Applications of Optical Fiber Sensing Technology in Monitoring of Geotechnical Structures
The geotechnical structures will be inevitably suffered from material degradation and structural performance deterioration during the in-service operation stage. In order to acquire the on-line structural responses of each phase at the structural whole li
- PDF / 248,444 Bytes
- 9 Pages / 439.37 x 666.142 pts Page_size
- 60 Downloads / 187 Views
Introduction The optical fiber sensing technology has gained significant growth and development due to the advance of laser technology, optical fiber communication technology, modern manufacturing technology, and computer technology. In comparison with the traditional sensors, the optical fiber sensors have some unique advantages, such as small dimension, good resolution and accuracy with low loss, free from electromagnetic interference and corrosion resistance. Therefore, the optical fiber sensing technology has received much attention and is widely employed in the fields of civil engineering, mechanical engineering, and aerospace engineering. In recent years, the optical fiber sensing technology is increasing used to monitor the structural condition and behavior of geotechnical structures. Usually, the geotechnical structures are too complicated to be accurately understood because of the complexity of geological conditions and the nonlinear characteristics of soil and rock materials. In this connection, the field monitoring will play an essential role in the evaluation of safety state and performance of the geotechnical structures [1]. With the development of laser and instrument technology, the optical fiber sensing technology becomes increasingly mature by overcoming the difficulties in the practical applications. Different types of optical fiber sensors with unique features and advantages are designed and produced for the specific requirements. According to the demodulation principle, the optical fiber sensor can be categorized into different types [2], such as light intensity modulation type sensor, phase modulation type sensor, and wavelength modulation type sensor. X.W. Ye (&) T. Liu Department of Civil Engineering, Zhejiang University, Hangzhou 310058, China e-mail: [email protected] D.-F. Zhang J. Li Z.-F. Liu L. Zhang Guangdong Provincial Academy of Building Research Group Co. Ltd, Guangzhou 510500, China © Springer Nature Singapore Pte. Ltd. and Zhejiang University Press 2018 X. Bian et al. (eds.), Environmental Vibrations and Transportation Geodynamics, DOI 10.1007/978-981-10-4508-0_51
555
556
X.W. Ye et al.
In the paper, the sensing principles of three kinds of optical fiber sensors are described, and the applications of optical fiber sensors to geotechnical structures are summarized.
Principles of Optical Fiber Sensing Technology Generally, a simple optical fiber sensing system consists of a light source, an optical fiber, an optical fiber sensor, a light acceptor, and a modulator element. The optical fiber plays a role in transferring the original light to the optical fiber sensor and then transferring the signal to the light acceptor. The fiber core, cladding layer, and coating layer make up the optical fiber whose constituent is silicon dioxide. The refractive index of the fiber core is higher than the cladding layer’s by reason that the fiber core contains a small amount of impurity, germanium for instance. When written into the optical fiber, a beam of white light generates the total reflection at the inte
Data Loading...
