A landslide monitoring application is presented by using a high-resolution distributed fiber optic stress sensor. The sensor is used to monitor the intra-stress distribution and variations in landslide bodies, and can...A landslide monitoring application is presented by using a high-resolution distributed fiber optic stress sensor. The sensor is used to monitor the intra-stress distribution and variations in landslide bodies, and can be used for the early warning of the occurrence of the landslides. The principle of distributed fiber optic stress sensing and the intra-stress monitoring method for landslides are described in detail. By measuring the distributed polarization mode coupling in the polarization-maintaining fiber, the distributed fiber stress sensor with stress measuring range 0 to 15 MPa, spatial resolution 10 cm and measuring range 0.5 km, is designed. The warning system is also investigated experimentally in the field trial.展开更多
In order to quantitatively evaluate the structural safety of the heating pipeline,a real-time monitoring method for the stress state of the heating pipeline based on the distributed optical fiber sensor is proposed.Th...In order to quantitatively evaluate the structural safety of the heating pipeline,a real-time monitoring method for the stress state of the heating pipeline based on the distributed optical fiber sensor is proposed.The implementation scheme of the monitoring system is introduced.According to the mechanical mechanism of bending deformation and thermal expansion deformation of pipeline and the relationship between it and bending stress,axial compressive stress,the theoretical basis for extracting axial nominal strain and axial compressive strain using strain monitoring data to quantify the stress state of heating pipeline is established.The prototype test is carried out using a directly buried heating hot water pipe section to test the effectiveness of the method.The prototype test shows that the monitoring system can obtain the longitudinal strain curve of the working pipe in real time,extract the axial nominal strain,and realize the identification of the anchorage section and transition section of the heating pipeline.The bending stress,axial compressive stress and hoop stress of the working pipe can be quantitatively obtained by using longitudinal strain,axial nominal strain,and the monitoring data of operating temperature and internal pressure.An analysis of the monitoring data found that the maximum value of the equivalent stress may appear in the transition section,which is related to the distribution of the bending stress of the working pipe.According to the monitoring results,the structural safety of the heating pipeline can be evaluated in real time,and the operating parameters of the pipeline are revised according to the current state,which makes up for the defect that the existing monitoring methods can not truly reflect the stress state of the heating pipeline.展开更多
基金supported by the National Natural Science Foundation of China under Grant No. 60377021partially supported by Program for New Century Excellent Talents in University under Grant. No. NCET-07-0152Sichuan Scientific Funds for Young Researchers under Grant No. 08ZQ026-012.
文摘A landslide monitoring application is presented by using a high-resolution distributed fiber optic stress sensor. The sensor is used to monitor the intra-stress distribution and variations in landslide bodies, and can be used for the early warning of the occurrence of the landslides. The principle of distributed fiber optic stress sensing and the intra-stress monitoring method for landslides are described in detail. By measuring the distributed polarization mode coupling in the polarization-maintaining fiber, the distributed fiber stress sensor with stress measuring range 0 to 15 MPa, spatial resolution 10 cm and measuring range 0.5 km, is designed. The warning system is also investigated experimentally in the field trial.
文摘In order to quantitatively evaluate the structural safety of the heating pipeline,a real-time monitoring method for the stress state of the heating pipeline based on the distributed optical fiber sensor is proposed.The implementation scheme of the monitoring system is introduced.According to the mechanical mechanism of bending deformation and thermal expansion deformation of pipeline and the relationship between it and bending stress,axial compressive stress,the theoretical basis for extracting axial nominal strain and axial compressive strain using strain monitoring data to quantify the stress state of heating pipeline is established.The prototype test is carried out using a directly buried heating hot water pipe section to test the effectiveness of the method.The prototype test shows that the monitoring system can obtain the longitudinal strain curve of the working pipe in real time,extract the axial nominal strain,and realize the identification of the anchorage section and transition section of the heating pipeline.The bending stress,axial compressive stress and hoop stress of the working pipe can be quantitatively obtained by using longitudinal strain,axial nominal strain,and the monitoring data of operating temperature and internal pressure.An analysis of the monitoring data found that the maximum value of the equivalent stress may appear in the transition section,which is related to the distribution of the bending stress of the working pipe.According to the monitoring results,the structural safety of the heating pipeline can be evaluated in real time,and the operating parameters of the pipeline are revised according to the current state,which makes up for the defect that the existing monitoring methods can not truly reflect the stress state of the heating pipeline.
