How does a shaft boring machine work? A shaft boring machine (SBM) is a heavy-duty engineering machine designed specifically for vertical or near-vertical shaft construction. It integrates tunneling, support, mucking, and shaft wall assembly. Compared to traditional blasting methods, it offers advantages such as high mechanization, safer construction, and improved efficiency. It is suitable for applications in mines, pumped-storage power plants, urban underground spaces (such as smart garages and subway ventilation shafts), and military engineering.

   Here’s an explanation of its working principle:

   1. Positioning and Setup

   The machine is installed at the surface directly over the planned shaft location.

   A guide system is established to keep the machine centered and aligned during the boring process.

   The shaft collar (the initial few meters) is usually pre-excavated and reinforced with concrete to stabilize the upper section.

   2. Cutting/Excavation Process

   The SBM is equipped with a large rotary cutting head fitted with disc cutters, roller cutters, or pick tools.

   The cutting head rotates and gradually breaks the rock or soil at the shaft bottom.

   The cutting action is similar to a tunnel boring machine (TBM), but vertical instead of horizontal.

   3. Muck Removal (Material Handling)

   The broken rock (muck) is removed continuously or batch-wise:

   Suction system or pneumatic conveying: Material is vacuumed upward through a pipe.

   Bucket hoisting or skips: Excavated material is collected and hoisted to the surface.

   Efficient muck removal ensures uninterrupted cutting.

   4. Machine Support and Guidance

   The machine is usually suspended by ropes or supported on a stage platform that gradually lowers as the shaft deepens.

   Hydraulic cylinders or winches maintain vertical alignment and control the downward advance.

   5. Shaft Lining

   To stabilize the freshly excavated shaft, concrete lining segments or shotcrete are applied directly behind the cutting zone.

   The SBM often integrates lining installation with excavation to minimize risks of collapse and groundwater inflow.

   6. Advance Cycle

   Cutterhead rotates and grinds rock at the shaft bottom.

   Muck is continuously removed.

   Machine gradually lowers under controlled conditions.

   Shaft lining is installed concurrently or shortly after excavation.

   This cycle repeats until the desired shaft depth is reached.

   A shaft boring machine works by mechanically cutting rock at the shaft bottom with a rotating cutterhead, removing the muck to the surface, and simultaneously installing shaft lining as the machine progresses downward.