Engineering geological mapping for empirical design evaluation of Tunnel 10 of Jakarta - Bandung high-speed railway, Indonesia

An engineering geological mapping was carried out at the construction site of the Tunnel 10 of Jakarta - Bandung High-Speed Railway to obtain data and information of the engineering geological conditions, particularly the rock masses. This research aims to determine the rock mass classes at the tunnel construction site and recommend the tunnel support system based on the Rock Mass Rating (RMR) and the Japan Society of Civil Engineers (JSCE) systems. This research is expected to better understand the rock mass classes, which were previously determined based on the newly applied Basic Quality (BQ) system for the tunnel support empirical design. The results showed that the research area consisted of young volcanic products, namely moderate to highly weathered tuff breccia and andesitic breccia. The uniaxial Compressive Strength (UCS) of rock mass varies between 1-25 MPa. The RMR value ranges from 21 to 40, indicating disintegrated and poor rock mass quality. The proposed tunnel support system is the combination of shotcrete, steel support for top heading and bench support, arch sidewall, and invert concrete.