Key Technologies in Urban Underground Pipeline Surveying and Data Management

Abstract: Urban underground pipelines are the "lifelines" of modern cities, encompassing various types such as water supply, drainage, gas, heating, telecommunications, electricity, and industrial pipelines. Due to their dense distribution and complex management, underground pipeline surveying involves large amounts of data, requiring a combination of multiple surveying methods. By adopting appropriate surveying techniques and data analysis models, it is possible to accurately reflect the characteristics of underground pipelines. This article explores the surveying methods and data analysis techniques used in urban underground pipeline measurement, focusing on data collection, processing, and storage. Through effective data management, work efficiency is greatly improved, and the accuracy and real-time availability of pipeline data are ensured to meet the needs of "digital city" construction.

1. Introduction

As the pace of urbanization continues to accelerate, underground pipeline systems play a crucial role in modern city infrastructure. These pipelines are responsible for the transmission of information and energy, as well as for flood control, disaster mitigation, and waste disposal. However, the distribution of these pipelines is often complex and region-specific, making their surveying and management challenging. The ability to accurately measure and effectively manage these pipelines is vital for city construction.

2. Types of Urban Underground Pipelines

Urban underground pipelines can generally be divided into two categories: urban underground pipes and underground cables. These pipelines can be further subdivided based on their purpose, material, and pipe shape:

2.1 By Purpose:

Water Supply Pipes (JS)

Drainage Pipes (PS), including rainwater (YS) and wastewater (WS)

Gas Pipes (RQ), including coal gas (MQ), liquefied gas, and natural gas

Heating Pipes (RL), including steam (ZQ) and hot water (RS)

Industrial Pipes (GY), including hydrogen (Q), oxygen (Y), acetylene (YQ), petroleum (SY), and slag removal (PZ)

Electricity Lines (DL), including power supply (GD), streetlights (LD), and electric trams (DC)

Telecommunication Lines (DX), including communications (TX), fiber optic cables (GL), broadcasting (GB), and television (DS)

Integrated Ducts (ZH)

Civil Defense (RF)

2.2 By Material:

Metal Pipes

Non-metallic Pipes, including cement pipes and plastic pipes (PPR, PVC)

2.3 By Pipe Shape:

Circular Pipes

Square Pipes

Trenches (or Ducts)

3. Key Elements of Underground Pipeline Surveying

The main task of underground pipeline surveying is to determine the installation status of various pipelines, including their projection location and burial depth. The survey results provide crucial data for the later maintenance and management of these pipelines. Pipeline points are divided into visible and hidden points:

Visible Pipeline Points: These include inspection well covers, junction boxes, telecommunication manholes, telecom handholes, etc., which make it easier to conduct field surveys and measurements.

Hidden Pipeline Points: For pipelines that are deeply buried or hard to observe directly, specialized instruments are used to detect the projection location and burial depth.

The surveying tasks mainly include:

Surface control measurements

Determining the type and specification of the underground pipelines

Detecting the position and burial depth of pipelines

Collecting the coordinates of pipeline surface projection points

Storing and validating survey results

4. Surveying Techniques for Underground Pipelines

Underground pipeline surveying is a highly technical task that involves several fields, including geophysical exploration, measurement, and data processing. To ensure the accuracy and completeness of the data, multiple techniques are often combined to adapt to different environmental and technical conditions.

4.1 Metal Pipeline Detection

The detection of metal pipelines typically relies on electromagnetic field principles. A pipeline detector transmits an electromagnetic signal, which causes alternating microcurrents in underground metal pipelines, generating a secondary electromagnetic field around the pipeline. The detector's receiving device analyzes this field distribution to locate the pipeline’s position. Common methods include:

Charging Method

Selective Excitation Method

Pressing Line Method (including horizontal, vertical, and inclined pressing lines)

4.2 Non-metallic Pipeline Detection

Detection of non-metallic pipelines is more complex and may involve methods such as:

Induction Method

High-frequency Detection Method

Excavation Method

5. Data Collection and Management

Underground pipeline data collection involves a significant amount of fieldwork, and effectively organizing and managing this data is crucial. The best way to handle and utilize this data is to establish a GIS system database for underground pipelines. By digitizing and informatizing the management, it greatly improves data processing efficiency and ensures that the pipeline information is accurate and up-to-date.

5.1 Accuracy Requirements

The accuracy of underground pipeline measurements is stringent. For different types of pipelines and burial depths, the measurement accuracy limits vary:

Accuracy for Hidden Pipeline Detection: The horizontal position limit difference is ±0.10h, and the burial depth limit difference is ±0.15h.

Accuracy for Visible Pipeline Burial Depth Measurement: When the burial depth is less than 2 meters, the limit is ±5cm; between 2 and 4 meters, it is ±8cm; and greater than 4 meters, it is +10cm.

Measurement Accuracy for Pipeline Points: The horizontal position error should not exceed ±5cm (relative to nearby control points), and the elevation error should not exceed ±3cm.

5.2 Data Storage and Management

All measurement data should be entered into an underground pipeline data processing system and stored according to the established procedures. The system automates data entry, modification, and deletion, greatly improving data management efficiency and reducing human errors.

6. Conclusion

As urban construction continues to evolve, the number and variety of underground pipelines are also increasing. Underground pipeline surveying plays a vital role in ensuring the infrastructure of "smart cities" and has significant implications for urban information management. By accurately surveying and managing underground pipelines, the integrity, accuracy, and real-time availability of data can be ensured, meeting the needs of modern "digital city" construction. Through the digital and informatized management of survey data, work efficiency is greatly improved, and data becomes more effectively available to relevant departments, ensuring the sustainable development of cities.

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