Layered iterative underground pipeline detection method and system for pipe gallery construction

Abstract

The invention relates to the technical field of underground engineering detection, and discloses a layered iterative underground pipeline detection method for pipe gallery construction, which comprises the following steps: step 1, arranging detection points in a to-be-detected area, and injecting a functional detection agent into the detection points to construct a physical field capable of being remotely sensed in a surrounding medium; 2, performing planar scanning on the area through a remote sensing platform to obtain physical field distribution data; and 3, identifying a potential underground pipeline based on the abnormal form in the physical field distribution data. According to the method, a detection behavior is deeply embedded into a layered excavation procedure through a pioneering'layered iteration 'detection mode, a dynamic closed loop of'guiding excavation by detection, excavation verification and creating a working face for subsequent detection' is formed, and fundamental transformation from'one-time delivery of static drawings' to'whole-process dynamic perception and active safety control 'is realized; and the safety risk caused by information lag or unknown conditions at the construction stage is thoroughly eliminated.

Description

Technical Field

[0001] This invention relates to the field of underground engineering detection technology, and more specifically, to an iterative detection method and system for underground pipelines that is carried out in conjunction with layered excavation construction. Background Technology

[0002] In urban underground space development, especially in linear engineering projects such as integrated utility tunnels and deep foundation pits, accurately identifying existing underground pipelines is a crucial prerequisite for ensuring construction safety. Current technologies typically only conduct a one-time, comprehensive survey using technologies such as ground-penetrating radar before the project begins.

[0003] This method has the following drawbacks: First, for pipelines buried at greater depths, the detection signal attenuates significantly, posing a risk of missed detections. Secondly, the results of the one-time exploration were seriously disconnected from the dynamic layered excavation process, resulting in the construction team still facing the "unknown" strata that had not been explored in the subsequent excavation stage, which posed a very high safety risk. Furthermore, traditional methods struggle to balance efficiency, accuracy, cost, and environmental adaptability when dealing with long-distance, large-scale pipeline surveys.

[0004] Therefore, there is an urgent need in this field for a pipeline detection method and system that can be coupled with the depth of layered excavation and iteratively carried out, so as to achieve a fundamental transformation from static exploration to dynamic perception and proactive safety control. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing underground pipeline detection methods in layered excavation projects such as utility tunnels, including the disconnect between detection and construction, low efficiency, high risk of missing deep pipelines, and poor adaptability to complex environments. This invention provides a layered iterative underground pipeline detection method and system. This method embeds the detection process into the excavation workflow and utilizes a combination of actively constructed physical fields and remote sensing technology to achieve fully dynamic, efficient, and safe monitoring of the entire construction process.

[0006] This invention proposes a layered iterative method for detecting underground pipelines in utility tunnel construction, comprising the following steps: Step 1: Deploy detection points in the area to be detected and inject functional detection agents into them to construct a physical field in the surrounding medium that can be remotely sensed; Step 2: Perform an area scan on the region using a remote sensing platform to obtain physical field distribution data; Step 3: Identify potential underground pipelines based on the abnormal patterns in the physical field distribution data; Step 4: Conduct close-range, detailed detection and verification of the identified potential pipeline areas; Step 5: Use the verified pipeline distribution information to guide the layered excavation construction; Step 6: After the current layer is excavated, repeat the above steps on the new working face for iterative exploration; By injecting a detector to actively construct a physical field, the problem of the small difference in physical properties between pipelines and the surrounding medium under natural conditions, making remote sensing difficult, is solved. Then, area scanning is used to achieve efficient surveys, and fine verification ensures detection accuracy. The layered iterative mode embeds detection into the construction process, forming a dynamic closed loop of "detection-excavation-re-detection", which completely eliminates the risk of information lag during the construction stage, while shortening the deep detection distance and improving the reliability of deep pipeline detection.

