CN-122016199-A - Municipal concrete drainage pipeline leakage detection and positioning method

CN122016199ACN 122016199 ACN122016199 ACN 122016199ACN-122016199-A

Abstract

The invention discloses a municipal concrete drainage pipeline leakage detection and positioning method. Arranging a plurality of parallel measuring lines above a pipeline to be detected to form a detection grid, collecting radar full-waveform data, introducing the spatial attribute of a known pipeline as constraint, obtaining three-dimensional spatial distribution of dielectric constant and conductivity of soil around the pipeline through full-waveform inversion, substituting the parameters into a soil dielectric constant model and a conductivity model respectively, jointly inverting the three-dimensional distribution of water content and porosity of the soil, judging the spatial position of a leakage point or section through analyzing the three-dimensional morphological characteristics of an abnormal region of the water content and the porosity, further calculating the leakage severity index to quantitatively evaluate the leakage grade, and combining the pipeline endoscopic detection result to verify.

Inventors

LEI JIANWEI
FANG HONGYUAN
HU ZIHAO
Wan Jingru
WANG NIANNIAN
Xue Binghan
LI BIN

Assignees

郑州大学
黄河实验室(河南)

Dates

Publication Date: 20260512
Application Date: 20260209

Claims (10)

1. A municipal concrete drainage pipeline leakage detection and positioning method is characterized in that dielectric constant and conductivity distribution of soil around a pipeline are obtained through full waveform inversion based on ground penetrating radar full waveform data acquired in a non-contact mode above the pipeline, then water content and porosity distribution of the soil are obtained through joint inversion, and leakage conditions and influence ranges are judged according to the water content and the porosity distribution.
2. The municipal concrete drainage pipeline leakage detection and positioning method according to claim 1, comprising the following steps: Step 1, arranging a ground penetrating radar measuring line above a drainage pipeline to be detected, and collecting radar full-waveform data containing arrival time, amplitude and phase information; Step 2, based on the radar full waveform data, acquiring dielectric constant and conductivity spatial distribution of soil around the pipeline by a full waveform inversion method; Step 3, introducing the dielectric constant and the conductivity into a soil body dielectric constant model and a conductivity model respectively, and inverting the water content and the porosity distribution of soil bodies around the pipeline; step 4, judging whether the pipeline has pipeline leakage and the extravasation area according to the abnormal characteristics of the water content and the porosity in the inversion result: The normal disease-free state is that the water content, the porosity and the conductivity of the soil around the pipeline are close to the background value, the spatial distribution is uniform, and no obvious abnormality exists; The sewage leakage state is that the water content and the porosity of soil around the pipeline are obviously higher than the background value to form a continuous abnormal region, the continuous abnormal region corresponds to the position of the drainage pipeline in space, the pipeline leakage is judged to exist at the position, and the leakage area is identified through the size of the abnormal region.
3. The municipal concrete drainage pipeline leakage detection and positioning method according to claim 2 is characterized in that in the step 1, the arrangement of the ground penetrating radar measuring lines is specifically that a plurality of mutually parallel ground penetrating radar measuring lines are arranged along the trend of the drainage pipeline to be detected to form a detection grid covering the pipeline and soil bodies on two sides of the pipeline, and in the step 2, three-dimensional space distribution of dielectric constants and conductivities of the soil bodies around the pipeline is obtained.
4. The method for detecting and positioning leakage of a municipal concrete drainage pipeline according to claim 3, wherein in the step 1, the distance between a plurality of parallel measuring lines is determined according to the pipe diameter and the burial depth of the drainage pipeline, and the distance is in a range of 0.5 to 1.5 times of the pipe diameter and is not more than one half of the wavelength corresponding to the center frequency of the antenna.
5. A municipal concrete drainage pipe leak detection and localization method according to claim 3, wherein prior to full-wave inversion in step 2, known spatial attribute information of the drainage pipe is introduced as inversion constraints, the known spatial attribute information including one or more of horizontal position, burial depth and pipe diameter of the pipe centerline.
6. The method for detecting and positioning leakage of municipal concrete drainage pipeline according to claim 2, wherein in the step 2, a multi-frequency band joint inversion, iterative optimization or regularization constraint method can be adopted when full-waveform inversion is performed based on radar detection data.
7. The method for detecting and positioning leakage of municipal concrete drainage pipelines according to claim 2, wherein in the step 3, a dielectric constant model and a conductivity model are formed into double constraints, and the water content and the porosity of soil around the pipelines are solved in a combined mode.
8. The method for detecting and positioning leakage of municipal concrete drainage pipeline according to claim 2, wherein in the step 4, a distribution diagram of water content and porosity of soil around the pipeline is generated for visually displaying the leakage range.
9. The method for detecting and locating leakage of municipal concrete drainage pipeline according to claim 2, wherein in the step 4, after judging that the pipeline leakage exists, leakage point locating is further carried out, wherein in the three-dimensional spatial distribution of the water content and the porosity, the three-dimensional shape of an abnormal region is identified, if the abnormal region shows a local high-value core intersecting or adjacent to the pipeline on a vertical section and is discontinuously distributed along the pipeline trend on a horizontal plane, the vertical projection position of the high-value core on the pipeline center line is judged to be a potential pipeline leakage point or leakage section.
10. The method for detecting and positioning leakage of municipal concrete drainage pipelines according to claim 9, wherein in the step 4, the leakage severity index is further calculated for the position determined as the leakage point or the leakage section, the index is obtained by weighting and summing relative deviations of a water content abnormal value and a porosity abnormal value obtained by inversion at the position and a background value respectively, the positioned potential pipeline leakage point or the leakage section information is compared with a pipeline endoscopic detection result to verify, and if structural defects are found at the corresponding position by the endoscopic detection, the position is finally confirmed to be a leakage source.

