro-motion, the frequency is less than 1Hz, the latter belongs to constant micro-motion, the frequency is more than 1Hz, and the micro-motion belongs to a high-frequency signal source. The micromovement is a complex vibration composed of a bulk wave and a surface wave, and the energy of the surface wave (rayleigh wave and love wave) accounts for about more than 70% of the total energy. Due to the frequency dispersion characteristic of the surface waves, the micro-motion signals have the characteristic that the amplitude and the frequency change obviously along with time and space, but still meet the statistical stability within a certain space-time range, and can be described by a stable random process, so that a solid theoretical foundation is laid for people to use the micro-motion signals to carry out underground structure detection.

The micro motion detection Method (MSM for short) is a theory that The vertical component of a micro motion signal recorded by a seismic array is utilized to estimate The surface wave phase velocity, and a Rayleigh wave dispersion curve is inverted to obtain an S wave velocity structure of a medium below an observation array, so that The detection purpose is achieved. In recent years, with the continuous development of micro-motion detection methods and technologies, the micro-motion detection method and the micro-motion detection technology are widely applied to multiple fields of geological structure stratification and hidden fracture structure detection, geothermal investigation, coal mine goaf detection, karst exploration, urban geological investigation and the like, achieve good effects, and particularly have unique advantages in the aspect of poor geologic body detection represented by boulders under the urban strong interference condition.

At present, the commonly used micromotion observation arrays mainly comprise the following types: as shown in fig. 1, the shape of the nested triangle, cross, circle, L and diamond is shown in sequence. However, the following problems exist in urban data acquisition of the several observation arrays:

1) the data acquisition efficiency is low, and only one measuring point information can be acquired by single array acquisition in a unit acquisition period;

2) the layout difficulty of the micro-motion station is high due to the complex environment of the urban area, and a measuring field capable of laying a conventional array is difficult to find;

3) due to the limitation of the principle of the method, the detection depth is in direct proportion to the side length of the array, and the detection depth is limited due to the narrow field in the urban area.

Therefore, in the construction of complex urban environments, the conventional observation array is difficult to realize the high-efficiency, high-density and large-depth data acquisition of a long section, and the wide application of the micro-motion detection technology is severely restricted. However, with the increasing difficulty of exploration and the continuous application of the method, higher requirements are put on detection accuracy, detection efficiency and detection depth.

Disclosure of Invention

The technical problems solved by the invention are as follows: the measurement mode represented by a conventional circular array, a nested triangular array and the like is limited by field conditions in urban area, the working efficiency is low, the detection range is limited, the high-efficiency and high-density acquisition of long-section data is difficult to realize, and the high-precision data processing and imaging are not facilitated.

The technical scheme is as follows: in order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a linear array multiple covering-based micro-motion data acquisition method comprises the following steps: laying a linear array for calculating a single-point frequency dispersion curve, wherein a measuring point is the central point of the array; and moving the linear array arrangement along the line measuring direction to measure the micro-motion signal by adopting a continuous measuring mode and/or an encryption measuring mode until the whole line measuring is finished.

Preferably, the micro-motion data acquisition method based on multiple coverage of the linear array comprises the following specific steps:

s1: setting a reasonable station spacing according to the basic relation between the maximum detection depth and the radius of the station array, and laying a linear station array by combining the position of a measuring line designed by a work area, wherein the measuring point is the central point of the linear station array;

s2: starting a data acquisition station to measure the micro-motion data;

s3: accurately positioning the position of each station and the position of each measuring point in a measuring period to obtain absolute coordinates of the positions for calculating the frequency dispersion curve of each subsequent single point;

s4: moving the whole linear array arrangement along the line measuring direction, and repeating the measuring steps of the step S2 and the step S3 every time the linear array arrangement is moved;

s5: selecting the number of stations for calculating a certain measuring point dispersion curve according to the information measured by each station and by combining the exploration depth and the measuring point density, and separating a group of station coordinates and measuring point coordinate information required for calculating the certain measuring point dispersion curve according to the station position coordinates and the measuring point position coordinates;

s6: and extracting a wave velocity dispersion curve from the micro-motion signal, then directly drawing a phase velocity contour map, or calculating the apparent transverse wave velocity, and then obtaining a two-dimensional apparent velocity profile through the processing steps of interpolation, smoothing and the like.

Preferably, before step S1 is executed, a small-range area in the work area is selected, the station is analyzed for consistency of the collected data, and a station with good data consistency is selected for measurement.

Preferably, assuming that there are N micro-motion acquisition stations, the station spacing is d, calculating a single-point dispersion curve by using N (N < N) stations, and making the position of the first station as the origin of coordinates, the position coordinates of the first arranged measuring points are d x (N-1)/2, and the number of the measuring points is N-N + 1.

