CN-121348462-B - Multi-physical-field online detection and evaluation method for railway roadbed and underlying stratum in frozen soil area

CN121348462BCN 121348462 BCN121348462 BCN 121348462BCN-121348462-B

Abstract

The invention discloses a multi-physical field online detection and evaluation method for railway roadbeds and subsurface strata in frozen soil areas, which is used for rapidly processing the observed data of a direct current electric field and a seismic wave field by periodically exciting and observing the direct current electric field and the seismic wave field and uploading the data in a networking way, realizing the real-time detection of the compactness of the structure of the railway roadbeds and the upper and lower limits of the subsurface frozen soil layers, and rapidly and accurately grasping the change conditions of the structure of roadbed bodies and the subsurface frozen soil layers at short intervals without damage, providing safety early warning for railway infrastructure and providing early warning reference standards. The observation system has the advantages of low manufacturing cost, convenient installation, long-life installation benefit, large detection depth and real-time detection by the detection method, less humanization, intelligent detection and the like, can meet the operation detection requirements of engineering operations such as plateau railways, highways and the like, and provides a safety early warning method and equipment for roadbed engineering such as railways, highways and the like.

Inventors

ZHAO GUANGMAO
JIANG CHUANG
FENG YANQIAN
LIU ZHE
QI XIAOYU
SONG XIANGYU
YAO YU
ZHANG HAIYANG
NIU YONGXIAO
WANG QIANLONG
LI MINGJUN
LI GUOHE
Shang Chaojie
QI CHUNYU
WANG RAN
WANG GUANCHAO
LIN YONGWEI
SUN JUN
HAN JIAN
XIE ZHIWEN

Assignees

中国铁路设计集团有限公司

Dates

Publication Date: 20260512
Application Date: 20251217

Claims (8)

