###### Abstract
The magnetic measurement method [15; 16; 17; 18; 19; 20] utilizes the magnetostrictive effect of ferromagnetic materials, reflecting the internal stress magnitude by measuring changes in magnetic permeability at various points along the anchor cable under different stress states; the advantages and disadvantages of the magnetic measurement method are summarized as follows:  
Advantages: (1) No mechanical contact with the measured component, meaning that it does not affect the load on the component and avoids sensor overload issues. (2) It directly measures the actual stress value of the component, making it suitable for online stress monitoring of in-service structural components. (3) High accuracy with measurement errors less than 2%, a simple sensor design, strong environmental durability, and a long lifespan. Disadvantages: (1) For in-service structures, this method requires on-site winding of coils, which is time-consuming and labor-intensive. The quality of the wound coil is difficult to control, and its reliability is average. (2) Current magnetic flux sensors use measuring coils for signal integration, which takes a long time. The maximum sampling frequency is 0.1 Hz, meaning that real-time monitoring is not possible, and dynamic stress variations in structural vibrations cannot be detected. The measuring coil must be wound uniformly and with a sufficient number of turns, or else the measurement accuracy and efficiency will be compromised. However, if the turns are too many, the inductance of the coil changes with the circuit, introducing interference and noise into the output signal. This requires detailed design analysis. Furthermore, to ensure that the measuring coil produces a sufficiently sensitive signal and improves the signal-to-noise ratio, an excitation coil is necessary in order to create a sufficiently large magnetic field. This generally requires a large excitation current or an increased number of coil turns over a certain length, resulting in a larger sensor. (3) It is vulnerable to external magnetic field interference, leading to reduced measurement accuracy. Fiber-optic sensing technology [4; 12; 21; 22; 23; 24] is based on the response of light phase shifts to changes in the physical field, indicating the properties of the measured object. When the external environment changes, the frequency, polarization direction, and initial phase of the incident light are affected. By detecting and demodulating the returning light signal, the corresponding physical quantities can be determined. The advantages and disadvantages of fiber-optic sensing technology can be summarized as follows:Advantages: Optical fiber Bragg sensors utilize light rather than electricity to carry sensitive information, and optical fibers instead of wires to transmit sensitive data. This provides many advantages over electrical sensors, such as immunity to electromagnetic fields and environmental variations, high accuracy, excellent sensitivity, compact size, good insulation, and the potential for long-term real-time online distributed measurements when integrated with optical fiber communication technology. Disadvantages: Packaging the optical fiber Bragg sensor element requires gluing the fragile optical fiber sensor element or connecting it to other elastomeric components. The elastic modulus of the adhesive layer usually differs greatly from that of the bare optical fiber, and the elastic moduli of the elastomeric elements are not perfectly uniform. This causes errors between the strain measured by the optical fiber and the actual strain of the structure being tested, affecting the reliability. Moreover, the non-ideal shape of the fiber core causes linear birefringence in the optical fiber, leading to errors in the output signal. Temperature fluctuations, mechanical stress, or vibrations can also significantly affect the linear birefringence.