Research On Perceived Pole Of Geotechnical Engineering Based On Optical Fiber Sensing Technology

Supporting pole,as the main mean of defense of the geotechnical engineering stability,its stress state and structural deformation affect the safety of all kinds of geological and geotechnical engineering directly.Distributed optical fiber sensor technology can overcome the limitations of the traditional point monitoring and can conduct continuous distributed monitoring for the object which should be measured.In this thesis,basing on the feature of distributed optic fiber senor,three kinds of sensing pole that used various kinds of packaging technology were invented from three kinds of geotechnical supporting poles.And the effectiveness of them was verified both inside and outside the laboratory.In this thesis,the following work and results carried out and obtained:(1)Based on the support pole in geotechnical engineering,beginning with the analysis of the importance and current situation of the monitoring of the support pole.The existing problems of monitoring methods were pointed out,and the basic principle of the fiber sensing technology is introduced.(2)This thesis introduces three kinds of distributed optical fiber sensing technology which are commonly used in geotechnical engineering monitoring,and puts forward the concept of geotechnical engineering sensing pole.Then,the structure of these three sensing poles:anchor rod,supporting pole and inclinometer pipe,was designed by using distributed optic fiber sensing.(3)The design of sensing anchor rod,sensing piles and sensing inclinometer pipes is introduced in detail.The indoor pull-out tests and the bending tests of the inclinometer pipe are carried out to demonstratetheir performance of sensing.They have been applied in the landslide and the static load test of pile foundation to prove that sensing poles in geotechnical engineering site is feasible.(4)According to the monitoring characteristics of the geotechnical centrifuge test,a variety of micro-sensing poles,including micro-anchor rod,micro-inclinometer pipe,micro-anti-slide piles,miniature fiber grating pressure boxes and displacement gauges were developed.According to the characteristics of the high vibration of the centrifuge,the fiber grating demodulation equipment which is suitable for the vibration test was developed.The deformation rule of the sensing poles and the model soil under different centrifugal force is obtained by the geotechnical centrifuge slope model test.The effectiveness of geotechnical centrifuge fiber monitoring system was demonstrated.(5)Based on the stability monitoring of Xuelang Mountain Slope in Wuxi,a set of sensing poles monitoring system was designed.The production and installation process of fiber grating sensing poles were introduced in detail,a wireless transmission fiber grating solution for unattended in site is developed and a solar power supply system is built in site.The monitoring system could realize the real-time monitoring of the sensing poles,analyze part of the axial force state of sensing poles,and then evaluate of the slope stability.