[0007] As a further optimization of the present invention, the functional detector is a temperature difference detector, which includes a main cooling component and a long-lasting stabilizing component. The main cooling component includes urea or ammonium nitrate. The main cooling component generates a significant temperature difference, providing a clear signal for remote sensing identification. The extended-effect stabilizing component includes at least one of calcium chloride, glycerol, ethylene glycol, sodium carboxymethyl cellulose, and xanthan gum. The extended-effect stabilizing component prolongs the duration of the temperature difference and ensures the detection window period. To optimize thermal imaging recognition, consider adding signal enhancement components: materials that can improve thermal radiation contrast in small amounts, such as nano zinc oxide and carbon black, can be used to enhance thermal radiation contrast and optimize recognition performance. By combining the above functional components in a reasonable way, a long-lasting temperature difference detection agent that meets the requirements of the method of the present invention can be formulated. Moreover, the formula has high compatibility, does not require a specific ratio, is suitable for different geological environments, and is environmentally friendly, avoiding secondary pollution of groundwater and soil.

[0008] As a further optimization of the present invention, the detection points are arranged in a single-sided quincunx pattern, with a single row of detection points arranged along one side of the road, the point spacing being 1.5-2.5 meters, and transverse detection sections are set at intervals. Single-sided deployment reduces the impact on road traffic, lowers operational risks and indirect costs. The 1.5-2.5 meter point spacing, combined with the diffusion radius of the detector, forms an overlapping zone to ensure full detection coverage. The lateral detection cross section supplements the directional blind spots of the longitudinal deployment, forming a spatial cross network that improves the comprehensiveness and accuracy of detection.

[0009] As a further optimization of the present invention, the transverse detection cross-section is arranged perpendicular to the road direction, the point spacing on the cross-section is 1.5-2.5 meters, covering the full width of the road, and the transverse cross-section spacing is 80-120 meters. The cross-section layout perpendicular to the road direction ensures full coverage and avoids missing pipelines on both sides of the road. The 1.5-2.5 meter cross-section point spacing ensures continuous detection within the cross-section, while the 80-120 meter cross-section spacing balances efficiency and accuracy, reducing workload and effectively verifying longitudinal detection results, thus improving overall detection reliability.

[0010] As a further optimization of the present invention, the remote sensing platform is a drone equipped with a thermal imaging instrument, with a flight altitude of 50-100 meters, a heading overlap rate of not less than 70%, and a flight speed of 3-8 meters per second; UAV remote sensing enables rapid area scanning, improving efficiency by more than 60% compared to traditional line scanning. A flight altitude of 50-100 meters balances detection range and accuracy, and a forward overlap rate of no less than 70% ensures continuous and complete data. A flight speed of 3-8 meters per second adapts to different detection area requirements, balancing efficiency and data quality.

[0011] As a further optimization of the present invention, the abnormal morphology identification includes identifying temperature anomalies that are linearly or strip-shaped and meet at least one of the following conditions: three or more consecutive detection points show temperature anomalies with the same direction; the temperature changes between adjacent anomaly points show a regular distribution. Linear or strip-shaped anomalies are typical characteristics of pipelines, distinguishing them from point / block anomalies in areas without pipelines. The criteria of continuous detection points with anomalies in the same direction and regular temperature changes transform qualitative judgment into quantifiable intelligent identification, reducing human error and improving identification accuracy and reproducibility.

[0012] As a further optimization of the present invention, the close-range fine detection adopts ground penetrating radar, and obtains the burial depth and pipe diameter parameters of the pipeline by analyzing the two-way travel time and amplitude characteristics of the radar echo signal. Ground-penetrating radar can accurately verify suspected areas, supplementing the missing parameters of remote sensing detection. Two-way travel time and amplitude characteristic analysis can accurately obtain key parameters such as burial depth and pipe diameter, providing detailed data for construction protection and forming a technical closed loop of "survey-verification".

[0013] As a further optimization of the present invention, the method further includes a drilling step, with a drilling diameter of 30-50 mm and a drilling depth required to penetrate the hardened surface layer and then extend 15-25 cm. A borehole diameter of 30-50 mm is used to adapt to the injection of the probe, balancing injection efficiency and borehole wall stability. It penetrates the hardened layer and extends 15-25 cm, ensuring that the probe can be injected into the effective underground medium layer, avoiding the influence of the surface layer on the diffusion effect, and ensuring the quality of the physical field construction.

