Research on Three-Dimensional Stress Monitoring Method of Surrounding Rock Based on FBG Sensing Technology

Abstract

Research on the stress state of rock mass is essential for revealing the distribution characteristics and evolution law of the surrounding rock stress field in the roadway, studying the coal–rock dynamic disaster and the design of roadway support. This thesis proposes a three-dimensional stress monitoring method for surrounding rocks based on fiber Bragg grating (FBG) sensing technology and a cube-shaped three-dimensional stress fiber grating sensor is developed based on the principle of this monitoring method. According to the fiber grating strain obtained by numerical simulation, the calculated three-dimensional stress value is basically consistent with the theoretical value. The margin of error was plus or minus one percentage point. The sensing performance of the sensor was tested using a uniaxial compression experiment instead of a triaxial compression experiment. The experimental results show that in the range of 0~50 Mpa, the sensor’s sensitivity to X, Y and Z axis stress is 25.51, 25.97 and 24.86 pm/Mpa, respectively. The relative error of measured stress is less than 4%. Meanwhile, the sensor has good linearity and repeatability, and has broad application prospects in the field of underground engineering safety monitoring such as in coal mines and tunnels.

Application of FBG Sensor to Safety Monitoring of Mine Shaft Lining Structure

“…The fiber Bragg grating (FBG) sensor is a type of fiber grating strain that is formed by changing the refractive index of the fiber core to produce small periodic modulation [27,28]. When the temperature or stress conditions change, the fiber produces axial strain, which increases the grating period and decreases the radius of the fiber core and cladding.…”

Development of multi-sensors fusion monitoring system for shaft wall deformation

“…Real-time monitoring technology has the advantages of promptly discovering shaft wall deformation and providing accurate monitoring data. The primary method for real-time monitoring is the construction of an online monitoring system using fiber optic grating sensors and real-time communication technology [7][8][9]. However, real-time monitoring requires more equipment and maintenance costs, as well as a more complex system that necessitates the involvement of professional personnel for installation, maintenance, and data analysis.…”

Discontinuous Deformation Monitoring of Smart Aerospace Structures Based on Hybrid Reconstruction Strategy and Fiber Bragg Grating

“…Nevertheless, the majority of these techniques are geared toward offline deformation monitoring in terrestrial environments and have limitations when it comes to real-time monitoring of aircraft structural deformation. With recent advancements in distributed strain sensing techniques like Fiber Bragg Grating (FBG) sensors, strain-based deformation sensing techniques have drawn considerable interest in aerospace; the strain sensors can fulfill the requirements for lightweight design, precision, and online monitoring in aerospace [ 5 ]. Meanwhile, optical frequency domain reflectometry (OFDR) can provide more comprehensive strain data across the entire structure and is also competitive in shape sensing [ 6 , 7 , 8 ].…”