Surface and subsurface engineering geological mapping for empirical designs of excavation method and support system of Tunnel 6 of Jakarta-Bandung high speed railway, Indonesia

Empirical design of support system at the Tunnel 6 Jakarta – Bandung high-speed railway was based on Basic Quality (BQ) system, which had not been adopted in Indonesia. This research carried out to better understand rock mass quality tunnel construction site by comparing determined BQ that two more popular classifications, namely Geological Strength Index (GSI) and Rock Mass Rating (RMR). Surface subsurface engineering geological mapping were excavation method proposed. The model BQ, GSI, RMR systems showed sedimentary masses Miocene Jatiluhur Formation generally poor very quality, while those Quaternary Volcanic good quality. Based RMR, stand-up time values predicted be relatively low as compared with Formation, implying requirement a quick installation after excavation. In general, combination systematic bolt, shotcrete steel ribs is recommended for this tunnel.