[0014] As a further optimization of the present invention, the single-hole injection volume of the temperature difference detection agent is 400-600 ml, and the injection process adopts a staged control strategy, first rapidly injecting 60-80% of the detection agent, and then slowly injecting the remaining part. A single-well injection volume of 400-600 ml can form a physical field of sufficient range to meet the needs of remote sensing identification. In the staged injection strategy, rapid injection ensures that the probe reaches the bottom of the well, while slow injection promotes uniform diffusion, avoids local accumulation, and improves the stability and continuity of the physical field distribution.

[0015] A layered iterative underground pipeline detection system for utility tunnel construction, used to implement the above-mentioned detection method, includes: The detection point and drilling device is used to set up detection points and complete drilling in the area to be detected. A probe injection device is used to inject functional probes into the borehole; Remote sensing platforms are used to perform area scanning to acquire physical field distribution data; The data processing unit is used to process physical field data and identify pipeline anomalies; The sophisticated verification equipment is used for close-range detection and verification of suspected pipeline areas; The system's components have clear division of labor and work together to achieve full automation of the entire process from site selection, injection, scanning, identification to verification. Moreover, the equipment is lightweight and flexible, highly adaptable to narrow, sensitive, or load-bearing construction areas, eliminating the need for large equipment, reducing the operational threshold and environmental impact, and meeting the requirements of green construction.

[0016] The core principle of this invention lies in "actively constructing a physical field and remotely identifying abnormal patterns". Under natural conditions, the physical properties of underground pipelines and the surrounding medium are very similar and difficult to be remotely sensed. This invention actively and forcibly constructs a stable and persistent detectable physical field (such as temperature field, electromagnetic field, etc.) in the medium by injecting functional detection agents underground. The distribution pattern of this physical field is directly affected by the underground geological structure. In areas without pipelines, the physical field forms a roughly regular anomalous zone (such as a circular low-temperature patch) centered on the injection point. In areas with pipelines, because the backfill soil around the pipeline is usually looser or has a different structure than the original soil, a "preferred seepage or diffusion path" will be formed. The probe will preferentially migrate along the pipeline and eventually project a continuous, linear anomalous zone (such as a linear low-temperature strip) on the surface. Therefore, by using remote sensing platforms (such as drones) to perceive the physical field distribution on the Earth's surface and identifying the morphological differences between linear anomaly zones and point / block anomalies, the existence and direction of underground pipelines can be determined efficiently and accurately. Based on this, ground-penetrating radar and other technologies can be used to conduct close-range fine detection and verification of suspected areas, forming a complete technical closed loop of "active identification, area survey, and precise verification".

[0017] The layered iterative underground pipeline detection method and system for utility tunnel construction proposed in this invention have the following beneficial effects: (i) By pioneering the “layered iterative” detection mode, the detection behavior is deeply embedded in the layered excavation process, forming a dynamic closed loop of “detection guiding excavation, excavation verification and creating working face for subsequent detection”. This realizes a fundamental transformation from “one-time delivery of static drawings” to “full-process dynamic perception and proactive safety control”, and completely eliminates the safety risks caused by information lag or unknown situations during the construction stage. (ii) By adopting the strategy of “constructing physical fields by setting up points + remote sensing area survey”, the traditional line scanning mode of geophysical exploration is upgraded to an efficient area scanning mode. As verified by engineering practice, this strategy can improve the survey efficiency by more than 60%. At the same time, because the operation is concentrated in a single-sided safe area, the reliance on large equipment and closed roads is reduced, the impact of the exploration operation on road traffic is minimized, indirect costs are significantly reduced, and the balance between efficiency and safety is achieved. (iii) By directly probing the next layer from the new working face after each layer is excavated, the detection distance is greatly shortened, the signal attenuation problem is effectively overcome, and the detection accuracy and reliability of deep pipelines are significantly improved. (iv) The use of functional detection agent system and lightweight remote sensing platform has better adaptability to narrow, sensitive or limited load-bearing construction areas compared with physical detection equipment that relies on large vehicles. At the same time, its environmentally friendly characteristics avoid secondary pollution of groundwater and soil, and meet the requirements of green construction. (v) In the intelligent identification stage, by introducing the "signal morphology continuity analysis" criterion, a comprehensive interpretation algorithm based on continuous point sequences, morphological features, and temperature distribution patterns was constructed. This transforms the originally qualitative image interpretation process, which relied on the personal experience of experts, into a quantifiable and replicable intelligent identification process, representing a significant advancement in the innovative application of image recognition technology in the field of underground pipeline interpretation.

