<p>The dynamic analysis of hydraulic fracture propagation is crucial for optimizing hydraulic fracture designs. This study proposes a strain field decoupling algorithm based on the shear strain transfer mechanism, overcoming the challenges in crack opening displacement (COD) calculation under the interference of multiple hydraulic fractures. Additionally, leveraging the advantages of distributed fiber optic sensing technology, a method for monitoring the initiation and propagation of fractures in indoor multi-layered rock masses under true triaxial compression has been established. By analyzing the strain evolution curve, it was verified that the validity of the crack induced strain expression fitted to the strain distribution. The results demonstrate that the proposed method can promptly identify fracture points along the bedding planes. By calculations, the positions and COD of these fracture points at different time can be accurately determined. The predicted fracture morphologies show good agreement with the actual observed fracture shapes. Moreover, the strain response of the fractured thin plate is significantly higher than that of the unbroken thick plate sample.</p>