The capacity of rock to be spalled, ripped, chipped, and broken into smaller pieces to allow the advance of the MTBM. Key properties impacting cutability include the frequency of discontinuities, unconfined compressive strength, tensile strength, hardness
See Face AccessAccess to the location where excavation is taking place, typically through the cutting chamber. MTBM configuration may only allow limited personnel access to the back of the cutter wheel from within the pipe string. An airlock may also be required in the rear of the MTBM to maintain air pressure for counterbalancing earth and groundwater pressures..
Any rotating tool or system of tools on a common support thatexcavates at the face of a bore.
Any rotating tool or system of tools on a common support that excavates at the face of a bore. Usually applies to mechanical methods of excavation.
The actual teeth and supporting structure that is attached to the front of the lead auger, drill stem or front face of the tunnel boring machine. It is used to reduce the material that is being drilled or bored to sand or loose dirt so that it can be conveyed out of the hole. Usually applies to mechanical methods of excavation, but may also include fluid jet cutting.