Experimental Study On Landslide Monitoring Using Warning Model Based On Composite Optic Fiber Transducer

There are a number of geological disasters in our country, according to statistics the huge economic loss and casualties were caused by geological disasters such as landslide, collapse and debris flow every year. With the continuous improvement of the monitoring method and diversified development of monitoring instrument during the past few years, many achievements in the aspect of landslide monitoring and prediction has made in our country. Although the success rate of geological disasters has improved, Average rate of correct prediction over the last ten year is 3.76%. Based on optical time domain reflection technology, our team has made a composite optical fiber transducer. Some research has carried out on performance and feasibility of composite optical fiber transducer in landslide monitoring, but warning model have not be put forward systematically and prediction function relationship between the change of the optical fiber micro bending loss and relative displacement also are not established which are not carried out experimental study in landslide monitoring.Combined with NSFC Projects based on this, the author under the guidance of tutor has carried out related research and proposed warning model of composite optical fiber transducer, establish a prediction function by the indoor experiment, mathematical fitting, numerical simulation and model test. Finally the warning model of composite optical fiber transducer is studied on the real-time warning surveillance in landslides experiment, which laid a necessary foundation on the application and popularization of composite optical fiber transducer in the future. The main research work is as follows:(1)propose warning model of composite optic fiber transducer, analyze the relationship between the variation of the bow width and the displacement of optical fiber and explore the prediction function relationship between the change of the optical fiber micro bending loss and relative displacement by pursuing three purely optical modulation structure bows slight bent tensile test;(2)overhaul the scope of application of the prediction function relationship between the change of the optical fiber micro bending loss and relative displacement based on six groups of composite fiber unit grouting body direct shear test(mortar proportion are 1:4, 1:5,1:6 and plant material are PVC plastic sheet and EPS foam) using direct shear apparatus of homemade team and validate the reliability and rationality of correct prediction function by comparing with previous team test data;(3)design large scale indoor landslide test, analyze landslide deformation under different slip surfaces using FLAC3 D numerical simulation and prepare for the subsequent landslide test of warning model of composite optic fiber transducer;(4)Combined with numerical simulation analysis, carry out two landslides test using the team homemade large-scale model tests and measure landslide parameters such as the moisture content of soil sample, heavy, cohesion, internal friction angle. Monitor slope deformation using the composite optical fiber devices, inclinometer, dial indicator and analyze test data, provide basis for reliability analysis of warning model of composite optic fiber transducer;(5)Introduce the work principle of the composite optical fiber transducer in landslide monitoring, analyze the relationship and difference of the revised forecast function, monitoring data and the results of numerical simulation, test the reliability of composite fiber optic device prediction function in landslide monitoring, analyze the landslide monitoring process and real-time warning ability of warning model of composite optic fiber transducer,explore the reliability of warning model of composite optic fiber transducer in landslide monitoring by comparing with previous team test data.