# Improved FraSegNet-Based Rock Nodule Identification Method and Application
## 3 Evaluation Methods
### Rock Mass Parameter Evaluation Metrics  
The FraSegNet algorithm shows better nodal extraction accuracy and robustness after improving the backbone network, adding the attention mechanism, and using the dynamic learning rate strategy. However, to check if the improved algorithm extracts nodal features accurately, using only image segmentation metrics (e.g., IoU and F1-Score) is not enough. Verification should also be performed using actual mechanical criteria. The Barton-Bandis nodal parameter mapping and the Hoek-Brown strength criterion are proposed to validate FraSegNet's accuracy in extracting nodal features, connecting the algorithm's segmentation performance to the mechanical properties of the rock body.  
Correlation Analysis of Nodal Cleavage Parameters Rock Mass Parameters  
Enclosed rock characteristic parameters describe the distribution of structural and geometric features in the rock mass. These parameters are key indicators of the rock's engineering properties. Common surrounding rock characterization parameters include the following: (1) Fracture Density: It is the total length of fractures per unit area, showing the level of fracture development. (2) Fracture Length: It is the linear length of a single fracture, which affects the continuity of the rock mass. (3) Fracture Width: It is the opening width of a fracture, which determines how much the rock mass's stiffness and strength areweakened. (4) Fracture Dip Angle: It is the angle between the fracture and the horizontal plane, which affects the fracture's sliding tendency. (5) Fracture Area: It is the total area of fractures in the two-dimensional projection, showing the distribution range of fractures.  
Commonly used rock mechanics parameters include the following: (1) Density: It describes the mass distribution of the rock mass. (2) Bulk Modulus: It reflects the ability of the rock mass to deform under uniform pressure. (3) Shear Modulus: It describes the ability of the rock mass to resist shear deformation. (4) Elastic Modulus: It is the deformation capacity of the rock mass under axial stress. (5) Cohesion: It reflects the rock mass's resistance to shear failure. (6) Friction Angle: It describes the sliding resistance of the rock mass. (7) Tensile Strength: It is the failure strength of the rock mass under tensile stress. (8) Poisson's Ratio: It is the ratio of lateral deformation to axial deformation in the rock mass.  
Higher fracture densities weaken the rock mass, reducing its cohesion, tensile strength, and elasticity. Fissures lower the strength and stiffness of the rock, increasing the risk of slippage and damage. As fissure width increases, the stiffness of the rock decreases, lowering the modulus of elasticity and shear modulus. Larger fissures allow more space for deformation, making it easier for the rock to deform and be damaged. The inclination angle of the fissures affects the rock's tendency to slip. A larger inclination increases the risk of slippage and reduces the friction angle, affecting stability. Fissures also influence the rock's deformation, especially under axial stress. The distribution, length, and width of the fissures affect the rock's Poisson ratio, impacting its lateral deformation.