Identification and Stability Analysis of the Key Blocks in Surrounding Rocks of a Tunnel in Lantian Country,Shanxi Province

An innovative method is proposed,aiming at the problems of block identification and stability analysis in jointed tunnels,which integrates discontinuity information acquisition with accurate block identification.Photogrammetry technology is utilized to rapidly collect discontinuity information of surrounding rock.The surface cutting element algorithm is incorporated into the grid-based block identification method,enabling the identification of complex block shapes through cutting and combination techniques.It was systematically outlined that the process of surrounding rock grid modeling,block identification,and stability analysis,aiming to provide readers with a research framework.Taking the Lantian Tunnel project in Shaanxi Province as a case study,key blocks have been successfully identified,and the analysis results are consistent with field investigations.The study reveals that faults and joints govern the stability of tunnels,and the instability of key blocks can trigger a chain reaction,posing a threat to tunnel structural safety.Therefore,it is necessary to identify and reinforce key blocks accurately.