Tunnel Boring Machine (TBM) is generally used to excavate tunnels with circular cross section through variety
of soil and rock strata continuously. Disc is the most commonly used as cutter in TBM today. There are several
factors that affect the performance of the disc cutter to work optimally, such as spacing between the discs. This
study aims to determine the excavation capability of concrete by discs cutter with finite element method in RS3
software. Numerical simulations were carried out by varying five spacings between the discs, namely 12 mm, 17
mm, 28 mm, 30 mm, and 33 mm. The parameters obtained from the model are strength factor depth (SF=1) as the
depth of penetration and the value of minimum principal stress (????3) as a proof of failure zone. The penetration
depth of 12; 17; 28; 30; and 33 mm is 2.85; 2.98; 3.89; 4.16; and 4.33 mm. The 33 mm spacing which has
spacing/penetration ratio 7.62 is the most optimal ratio due to its lowest specific energy, that is 18,51 MJ/m3.