Abstract: To address the mechanical hazards posed by high-risk factors to long-distance pipelines, an automated stress-strain monitoring system for long-distance pipelines was developed, combining stress-strain electrical measurement technology. This system uses a strain gauge mounted on the pipeline surface to collect resistance changes caused by pipeline deformation. A data conversion processor and an automatic control box jointly amplify, convert, transmit, store, and automatically measure the data, which is then transmitted via GPRS for remote data transmission and control. This system can monitor the pipeline's stress-strain status in real time, providing a practical basis for pipeline operation and management. Keywords: Long-distance pipeline, stress-strain automatic monitoring, GPRS, data transmission Introduction Long-distance oil and gas pipelines traverse complex geological and geomorphological conditions with harsh natural environments. Pipelines are frequently affected by high-risk environments such as landslides, floods, crossings, and encroachment, which can easily cause overall displacement, local deformation, or stress concentration, leading to significant displacement stress, buckling, or creep, and in severe cases, even pipeline fracture and failure. To address the mechanical hazards posed by high-risk factors in long-distance oil and gas pipelines, and in response to the need for remote monitoring of these pipelines, this paper develops a remote mechanical monitoring system for oil and gas pipelines, incorporating stress-strain electrical measurement technology. This system can monitor the stress-strain state of pipelines in real time, providing a practical basis for pipeline operation and management. Structural Components: 1. Hardware Platform: The hardware platform consists of various sensors (strain gauges and connecting bridges), a digital-to-analog converter, an amplifier, a data acquisition unit, a shielding device, a battery pack, a lightning protection device, a wireless transmission module, and a computer. It can automatically acquire and remotely transmit resistance strain data. 2. Module Composition: The main modules of the hardware system include a strain gauge acquisition unit, an automatic control box, a wireless GPRS transmission module, a solar power supply module, a lightning protection module, and a monitoring host. The main modules of the software system include a data acquisition module, a data plotting module, a database maintenance module, an automatic alarm module, and a network control module. 3. Professional Software System: The management software has the functions of storing, analyzing, and displaying various data. Its elements include mathematical and mechanical model construction, determination of the spatiotemporal reference system, metadata input, analysis of relationships between features and layers, data acquisition, data analysis, chart analysis, spatial query, visualization, and a graphical user interface. 4. The development platform provides a mathematical and mechanical model building platform for various pipeline geographic information systems and risk environments, as well as an analysis platform and user interface based on various mechanical theories. System Functions : 1. Data Input and Preprocessing: Characteristic parameters of the monitored pipeline are input through the user interface. The raw data from the field monitoring is obtained by the data acquisition system connected to the sensors. After preliminary calculation, basic mechanical information is obtained. 2. Attribute and Parameter Management: Effective and strict organization and management are achieved through a large database system. In the relational database, different table items are interconnected through related items, providing the management system with high scalability and flexible configuration capabilities. 3. Data Batch Processing: Based on the given mechanical theories, the computer calculates and analyzes to obtain stress curves, principal stress values ​​and principal stress direction angles, soil displacement, pipeline displacement, soil pressure, and other working loads. 4. Visual Output: The operation results of the management information system can be intuitively expressed through visual graphics, images, and multimedia. 5. Linking: Alarm signal input under hazardous conditions can be directly linked to the control center, facilitating corresponding emergency measures in emergency situations. 6. Remote Monitoring: The long-distance pipeline stress-strain automated monitoring system can realize the following remote monitoring functions. (1) The system is based on a remote wireless transmission system and is equipped with a solar panel or other battery pack. No manual intervention is required. The system can perform all-weather, uninterrupted measurements in the monitoring room to ensure the real-time and reliability of the monitoring data. (2) When the system measures data, it can transmit the measurement results to the computer and store the data in the memory of the strain gauge to ensure the security of the data. (3) When the wireless transmission link cannot be established, the system can automatically collect data according to the set requirements and store the results in the memory chip of the strain gauge. The data can be retrieved at once after the line is restored. (4) The resistance strain gauge acquisition unit adopts a bus structure. Multiple acquisition units only need to be connected together on one bus and share one wireless transmission system, which greatly reduces the engineering cost. (5) The resistance strain gauge acquisition unit is designed based on a low-noise high-gain amplifier and a high-precision A/D converter. The measurement accuracy is high. The acquisition unit is equipped with a temperature sensor. With the help of temperature compensation strain gauges, the influence of temperature changes on the measurement accuracy can be reduced. 