Tunnel boring machine

At the front face tunnel boring machines (TBM) are equipped with a cutter head to cut themselves through ground and rocks. Depending on the requirements due to the existing soil conditions (rocks, silt, soil, etc.) and specifications, TBMs are produced in the most different designs. Some of the differing variables are: diameter of cutter head, cutting tools (type, size, arrangement, etc.), advance rate, type of shield (EPB shield, mixed shield, etc.), evacuation of overburden. Note: EFB shield – earth pressure balance shield