Advantages of tunnel monitoring using distributed fibre optic sensing

Abstract

Predictive maintenance and safety assessment during the construction and operational phase are becoming more and more important in modern tunnelling. However, traditional measurement methods are often time-consuming, expensive and partially require an interruption of the tunnel traffic. In this article, we present a tunnel monitoring approach based on distributed fibre optic sensing (DFOS), which delivers hundreds of strain and temperature sensing points inside the structure and gives completely new information about the behaviour of the tunnel lining. Measurements can be performed automatically without the need of access to the tunnel and hence, monitoring can be made without disturbing the tunnel construction or operation. The developed system was installed within the shotcrete tunnel lining of a railway tunnel under construction in Austria. In addition to the critical installation process, this article discusses the main monitoring results and compares them to conventional measurements.

Application of Internet of Things Based on Wireless Sensor in Tunnel Construction Monitoring

“…The results show that the tunnel construction monitoring and measurement system based on the Internet of Things can provide real-time and accurate information for the design and construction parties in the actual project, so as to ensure the requirements of project progress and safety. Internet of Things technology is a new network technology that connects various entities with various networks such as the Internet and widely obtains all kinds of information through strip QR code, radio frequency identification technology (RFID), sensor technology equipment, global positioning system, and wireless transmission technology, so as to realize comprehensive intelligence such as positioning, tracking, and monitoring and realize good communication between people and things [7,8].…”

“…(3) Before embedding, the initial frequency of the pressure box sensor shall be recorded, the sensor shall be numbered, and the corresponding connector shall be marked. Pay attention to the conductor protection during embedding 5 Journal of Sensors progress of construction, the pressure box is installed in time after the excavation of the face, the contact pressure is monitored and measured, the data of surrounding rock pressure changing with time is obtained, and the data curve is preliminarily analyzed [8,19]. The monitoring and measurement frequency shall be implemented according to Table 2 above.…”

Verteilte Rissbreitenmessung im Betonbau mittels faseroptischer Sensorik – Neue Anwendung von verteilten faseroptischen Messsystemen

“… Einbau von faseroptischen Sensorkabeln a) in Spritzbetonschalen und b) bei Tübbingen [9] Embedding of fibre optic sensing cables into a) shotcrete linings and b) tunnel lining segments [9] …”

Distributed Fiber Optic Shape Sensing of Concrete Structures

“…Distributed fiber optic sensing (DFOS) has significantly evolved in recent years to monitor large scale civil infrastructures, such as bridges [ 2 , 3 , 4 , 5 ], high-rise buildings [ 6 ], reinforced earth structures [ 7 ], pipelines [ 8 , 9 ], or tunnels [ 10 , 11 , 12 , 13 ]. The technology enables distributed, continuous strain and temperature measurements with high accuracy and high spatial resolution over kilometers, where the sensing fiber can be directly embedded inside the structure.…”

“…Table 1. Characteristics of different distributed fiber optic strain sensing systems (specifications obtained from corresponding product datasheets [31][32][33][34][35][36][37][38][39] and laboratory tests, see, e.g., in [13]).…”