1. The method for online detection and evaluation of the multiple physical fields of the railway roadbed and the underlying stratum in the frozen soil area is characterized by comprising the following steps of: S1, arranging electric shock distributed detection devices along the road shoulders at two sides of a roadbed, wherein the electric shock distributed detection devices comprise resistivity seismic wave integrated detectors and shock and electricity integrated sensors; S2, periodically applying a direct current electric field and a seismic wave field, periodically receiving direct current electric field data and seismic wave field data, and preprocessing; s3, performing direct current-seismic wave double-field joint inversion on the preprocessed direct current electric field data and the seismic wave field data to obtain a conductivity model and a Rayleigh wave velocity model of the underground space; Performing direct current-seismic wave double-field joint inversion on the preprocessed direct current electric field data and the seismic wave field data, wherein the direct current-seismic wave double-field joint inversion comprises the following steps: s301, constructing a joint inversion objective function Wherein: And Fitting terms of the direct current electric field and the seismic wave field observation data are respectively adopted, Wherein Is a cross gradient term; The direct current electric field conductivity of the model; the Rayleigh wave velocity of the seismic waves; S302, initializing each grid point of the underground space according to an empirical value, and assigning an initial conductivity and an initial Rayleigh wave speed to each grid point; S303, inputting the obtained initial conductivity and initial Rayleigh wave speed into a conductivity model and a wave speed model respectively, and forward modeling by using the conductivity model to obtain a theoretical electric field response value; S304, inputting the calculated theoretical electric field, the wave velocity response value, the preprocessed direct current electric field data and the preprocessed seismic wave field data into a constructed joint inversion objective function, and calculating residual errors; S305, judging whether the residual error meets the precision requirement, and outputting the conductivity model and the wave velocity model at the moment if the residual error meets the precision requirement; If the model parameters do not meet the requirements, the derivative of each model parameter in the joint inversion objective function is formed into a jacobian matrix; s306, solving direct current electric field conductivity by adopting Jacobian matrix And the Rayleigh wave velocity of the seismic wave Obtain the updated quantity of the conductivity of the direct current electric field by the cross gradient function of (2) And the speed update amount of the Rayleigh wave of the seismic wave ; S307, after updating the conductivity and the Rayleigh wave speed according to the updating quantity, inputting the updated conductivity and the Rayleigh wave speed into a conductivity model and a wave speed model, and repeating the steps S304-S306 to calculate the residual error again until the residual error converges; S4, generating resistivity profiles of roadbed and underlying stratum based on the conductivity model, and generating Rayleigh wave velocity profiles based on the Rayleigh wave velocity model; s5, calculating the compactness of the roadbed based on the Rayleigh wave velocity profile, and calculating the upper limit and the lower limit of the frozen soil layer based on the resistivity profile; s6, performing time shift analysis on the upper limit and the lower limit of the roadbed compactness and the frozen soil layer, wherein the time shift analysis comprises the following steps: analyzing the shear wave velocity change rate; the shear wave velocity profile at the time t 1 is differenced with the shear wave velocity profile at the time t 2 , so that a shear wave velocity change section in the delta t period is obtained; Dividing the section according to preset grids, and calculating the shear wave speed change rate in each grid; drawing sectional views based on the shear wave speed change and the change rate respectively; The resistivity change rate analysis includes: by means of Time resistivity And (3) with The resistivity at the moment is subjected to difference to obtain Section of change in resistivity during time Calculating the total resistivity change rate of the Deltat time period , The section was subdivided into 0.1m x 0.1m grids with resistivity of each region According to the formula Obtaining the change rate of resistivity , The water content in the roadbed is reduced, the structure is strengthened, Indicating the increase of water content and the weakening of strength in the roadbed, and changing with resistivity And rate of change Drawing sectional views for attributes respectively; Upper and lower limit heights of frozen soil layer and (3) program change analysis: The upper limit elevation and the lower limit elevation of the frozen soil layer at the time t 1 are respectively different from the upper limit elevation and the lower limit elevation Gao Chengzuo of the frozen soil layer at the time t 2 , so that the upper limit elevation and the lower limit elevation variation of the frozen soil layer in the delta t period are obtained; and S7, carrying out safety precaution and status report on the railway subgrade based on the time shift analysis result.
2. The method for on-line detection and evaluation of multiple physical fields of a railway subgrade and an underlying stratum in a frozen earth area according to claim 1, characterized in that in S2, the pretreatment comprises the following steps: calculating apparent resistivity by using the retained DC electric field data; band-pass filtering and wave body cutting are carried out on the seismic wave field data, and noise data are filtered; performing two-dimensional Fourier transform on the reserved seismic wave field data to obtain a power spectrum, and extracting a dispersion curve by using the power spectrum.
3. The method for online detection and evaluation of multiple physical fields of a railway subgrade and an underlying stratum in a frozen earth area according to claim 1 is characterized in that in the step S4, a resistivity profile and a Rayleigh wave velocity profile of the subgrade and the underlying stratum are generated, a conductivity model obtained after joint inversion is converted into a resistivity model, the resistivity value of each grid is represented by different colors or contours by taking a horizontal distance as an abscissa and taking a depth as an ordinate to form a resistivity profile, the Rayleigh wave velocity model outputted by inversion is utilized, and the wave velocity value of each grid is represented by different colors or contours by taking the horizontal distance as the abscissa and taking the depth as an ordinate to form the Rayleigh wave velocity profile.
4. The method for online detection and evaluation of multiple physical fields of a railway subgrade and an underlying stratum in a frozen earth area according to claim 1, wherein in S5, when the compactness of the subgrade is calculated, the Rayleigh wave velocity in the Rayleigh wave velocity profile is calculated according to the Rayleigh wave velocity Calculating the speed of shear wave in roadbed structure , Wherein v is poisson ratio, and the soil roadbed v is 0.25 , The unit is m/s.
5. The method for online detection and evaluation of multiple physical fields of railway roadbed and underlying stratum in frozen earth area according to claim 4, wherein the internal shear wave velocity of the roadbed structure is classified according to the following classification level: When Vs < 150 m/s, the roadbed structure area is divided into loose and low bearing capacity areas; dividing a roadbed structure area with Vs=150-300 m/s into a medium compact area; when Vs > 300 m/s roadbed structure area is divided into high-compactness areas.
6. The method for online detection and evaluation of multiple physical fields of a railway subgrade and an underlying stratum in a frozen earth area according to claim 4, characterized in that in S5, determining upper and lower limits of a frozen earth layer based on the resistivity profile comprises: Drawing a resistivity-depth curve from the surface down on the resistivity profile; identifying a first inflection point on the resistivity-depth curve, wherein the resistivity value of the first inflection point is rapidly increased, and determining the depth corresponding to the first inflection point as the upper limit of frozen soil; continuing downwards from the upper limit of the frozen soil, identifying a second inflection point of the rapid decrease of the resistivity value on the resistivity-depth curve, and determining the depth corresponding to the second inflection point as the lower limit of the frozen soil layer; Repeating the above process at a plurality of measuring points along the roadbed, connecting the upper limit of the frozen soil of all the measuring points to form an upper limit line of the frozen soil, and connecting the lower limit of the frozen soil layer of all the measuring points to form a lower limit line of the frozen soil.
7. A multi-physical-field online detection and evaluation system for a railway roadbed and an underlying stratum in a frozen soil area is characterized by comprising the following components: The resistivity seismic wave integrated detectors are distributed on road shoulders at two sides of the roadbed and are used for periodically exciting and receiving a direct current electric field and a seismic wave field; the system comprises two detectors, two cables, a plurality of seismoelectric integrated sensors, a plurality of electromagnetic sensors and a plurality of electromagnetic sensors, wherein the two cables are connected with each detector, and are arranged along the line direction; the data processing and early warning server is used for receiving the collected direct current electric field data and the seismic wave field data and executing the method according to any one of claims 1-6 to generate early warning information.
8. The frozen soil area railway subgrade and underlying stratum multi-physical field online detection and evaluation system according to claim 7, wherein the data processing and early warning server is integrated with algorithms for performing direct current-seismic wave double-field joint inversion, subgrade compactness calculation, frozen soil layer upper and lower limit determination and time shift analysis.