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] Figure 1 The flowchart of the entire hierarchical iterative detection process provided by this invention; Figure 2 This is a plan view of the detection points provided by the present invention; Figure 3 This is a schematic diagram illustrating the working principle of the detector provided by the present invention. Detailed Implementation

[0020] Embodiments of the present invention are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar symbols denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0021] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0022] Please see Figures 1-3 This embodiment focuses on a newly constructed underground utility tunnel project in a certain city, with a total length of 1 kilometer. The tunnel is designed to have an excavation depth of 9 meters and is constructed using the open-cut method in three layers, with each layer having an excavation depth of 3 meters. To implement this invention, the project is first divided into two standard work sections: K0+000 to K0+500 is the first work section, and K0+500 to K1+000 is the second work section. Each work section independently executes the entire process of this method, as detailed below: (1) Implementation process of the first work section (K0+000 to K0+500) 1. Exploration and excavation of the first layer (original surface layer) 1.1 Detection Point Layout On the original ground surface, along the sidewalk on the west side of the utility tunnel axis, a single-row quincunx pattern of points was used for surveying and setting out, with a longitudinal point spacing of 2.0 meters. At the same time, six transverse detection sections were set up at K0+100, K0+200, K0+300, K0+400 within the section, as well as at the beginning of the section K0+000 and the end of the section K0+500. The point spacing of the sections was also 2.0 meters, covering the entire width of the road. A total of about 250 longitudinal points and about 24 transverse points were set up in this section. The technical safeguards for this deployment plan include: Longitudinal continuous coverage: By using a 2.0-meter point spacing and a 1.5-2.0-meter diffusion radius of the detector, an overlap zone of ≥0.5 meters is formed between adjacent detection points to ensure longitudinal continuous coverage; Lateral cross-validation: The lateral cross-section and the longitudinal point layout form a spatial cross network, eliminating directional blind spots; Safety measures: All operations are conducted in a safe area on one side of the road to avoid the risks associated with working on the motor vehicle lane; 1.2 Drilling Operations Use a light gasoline-powered drilling rig equipped with a 40 mm diameter hollow auger bit to drill holes at all designated locations. The required drilling depth is: after penetrating the asphalt pavement layer and the underlying stable soil layer, extend vertically downwards for 20 cm. The hole depth error should be controlled within ±3 cm, and the positioning deviation should not exceed 5 cm. 1.3 Detector Preparation and Injection Preparation: On-site preparation of functional temperature difference detection agent: Urea (main cooling component), calcium chloride (hygroscopic and long-lasting stabilizing component) and a small amount of xanthan gum (tackifying and stabilizing component) are dissolved in water in a certain proportion and stirred to form a homogeneous solution. The core functional indicator of this formulation is that it can form an effective temperature difference field that lasts for 4-6 hours after injection. Injection: Using a dedicated pressurized injection device, inject 500 ml per well as a standard dose and adopt a phased control strategy: first inject about 350 ml (70%) at a higher flow rate to ensure that the liquid reaches the bottom of the well, and then inject the remaining 150 ml (30%) at a lower flow rate to promote the uniform penetration and diffusion of the probe in the surrounding soil. 1.4. UAV thermal imaging scanning Two hours after all sites were filled (within the effective window of the probe), a drone equipped with an RTK positioning module and an infrared thermal imager was launched for operation. The flight parameters were set as follows: flight altitude 70 meters, heading overlap rate 80%, and flight speed 5 meters / second. The drone was used to conduct a full-coverage aerial photograph of the first operation section and collect surface temperature field data. 1.5 Intelligent Recognition and Accurate Verification Intelligent identification: The thermal imaging data is interpreted using the "signal morphology continuity analysis" criterion, and three key features are analyzed: abnormal morphological features (distinguishing between linear stripes and circular patches), temperature difference anomaly sequences with the same direction appearing at three or more consecutive detection points, and the regularity of temperature changes between adjacent anomaly points. Two clear, continuous linear low-temperature anomaly bands were identified near K0+150 and K0+380. Precise verification: A 400MHz high-frequency ground-penetrating radar was then used to perform a detailed scan of the aforementioned anomaly zone. By analyzing the two-way travel time and amplitude characteristics of the radar echo signals, the verification results were confirmed. The anomaly at K0+150 is a DN300 water supply PVC pipe buried at a depth of 1.8 meters; The anomaly at K0+380 is a DN500 concrete rainwater pipe buried at a depth of 2.2 meters; 1.6 Deliverables and Safe Excavation The verified pipeline distribution map is imported into the construction management system. Based on the detection results, the machinery and equipment are directed to carry out the first layer of earthwork excavation, excavating to the design elevation of -3.0 meters in one go. During the excavation process, the locations of the pipelines that have been detected are closely monitored, and after they are exposed, they are immediately supported, protected or relocated in accordance with the specifications.