7. Data acquisition The system can realize the following data acquisition functions. (1) The sensor data acquisition software is based on the Windows platform with a full Chinese graphical interface. It is easy and intuitive to use. The database uses Paradox 7, which is stable and reliable, and easy to maintain and back up. (2) The data acquisition software is based on the server/client mode. The wireless acquisition system is connected to the server, and other computers can log in to the server in client mode to share measurement data. (3) The data acquisition software can freely set the inspection time to realize automatic monitoring of data under unattended operation. (4) The software has an over-limit alarm function. After setting the alarm threshold of the strain gauge, when the measurement data exceeds the threshold, the real-time measurement value can be sent to the designated mobile phone. (5) The measurement data results can be output to an Excel spreadsheet or a specified format for easy data analysis and processing. Working principle 1. The surface of the strain acquisition tube is a shell. In order to accurately express the stress state of the tube, strain gauges need to be pasted on the surface of the tube in the 0, 45, and 90° directions. Therefore, a three-channel strain acquisition device is used to simultaneously acquire the triaxial stress state of the tube at the measuring point. It consists of three identical strain acquisition channels, a temperature sensor, a data storage device, a power supply circuit, etc. To ensure the accuracy of the test results, a high-stability precision voltage reference source was selected, a dedicated instrumentation amplifier with an amplification factor of 100 was selected, and a 16-bit low-power converter with an I2C interface was selected for the A/D converter. To reduce the influence of the reference voltage source on the measurement results, the reference of the A/D converter was selected as the external reference voltage source of the bridge. The principle of the strain acquisition device is shown in Figure 1. In general, the surface of the pipe to be measured is regarded as a biaxial stress state. At this time, a strain rose composed of 3 strain gauges (as shown in Figure 1) is used to measure the linear strain in 3 directions respectively, and then the principal stress is determined by the generalized Hooke's law. The calculation formula is [1] 2. Data conversion processor The function of the data conversion processor is to convert the data collected by the A/D converter and temperature sensor into a unified industrial bus interface under the action of the microprocessor, and to perform data transmission, data storage, initial value setting and other operations under the instruction control of the system computer [2]. Its settings are shown in Figure 2. 3. Automatic Control Box: The automatic control box controls sensors to achieve automatic measurement and data storage. It consists of a power control circuit, a microprocessor control circuit, a clock circuit, and a communication interface. It also includes a battery interface and an external power supply interface (DC12V), allowing it to be powered by a battery or directly by AC220V mains power converted by the power module. The structural principle of the automatic control box is shown in Figure 3. 4. Wireless GPRS Module: By connecting a wireless GPRS module to the automatic control box, data transmission can be achieved using GPRS in areas with mobile network coverage, enabling remote data transmission and control. Its principle is shown in Figure 4. GPRS allows nationwide roaming without roaming fees; it is always online, billed by data usage, and is inexpensive, with no charge when there is no data communication. After the monitored equipment connects to the Internet via GPRS, the system can be monitored in real time from any location with Internet access. GPRS Working Process: When dialing up to the Internet via GPRS, the mobile company's GGSN assigns the GPRS module one IP address (static or dynamic, public or private; currently, China Mobile provides dynamic IPs). After a data center computer connects to the Internet, it is assigned an IP address. The GPRS module initiates a call to the data center's IP address via the Internet. Upon response, the data center computer establishes a TCP/IP connection, enabling communication between the data center and the GPRS module. Conclusion The study of the mechanical state of oil and gas pipelines and the development of mechanical monitoring systems is a highly complex, multidisciplinary subject involving mechanics, geography, mathematics, control science, and computer technology. Different approaches and methods are used for different high-risk factors. For a specific pipeline, the first step should be to summarize the types and degrees of high-risk disasters experienced by different pipeline sections, categorize them, and establish accurate numerical and mechanical models and disaster type databases for key high-risk areas of the selected pipeline. Based on the characteristics, frequency, and severity of the disasters, the limit risk allowable conditions for that pipeline location should be determined. Finally, based on field tests, a comprehensive remote mechanical monitoring system for the pipeline should be established. Currently, a mechanical monitoring system based on the above theories is being used for mechanical monitoring in high-risk areas of the Lanzhou-Chengdu-Chongqing pipeline and is under further improvement. The system involves multiple technologies such as the embedding of strain gauges, sensors, and data acquisition instruments, signal transmission and reception, on-site power supply, configuration of digital-analog conversion, and accurate positioning of monitoring point pipelines. The establishment and improvement of this system will fill the gap in pipeline mechanical monitoring in my country. The auxiliary software based on this system will perform real-time calculation and processing of the mechanical state of pipelines under various high-risk factors and determine the safety status of the monitoring point in real time according to the disaster type database and pipeline status (pressure, burial depth, direction, etc.) database. It will also perform timed forecasting and monitoring based on the safety evaluation status. It is a relatively complex system software. References [1] Young WC, Budynas R.G, Roark's Formulas for Stress and Strain. Printed in United States of American, 2001: 53-67. [2] Li Hua, Cheng Ruiqi Computer Control Technology Lanzhou: Lanzhou University Press, 2002: 129-154. Research on Automatic Monitoring System for Stress and Strain of Long-Distance Pipelines