Description

Multi-physical-field online detection and evaluation method for railway roadbed and underlying stratum in frozen soil area Technical Field The invention relates to the technical field of railway engineering exploration, in particular to a multi-physical-field online detection and evaluation method for a railway subgrade and an underlying stratum in a frozen soil area. Background The measurement of the underlying stratum of the railway subgrade can be divided into two stages of construction period investigation and operation period monitoring, when the operation period is monitored for a long time, the railway engineering usually utilizes an electromagnetic method to conduct stratum investigation, but at present, the survey work is mainly conducted in a mode of uniformly distributing measuring points, especially the area survey work is conducted, the time is long, the investigation aging is difficult to ensure, the requirements of the engineering such as a plateau railway on rapid and high-frequency detection are difficult to meet, the follow-up engineering investigation design work is influenced, meanwhile, the point distribution survey is conducted on a large area, and the cost waste is high. The conventional method is mostly 'disposable' or 'staged' detection, continuous and time-shift (time-lapse) monitoring cannot be realized, and dynamic changes of frozen soil and roadbed states are difficult to capture in time. Therefore, new investigation modes and algorithms are required to be researched to improve the investigation efficiency and save the exploration expenses. Disclosure of Invention Therefore, the invention aims to provide the method and the system for online detection and evaluation of the railway subgrade and the underlying stratum in multiple physical fields in the frozen soil region, solve the problem that the railway subgrade is difficult to monitor the health condition of the internal structure in real time, nondestructively and comprehensively in the operation period in the complex geological regions such as frozen soil and realize intelligent safety early warning. In order to achieve the above purpose, the method for online detection and evaluation of multiple physical fields of the railway roadbed and the underlying stratum in the frozen soil area provided by the invention comprises the following steps: S1, arranging electric shock distributed detection devices along the road shoulders at two sides of a roadbed, wherein the electric shock distributed detection devices comprise resistivity seismic wave integrated detectors and shock and electricity integrated sensors; S2, periodically applying a direct current electric field and a seismic wave field, periodically receiving direct current electric field data and seismic wave field data, and preprocessing; s3, performing direct current-seismic wave double-field joint inversion on the preprocessed direct current electric field data and the seismic wave field data to obtain a conductivity model and a Rayleigh wave velocity model of the underground space; S4, generating resistivity profiles of roadbed and underlying stratum based on the conductivity model, and generating Rayleigh wave velocity profiles based on the Rayleigh wave velocity model; s5, calculating the compactness of the roadbed based on the Rayleigh wave velocity profile, and calculating the upper limit and the lower limit of the frozen soil layer based on the resistivity profile; S6, performing time shift analysis on the compactness of the roadbed and the upper limit and the lower limit of the frozen soil layer; and S7, carrying out safety precaution and status report on the railway subgrade based on the time shift analysis result. Further preferably, in S2, the preprocessing includes the steps of: calculating apparent resistivity by using the retained DC electric field data; band-pass filtering and wave body cutting are carried out on the seismic wave field data, and noise data are filtered; performing two-dimensional Fourier transform on the reserved seismic wave field data to obtain a power spectrum, and extracting a dispersion curve by using the power spectrum. Further preferably, in S3, performing direct current-seismic wave dual-field joint inversion on the preprocessed direct current electric field data and the seismic wave field data, including: S301, constructing a joint inversion objective function; Wherein: And Fitting terms of the direct current electric field and the seismic wave field observation data are respectively adopted,Wherein、Is a cross gradient term; The direct current electric field conductivity of the model; the Rayleigh wave velocity of the seismic waves; S302, initializing each grid point of the underground space according to an empirical value, and assigning an initial conductivity and an initial Rayleigh wave speed to each grid point; S303, inputting the obtained initial conductivity and initial Rayleigh wave speed into a conductivity model and a wav