[0023] (2) Exploration and excavation of the second layer (the working surface layer of the first foundation pit) 2.1 After the first layer of earthwork excavation and pipeline treatment of the first working section are completed, a new working face shall be established on the bottom surface of the formed -3.0-meter foundation pit; 2.2 On this new working face, repeat the entire process of operation (spotting, drilling, grouting, scanning, identification, and verification). The target depth range of this exploration is the second layer of soil to be excavated, that is, from the current working face (-3.0 meters) to -6.0 meters; The detection points are laid out using a single-sided quincunx pattern, with the longitudinal point spacing remaining at 2.0 meters. Three transverse verification sections are laid out based on the on-site working conditions. 2.3 During this round of exploration, a previously undiscovered communication cable duct group with a burial depth of 4.5 meters was discovered near K0+250. Based on this result, mechanical equipment was directed to carry out the second layer of earthwork excavation, excavating to the design elevation of -6.0 meters in one go, and the protection work of the cable duct group was completed simultaneously.

[0024] (3) Implementation of the second work section (K0+500 to K1+000) After completing the excavation and exploration of all designed depths in the first working section, move to the second working section and repeat all the above steps. During the implementation of the second working section: approximately 250 longitudinal points and 6 transverse sections were set up, and 3 underground pipelines were discovered and verified (2 power lines and 1 communication line). The three-layer iterative exploration and excavation were completed according to the same process.

[0025] In the detection of a 1-kilometer utility tunnel in this embodiment, the method of the present invention successfully detected and verified 7 underground pipelines, including 5 non-metallic pipelines. The entire detection process was closely coordinated with the construction excavation, forming a complete dynamic safety control closed loop. Compared with the traditional full-line ground penetrating radar scheme, the survey efficiency was improved by about 60%, and the indirect cost was reduced by about 50% because it avoided the frequent relocation of large radar equipment and road closures. This fully demonstrates the comprehensive advantages of the present invention in terms of efficiency, cost and safety.