Preferably, if a continuous measurement mode (fig. 4) is adopted, the position coordinates of the measuring points behind the first measuring point of the 1 st linear array are d x (N-1)/2+ d, d x (N-1)/2+2d in sequence, the measuring points are at a distance d, the number of the measuring points is N-N +1, and each measuring point can reflect the transverse wave velocity structure of the medium below the measuring point; and then moving the whole linear array arrangement to obtain the 2 nd linear array arrangement, continuously connecting the first measuring point of the 2 nd linear array arrangement with the last measuring point of the 1 st linear array arrangement, repeating the steps S2 and S3, measuring to obtain the information of the N-N +1 measuring points, and repeating the steps until the whole line measuring test is finished.

Preferably, if an encryption measurement mode (fig. 6) is adopted, the first linear stage array is arranged with first measuring point position coordinates of d × (N-1)/2, the subsequent measuring point position coordinates are d × (N-1)/2+2d, d × (N-1)/2+4d in sequence, and the measuring points are N-N +1, the linear stage array is moved to obtain a second array, the second array measuring point position coordinates are d × (N-1)/2+ d, d × (N-1)/2+3d in sequence, and the measuring point encryption is realized, so that the connecting measuring points between the arrays are continuous, the whole array is moved along the measuring line direction again, and the process is repeated until the whole measuring line is finished.

Preferably, a spatial autocorrelation method or a frequency-wavenumber (F-K) algorithm is used to extract a wave velocity dispersion curve from the micromotion signal.

Has the advantages that: compared with the prior art, the invention has the following advantages:

according to the micro-motion data acquisition method based on multiple coverage of the linear array, multiple measuring point data can be obtained simultaneously by arranging the linear array once, compared with a conventional array acquisition mode, the field working efficiency, the detection depth and the detection precision are effectively improved, and a novel array arrangement mode and a micro-motion data high-efficiency and high-precision acquisition technology are provided for carrying out fine division of high-density, long-section and large-depth lithologic strata in urban complex fields and electromagnetic interference environments.

Drawings

FIG. 1 is a schematic diagram of a conventional micro-motion observation array;

FIG. 2 is a schematic diagram of a linear array of the present invention;

FIG. 3 is a single point frequency dispersion spectrum and dispersion curve of a conventional array and a linear array according to the present invention;

FIG. 4 is a schematic diagram of the layout of a linear multi-coverage continuous array according to the present invention;

FIG. 5 is a schematic diagram of the layout of an encryption array according to the present invention;

fig. 6 is a schematic diagram of the layout of the encryption array based on linear multi-coverage in the present invention.

Detailed Description

The present invention will be further illustrated by the following specific examples, which are carried out on the premise of the technical scheme of the present invention, and it should be understood that these examples are only for illustrating the present invention and are not intended to limit the scope of the present invention.

The micro-motion data acquisition method based on multiple coverage of the linear array comprises the following steps: laying a linear array for calculating a single-point frequency dispersion curve, wherein a measuring point is the central point of the array; and moving the linear array arrangement along the line measuring direction to perform micro-motion signal test by adopting a continuous measuring mode and/or an encryption measuring mode until the whole line measuring is finished. The method is mainly used for high-efficiency and high-precision exploration of geothermal structures, stratum interfaces, faults, boulders, collapse columns, goafs, karsts, roadbed and pavement non-compact areas and the like. The embodiment is described by taking a linear array continuous measurement mode along the subway shield as an example, and the specific steps are as follows:

before testing, the consistency analysis of the collected data is firstly carried out on the stations, and the stations with good data consistency are selected for measurement. Selecting a small-range area with uniform underground medium and flat surface, connecting each station with a respective micro detector, closely and adjacently arranging and measuring for 40 minutes, extracting stable micro signals from the micro detectors for analysis, judging whether the data collected by each station have consistency, if so, carrying out next formal measurement, and if not, removing the instrument for formal measurement.

S1: setting a reasonable station spacing d according to the basic relation between the maximum detection depth and the radius of the linear station, and laying the linear station by combining the position of a measuring line designed by a work area, wherein the measuring point is the central point of the linear station; and assuming that the coordinates of the first station are the origin of coordinates, the distance between the stations is d, and the number of the stations is n, the measured point is the central point of the linear array, namely the coordinates are d x (n-1)/2. Here, for example, 12 acquisition stations calculate a measurement point dispersion curve, and the measurement point is a central point of the array, namely 5.5 × d.

