Study On Fiber Bragg Grating Sensors For Slope Safety Monitorirg

Stability monitoring of dangerous slope along the railway directly related to the safety of railway transportation. At present, the research of slope safety monitoring is most based on electric sensors, which are vulnerable to electromagnetic interference. The output signal of electric sensors is weak current which transmission distance is restricted. As a wavelength-encoded optic fiber sensing element, fiber Bragg gratings possess of many advantages such as immunity to electromagnetic and optical power fluctuations, remote sensing, capability of multiplexing, etc. Various FBG sensors for temperature, stress and strain, displacement, vibration, and acceleration measurement have been developed and applied in engineering filed. The application of optical fiber Bragg grating in project of slope monitoring develops rapidly, and several of new research results emerging one after another. Stable and reliable FBG sensor is the root of long-term monitoring for slope safety. According to requirements of the dangerous slope safety monitoring of Guiyang-Guangzhou railway, this paper has designed and developed a serious of FBG sensors and done a lot of performance tests. Primary monitoring results have been obtained by the application of the FBG sensors in slope engineering. The content of this paper is as follows:1. Current research of slope safety monitoring at home and abroad has been introduced. Principle of fiber Bragg grating sensors has been described dentally.2. The scheme of flexible protective screening impact rock falls monitoring has been put forward. FBG sensors for force and vibration monitoring of flexible protective screening have been designed and tested.3. FBG sensors monitoring system for the self-safety of slope is proposed. Sensor for deep displacement measurement and a detachable connection structure rock bolt extensometer have been designed and tested. Aiming at the larger influence brought by different load distribution mode in measurement of Diaphragm type earth pressure sensor, a novel earth pressure sensor has been designed and tested.4. Sensor of deep displacement measurement and rock bolt extensometer have been applied in slope project, according to monitoring result, we have mastered the influence to the FBG sensors during concrete Pouring and solidification.