[0026] In summary, this invention, through a layered iterative detection mode, embeds detection depth into the construction process, forming a dynamic closed loop and completely eliminating the risk of delayed construction information. It proactively constructs a combination of physical field and remote sensing area scanning, significantly improving detection efficiency and reducing traffic impact. Layered detection shortens the detection distance for deep pipelines, overcomes signal attenuation problems, and improves detection accuracy. Functional detection agents and lightweight equipment are adaptable to complex environments, making it environmentally friendly and cost-effective. Intelligent identification criteria enable quantitative interpretation, reducing human error. The overall method and system realize the transformation of underground pipeline detection from static to dynamic, from line scanning to area scanning, and from experience-based interpretation to intelligent identification, making it suitable for full-process safety monitoring of layered excavation projects such as utility tunnels.

[0027] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A layered iterative underground pipeline detection method for use in construction of a pipe rack, characterized by, The method comprises the following steps: Step 1: arranging detection points in the area to be detected and injecting functional detection agent into the detection points to build a physical field in the surrounding medium that can be remotely sensed; Step 2: performing surface scanning on the area by a remote sensing platform to obtain physical field distribution data; Step 3: identifying potential underground pipelines based on abnormal patterns in the physical field distribution data; Step 4: performing close-range fine detection verification on the identified potential pipeline area; Step 5: using the verified pipeline distribution information to guide layered excavation construction; Step 6: after the current layer is excavated, repeating the above steps on the new working surface for iterative detection.

2. The layered iterative underground utility mapping method for pipe rack construction of claim 1, wherein, The functional detection agent is a temperature difference detection agent, which comprises a main cooling component and a delayed stable component. The main cooling component comprises urea or ammonium nitrate, and the delayed stable component comprises at least one of calcium chloride, glycerol, ethylene glycol, sodium carboxymethyl cellulose, and xanthan gum.

3. The layered iterative underground utility mapping method for use in pipe rack construction of claim 1, wherein, The detection points are arranged in a single-sided cluster point arrangement, with a single row of detection points arranged on one side of the road, a point distance of 1.5-2.5 meters, and transverse detection sections arranged at intervals.

4. The layered iterative underground pipeline detection method for pipe rack construction of claim 3, wherein, The transverse detection sections are arranged perpendicular to the road direction, with a point distance of 1.5-2.5 meters on the section, covering the full width of the road, and a transverse section distance of 80-120 meters.

5. The layered iterative underground utility mapping method for use in pipe rack construction of claim 1, wherein, The remote sensing platform is a drone carrying a thermal imaging instrument, with a flight height of 50-100 meters, a heading overlap rate of not less than 70%, and a flight speed of 3-8 meters / second.

6. The layered iterative underground utility mapping method for use in pipe rack construction of claim 1, wherein, The abnormal pattern identification includes identifying temperature anomalies that are linearly or strip-shaped distributed, and satisfying at least one of the following conditions: Temperature difference anomalies in the same direction appear at three or more consecutive detection points; The temperature change between adjacent abnormal points shows a regular distribution.

7. The layered iterative underground utility mapping method for use in pipe rack construction of claim 1, wherein, The close-range fine detection uses ground penetrating radar to obtain pipeline burial depth and pipe diameter parameters by analyzing the two-way travel time and amplitude characteristics of radar echo signals.

8. The layered iterative underground utility mapping method for use in pipe rack construction of claim 1, wherein, The method further comprises a drilling step, with a drilling diameter of 30-50 millimeters and a drilling depth requirement of extending 15-25 centimeters after penetrating the surface hardening layer.

9. The layered iterative underground utility mapping method for use in pipe rack construction of claim 2, wherein, The single-hole injection amount of the temperature difference detection agent is 400-600 milliliters, and the injection process uses a phased control strategy, with 60-80% of the detection agent injected quickly first, and the remaining part injected slowly.

10. A layered iterative underground pipeline detection system for use in the construction of a pipe rack for use in carrying out the detection method of any one of claims 1 to 9, characterised in that, The method comprises: A point arrangement and drilling device for arranging detection points in the area to be detected and completing drilling; A detection agent injection device for injecting functional detection agent into the drill hole; A remote sensing detection platform for performing surface scanning to obtain physical field distribution data; A data processing unit for processing physical field data and identifying pipeline anomalies; A fine verification device for close-range detection verification on suspected pipeline areas.

Images