Research On Structural Safety Monitoring Of FBG Sensor In Slope Engineering

At present, the development of strain sensing technology has been very mature, because the strain is relatively easy to detect physical quantities. Strain Slope is also an important physical security monitoring. The long-term goal is to build highway slope, with the accelerated increase in the number of highway slope engineering and construction speed, slope protection requirements increasingly high slope safety monitoring requirements will be higher. Slope deformation, landslides and other significant features of slope failure, so for Slope strain monitoring is of great significance. Currently, most of the highway slope domestic stabling are varying degrees of quality. Therefore, timely and effective monitoring of highway slope safety information, the quality problems that may occur and highway slope to predict accurately and timely, can guarantee the safe operation of the slope, slope disease cost savings, with significant economic and social benefits.Large-scale construction of fiber Bragg grating sensor has a strong anti-electromagnetic interference capability, wide measurement range, the transmission loss, high accuracy and real-time, and other characteristics, especially suitable for the needs of real-time multi-parameter monitor (strain, temperature, vibration), such as dams, tunnels, bridges, roads. Geology traditional detection techniques can be proven road stress distribution inside the slope and slope, but it is difficult to realize the internal slope performance degradation process monitoring and disease forecasting, while monitoring the process of transportation cause significant interference. Therefore, the embedded fiber Bragg grating sensors to monitor the internal bore not only get the detailed structure of the stress field, but you can get the performance of the internal process of change of slope, and to predict future events, which can ensure long-term stability and accuracy of monitoring systems sex.Based on a slope of a secondary road Lan cang quality monitoring project background, to carry out applied research of fiber Bragg grating sensing technology in Landslide Monitoring. Includes the following aspects:1. Research and analysis of the FBG temperature sensor, the sensor structure embedded FBG strain sensors, sensor model and sensing principle, easy to use FBG sensors sensor network consisting characteristics, these several FBG sensors sensor network, to achieve long-term monitoring of the operation of the slope of the road construction, and the disease may appear to predict alarm.2. Site slope deformation analysis, landslides, the overall geology of the slope conditions and internal stress distribution were analyzed, studies have shown that the strain sensor is installed in a different location each slope monitoring holes can be achieved on the road internal stress distribution and the overall performance of the slope changes in the slope of the long-term process monitoring, to ensure slope stability and security operation. Meanwhile, the analysis of the changes of the slope of the temperature, temperature compensation in each of the monitoring hole2m,19.39m,29.45m location for the temperature sensor to reduce the effect of temperature on the accuracy of the FBG sensor.3. For the slope to a large number of field measurement time data associated with the use of a mathematical model to convert the value of the wavelength of the FBG sensor is fed back into the measured parameter value, such as strain and intuitive graph showing changes in the parameters measured process for stabilizing the security situation to determine the slope provide evidence.4. Nonlinear regression analysis using the method of monitoring data fitting analysis, first, respectively, logarithmic functions, exponential and hyperbolic functions for optical fiber monitoring data were fitted by analyzing and comparing the best fitting results logarithmic functions, can well reflect the trend of development, provide the basis for judging the structural stability of the slope. By logarithmic function for each section of the tunnel model fitting analysis, practice shows that this method can change the structure of the slope of the trend to judge, and the law of displacement and destruction of information, such as the slope landslides may occur early warning forecast.