Description

Municipal concrete drainage pipeline leakage detection and positioning method Technical Field The invention belongs to the field of nondestructive detection and state evaluation of underground pipeline diseases, and particularly relates to a leakage detection and positioning method for municipal concrete drainage pipelines. Background Municipal drainage pipe network is an important infrastructure of cities, and in the long-term service process, due to the influence of various factors such as material aging, uneven settlement of foundations, external load impact and the like, cracks or deformation are often generated in a pipeline body and an interface of the pipeline body, so that sewage is infiltrated outwards. The leaked sewage not only causes water resource waste and environmental pollution, but also can continuously erode backfill soil around the pipeline, weaken the structural strength of the soil, easily cause secondary disasters such as road collapse and the like, and form serious threat to urban safety and public safety. The detection and accurate positioning of the leakage hidden trouble of the drainage pipeline in time are key to preventing accidents and realizing targeted repair. The traditional detection method mainly relies on direct excavation and inspection, and has the obvious defects of large engineering quantity, high cost, road surface damage, traffic influence and the like although the result is visual, and is difficult to be suitable for large-scale pipe network health census and periodic monitoring. For this reason, various types of nondestructive testing techniques have been developed. The closed-circuit television detection technology for the pipeline can directly observe the internal condition of the pipeline, but cannot change the soil body at the periphery of the pipeline, and the acoustic detection method is sensitive to active leakage points of specific types, is greatly interfered by environmental noise, and cannot evaluate the soil body accumulation influence caused by historical leakage. The ground penetrating radar, which is a geophysical method sensitive to the electrical difference of underground media, has the characteristics of rapid detection, high resolution, no damage and the like, and has been introduced into underground pipeline detection and shallow disease investigation. The traditional application mode is generally based on data acquired by a single measuring line, and the existence of an abnormal body is qualitatively judged by analyzing the travel time, amplitude or waveform characteristics of reflected waves. However, this approach faces multiple bottlenecks in addressing the specific problem of pipe leakage. Firstly, the three-dimensional space form of a leakage influence area is difficult to reconstruct by single section data, so that the specific position of a leakage point in the longitudinal direction of a pipeline cannot be accurately judged, and the diffusion range of sewage in a soil body cannot be quantified. Secondly, the conventional interpretation method is insufficient in utilization of abundant dielectric information contained in the radar full waveform data, depends on empirical interpretation, and is poor in quantification and objectivity of inversion results. Furthermore, when the inversion interpretation is performed in a complex urban underground environment, if the information such as the accurate spatial position of a known pipeline cannot be effectively integrated as constraint, the multi-resolution of the inversion process can be obviously increased, and false anomalies or positioning deviations are easy to generate. Finally, existing methods are usually stopped at a binary judgment of "whether leakage" or not, lack of a quantitative evaluation system for correlating geophysical anomalies with engineering disease severity, and have difficulty in effectively supporting repair priority decisions in conclusion. Therefore, the prior art is not provided with a detection method which can comprehensively utilize multidimensional radar data, fuse priori information, realize accurate positioning of a three-dimensional space of pipeline leakage and quantitatively evaluate the severity of the leakage. This disadvantage limits the deep application of ground penetrating radar technology in the accurate operation and maintenance of drainage pipe network. Disclosure of Invention In order to solve the technical problems, the invention provides a municipal concrete drainage pipeline leakage detection and positioning method. The specific invention comprises the following steps: A municipal concrete drainage pipeline leakage detection and positioning method is based on full waveform data of a ground penetrating radar acquired in a non-contact manner above a pipeline, dielectric constant and conductivity distribution of soil around the pipeline are obtained through full waveform inversion, then water content and porosity distribution of the soil are obtaine