Launch of a national key R&D project related to fiber optic sensor applications

[ Instrument Network Instrument Development ] On October 10th, a national key research and development project specifically addressing the safety of urban underground infrastructure operations was launched in Wuhan. The project plans to introduce fiber optic sensors to achieve comprehensive monitoring and early warning of urban underground infrastructure such as subway tunnels.

The project will focus on key areas of urban underground infrastructure monitoring, data map

It is understood that the project is called "Research and Demonstration of Key Technologies for Comprehensive Monitoring of Urban Underground Infrastructure Operation", led by China Railway Fourth Survey and Design Institute Group Co., Ltd., and 14 units including Huazhong University of Science and Technology and Wuhan University to realize the joint study of production, education and research. Research and demonstration applications.

Urban underground infrastructure includes subway tunnel sections, underground complexes, and underground integrated pipe corridors. These facilities have disaster risks such as floods, fires, deformation of underground structures, leakage, and cracking. For example, the running subway is suddenly hit by foreign objects, and the underground pipe gallery encounters the situation of flooding Jinshan. How to prevent these underground disasters that may occur?

According to Qiu Shaofeng, chief engineer of the Equipment Department of the Fourth Institute of Iron and Steel, at present, the domestic monitoring methods mainly use sensor technology to monitor each field separately. For example, floods, fires, etc. are monitored separately, and afterwards, it is difficult to achieve urban safety. And efficient integrated management.

Urban subway tunnel, data map

For example, the traditional subway safety monitoring methods include total station, level, electric point sensor and manual inspection, etc., and the human interference factor is large. Therefore, the traditional safety monitoring method can not effectively meet the needs of subway safety monitoring. At the same time, the conditions of the subway working conditions are complex, and a monitoring method with good stability, high reliability, strong real-time and anti-electromagnetic interference is urgently needed.

Qiu Shaofeng said that the project plans to build a new comprehensive monitoring system for urban underground infrastructure. Once an abnormality occurs in the underground infrastructure, timely warning, real-time monitoring and scientific decision-making can be provided. This is equivalent to attaching a sensitive neural sensing system to the underground infrastructure. The inanimate infrastructure can also sense and transmit information, thus providing intelligent and comprehensive decision-making.

To this end, the project plans to introduce fiber optic sensors to achieve 24-hour continuous monitoring, to detect small changes that are invisible to the human eye, and to provide early warning. Taking the subway section tunnel as an example, the fiber optic sensor is placed in the tunnel, and subtle changes such as deformation and settlement of the tunnel are monitored. According to the target plan, after three years, the series of results will be demonstrated and applied in Shenzhen, Wuhan, Nanjing and other big cities.

Fiber Optic Sensor Technology and Application Introduction

Optical fiber sensing technology is a new type of sensor technology. As a new technology in recent years, optical fiber sensors can transmit, refract and absorb light, optical Doppler effect, sound and light, electro-optic, magneto-optical and elastic light. The effect, etc., causes the parameters such as the amplitude, phase, polarization state, and wavelength of the light wave to change directly or indirectly, so that the optical fiber can be used as a sensitive component to detect various physical quantities.

Fiber optic sensor in tunnel settlement monitoring application, data map

At present, fiber optic sensors have been widely used in power grid systems, road monitoring, rail transit, food safety, etc. due to their high sensitivity and precision, immunity to electromagnetic interference, high dielectric strength, corrosion resistance, and compatibility with digital communication systems. .

In the field of road safety, the fiber-optic sensing system is embedded in the cement structure to form the ability to sense stress and fracture damage. For example, the tension sensor can be used to monitor the local deformation of the tunnel where the collapse is easy. This information can be combined with the Internet to achieve Long-term, stable, real-time monitoring of these infrastructures reduces accidents.

In addition, in the field of rail transit, fiber optic sensors can also be used to collect train operating status information, high-speed comprehensive inspection trains, rail flaw detection, orbit state remote monitoring, indoor and outdoor environmental integrated sensing applications.