Study On Bolt Stress Distribution Law Based By Fiber Bragg Grating Sensing Technology

Bolt support is widely used in geotechnical engineering supporting technology, economic,efficient, safe, determines its further application in the field of engineering. The bolt stressdistribution, is the premise of the study of bolt support theory, we also actively explore thetheoretical basis of anchoring quality monitoring method.In this paper, the current method of anchorage quality monitoring has carried on the briefintroduction, and introduced the distributed optical fiber Bragg grating monitoring method.On the basis of analysis anchor force, Optical fiber Bragg grating is proposed monitoring ofanchor stress experiment method. Studied how to simulate in the laboratory the installation ofwhole--anchored and end-anchored bolts in the engineering construction, makes boltanchoring force is generated by the rock mass, anchoring agent and bolt, and take thefeasibility test for it. Conducted two poll out experiments to the whole--anchored andend-anchored bolts in the laboratory. the experimental process paste three fiber Bragg gratingsensor on the bolt to monitoring the anchor rod strain. The periphery of the host materialadhesive five strain gages, monitoring the strain of the base body in the process of poll out.Experimental results show that the monitoring fiber Bragg grating the anchor stressdistribution law is consistent with the theoretical analysis. the host material of the strainchange and the change of the strain of the anchor rod is similar. The bolt axial forcedistribution By gaussian function fitting close to the measured figure. Through the analysis offitting coefficient, get in front of the anchor rod failure, fitting coefficient of turning point,thus by monitoring the stress distribution of anchor bolt for the anchorage quality of anchorbolt monitoring. Due to the characteristics of fiber Bragg grating monitoring system, canrealize on-line monitoring for24hours, so after can be widely used in supporting qualitymonitoring in geotechnical engineering, and can be early warning before the bolt failure.