S2: starting a data acquisition station to perform micro-motion data measurement:

checking a GPS antenna, a battery and a data acquisition indicator lamp on the micro-motion acquisition station to ensure that the indicator lamp displays no abnormity, withdrawing instrument operators after the data acquisition station works normally, and filling a micro-motion measurement field record table, wherein the measurement time is 35-45 minutes;

s3: in a measurement period, accurately positioning the position of each station and the position of a measuring point by using RTK (Real-Time Kinematic), and obtaining an absolute coordinate of the RTK for calculating a subsequent single-point dispersion curve;

s4: moving the whole linear array arrangement along the line measuring direction, and repeating the measuring steps of the step S2 and the step S3 every time the linear array arrangement is moved; the step can adopt two measuring modes, namely a linear array continuous measuring mode and a linear array encryption measuring mode.

A linear array continuous measurement mode is used for reference of the thought of a seismic exploration multi-coverage observation system, N micro-motion acquisition stations are assumed, the station spacing is d, N (N is less than N) stations are adopted to calculate a single-point frequency dispersion curve, the position of a first station is made to be the origin of coordinates, the position coordinates of a first measuring point arranged on the first linear array are d x (N-1)/2, the position coordinates of subsequent measuring points are d x (N-1)/2+ d, d x (N-1)/2+2d in sequence, and the. Taking 24 acquisition stations as an example (fig. 4), laying a first linear array arrangement, measuring time is 35-45 minutes, the number of the measuring points is N-N +1, moving the whole arrangement along the measuring line direction in sequence in order to ensure that the measuring points are continuously connected between the arrangements, and circulating the sequence until the whole measuring line is finished, thereby effectively improving the micro-motion field acquisition efficiency and exploration precision (table 1). The efficiency and accuracy verification test is as follows:

taking a working system of 8 hours every day and 24 micro-motion acquisition stations as an example, assuming that the observation time is 45 minutes, the moving array or the arrangement time is 15 minutes, one group of circular array, triangular array, rhombic array and cross array needs 12 acquisition stations, the measurement is carried out in two groups, and the linear arrangement needs 24 acquisition stations. As can be seen from table 1: compared with a conventional array observation mode, the linear array-based micro-motion data acquisition technology for multiple coverage of the similar earthquake can greatly improve the field work efficiency, indirectly increase the density of the measuring points, and further effectively improve the detection precision.

Based on the comparison of the single-point dispersion curves (fig. 3), the transverse wave apparent velocity profiles of the circular array and the linear array are further compared (as shown in fig. 5). As can be seen from the figure: the linear distribution profile is less noisy overall than the circular distribution profile, the transverse layering is more in accordance with geological rules, and the longitudinal resolution is more detailed than the circular distribution profile; the 18 m shallow layering rules are the same, the layout range is limited, the detection depth of circular layout is limited, the deep speed continuity of the section is poor, and the deep speed section continuity of the linear array is good; the circular array has low working efficiency, is difficult to realize long-section and high-density continuous measurement, and the linear array has high working efficiency, thereby being very beneficial to long-section, high-efficiency and high-density data acquisition (table 1).

A linear stage array encryption measurement mode is based on the thought of a seismic exploration multi-coverage observation system, N micro-motion acquisition stations are assumed, the station spacing is d, N (N is less than N) stations are adopted to calculate a single-point frequency dispersion curve, the position of a first station is made to be the origin of coordinates, the position coordinates of a first measurement point arranged at the first stage are d x (N-1)/2, the position coordinates of subsequent measurement points are d x (N-1)/2+2d in sequence, d x (N-1)/2+4d in sequence, the. Taking 24 acquisition stations as an example (fig. 6), laying a first linear array arrangement, measuring time is 35-45 minutes, the number of measuring points is N-N +1, sequentially moving the linear array to obtain a second arrangement, realizing measuring point encryption, moving the whole arrangement along the measuring line direction again in order to ensure that the measuring points are continuously connected between the arrangements, and circulating the whole arrangement until the whole measuring line is finished, thereby improving the field micro-motion acquisition efficiency and exploration precision (table 1).

Table 1 statistics table for field data collection efficiency of different arrays (24 collection stations)

S5: selecting the number of stations for calculating a certain measuring point dispersion curve according to the information measured by each station and by combining the exploration depth and the measuring point density, and separating a group of station coordinates and measuring point coordinate information required for calculating the certain measuring point dispersion curve according to the station position coordinates and the measuring point position coordinates;

s6: and extracting a wave velocity dispersion curve from the micro-motion signal by adopting a space autocorrelation method or a frequency wave number (F-K) algorithm, then directly drawing a phase velocity contour map, or calculating the apparent transverse wave velocity, and then carrying out processing steps such as interpolation, smoothing and the like to obtain a two-dimensional apparent velocity profile. The phase velocity contour map or the apparent transverse wave velocity profile can intuitively reflect the change of the lithology of the stratum and is the basic basis of geological interpretation.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.