## 2 Methodology
### Calculation Method of Rock Mass Evaluation Indices
drilling depth length, which is related to the degree of rock mass fragmentation and can be obtained from field record logs. It is important to note that \(L\) refers to the drilling depth length rather than the total length of the recovered core. The above calculation process is performed for each drilling depth, and the calculated RQD is then correlated with the drilling number, starting depth, and ending depth, thereby achieving RQD logging for all core images. If the core has not been marked with drilling depth intervals or if field logs are unavailable, Equation (2) can be used to calculate and log the RQD for each single-row core or each core image. \[RQD=\frac{\sum_{i=1}^{m}\left(l_{i}\right)}{L_{c}}\times\eta\times 100\%=\frac{ \sum_{i=1}^{m}\left(n_{i}\right)}{N_{c}}\times\eta\times 100\% \tag{2}\]  
where \(L_{c}\) and \(N_{c}\) represent the length of a single-row core and the corresponding number of pixel points along the centerline, both of which are constant values. \(\eta\) is the core recovery rate, defined as the ratio of the length of the recovered core to the actual drilling depth. The core recovery rate is recorded for each core image. However, since the RQD classification method is a single-factor classification approach, the parameters it considers are limited, and it often fails to fully reflect the overall quality of the rock mass. Therefore, a comprehensive classification method using multiple rock mass indices is required. GSI is not only a comprehensive index method for evaluating rock mass quality but also an essential parameter in the Hoek-Brown criterion [24]. GSI is primarily determined based on the structure of the rock mass and the characteristics of its discontinuities. Information about the rock mass and joints can be obtained through digital photogrammetry of the structural surfaces. Further details of this process are given in Section 4. The structure of the rock mass and the characteristics of the discontinuities are represented by the structure rating (SR) and the surface condition rating (SCR), respectively [25]. SR is related to the joint volume (J\({}_{v}\)), while SCR is influenced by factors such as  
Figure 5: The relationship between loss, accuracy, and epoch step in the identification of core segment longer than 10 cm (contain 10 cm). **(a)** Validation loss; **(b)** prediction accuracy. Figure 6: Intelligent recognition of core RQD. joint roughness (R\({}_{r}\)), weathering (R\({}_{w}\)), and filling (R\({}_{f}\)). The values of these parameters can be found in the relevant literature [26]. The values for SR and SCR can be calculated using the following equations:  
\[SR=-17.5\ln J_{o}+79.8 \tag{3}\]  
\[SCR=R_{r}+R_{w}+R_{f} \tag{4}\]  
It is sometimes difficult to obtain data on the quality of the rock mass and joint information from within the mine. In such cases, the rock mass structure is represented by RQD. The characteristics of the discontinuities are quantified using the joint roughness number (\(J_{r}\)) and the joint alteration number (\(J_{a}\)) [27]; these are determined as follows:  
Figure 3.0  
As a result, we obtained several GSI values from different locations within the study area. Using these data, we performed rock mass quality classification for the mine and provided data support for calculating rock mass strength parameters. Further details of this process are given in Section 2.3.