Application Research on the Fiber Bragg Grating Sensing Technology in Arch Dam Model Test

Abstract

Abstract Fiber Bragg Grating (FBG) has the advantages of high sensitivity, high resolution, low cost and small volume. Therefore, FBG sensing technology is widely used in the monitoring of structural engineering. In this research, FBG sensing technology was applied in the geo-mechanical model test of arch dam for the first time. The geomechanical model of Lizhou arch dam was built, and the FBG sensors were arranged on the upstream dam surface, while the resistance strain gauges were arranged on the downstream dam surface. The model failure test was carried out to get the stress-strain state and its changing process of the dam body. The test results show that the monitoring results of the FBG sensors and the resistance strain gauges are basically consistent, and it is found that the initial cracking overloading safety coefficient is K 1 = 1.4 ∼ 2.2, the nonlinear deformation overloading safety coefficient is K 2 = 3.4 ∼ 4.3, the ultimate overloading safety coefficient is K 3 = 6.0 ∼ 6.6. The application of FBG technology provides a method to solve the problem that the strain of the upstream surface of the arch dam model cannot be directly monitored due to the insufficient space caused by the installation and loading system, and also provides a new idea for the measurement technology in the geo-mechanical model test.