A comprehensive advanced engineering geology investigation is essential for the construction of a tunnel. During the construction stage, tunnel face mapping is strongly suggested to observe and identify geological conditions that have not been recorded directly by the borehole data. Tunnel face mapping is conducted to identify changes or variations in geological engineering conditions prior to excavation. The Budong-Budong Dam diversion tunnel was excavated using an excavation method and a selection support system based on the Rock Mass Rating (RMR) classification determined in the design stage. However, the geology of tunnel construction poses unique challenges, primarily as it is located in volcanic rock and steep slope topography with a high potential for landslides and rock failures. This research aims to provide an evaluation of the tunnel excavation method and support system based on tunnel face mapping in the inlet side of tunnel. The two empirical methods used are Rock Mass Rating (RMR) and Q-System classifications. The results show that the inlet tunnel consists of tuffaceous sandstone and tuffaceous siltstone. According to RMR, the rock mass quality along the inlet tunnel side consists of a fair rock mass class with RMR values ranging from 42 to 53. According to Q-System, the inlet side of the tunnel is dominated by poor rock mass quality. The tunnel excavation method using top heading and bench excavation with 1.5 - 3 meters advance in heading is recommended based on RMR. The tunnel requires a combination of rock bolts and shotcrete represents the optimal support system for the inlet tunneling area. In order to mitigate risk and ensure the safety of the tunnel, it is recommended a numerical analysis to verify the empirical design.
Level
Internasional
Status
Dokumen Karya
No
Judul
Tipe Dokumen
Aksi
1
Permatasari et al 2025 IOP_EES_1486 Tunnel face mapping for evaluate Budong.pdf
