THE ROLE OF MECHANIZED SHAFT SINKING WITH VSM IN INNER-CITY APPLICATIONS-Paper

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The Vertical Shaft Sinking Machine (VSM) is a remotely operated system for constructing deep shafts in difficult ground and high-groundwater conditions, particularly in dense urban areas. Since its first deployment in 2006, more than 111 projects have used VSM, with shafts reaching depths of 115 metres and inner diameters of 4.5–12 metres.<br /><br />The machine excavates with a cutting drum while a surface lowering system controls the shaft’s descent. Excavated material is pumped to a surface separation plant. The shaft remains filled with water to balance groundwater pressure, avoiding groundwater lowering and reducing the risk of settlement and damage to nearby structures. Shaft lining—usually precast concrete segments, but sometimes cast-in-place concrete—is installed at the surface as excavation proceeds. The process is unmanned within the shaft until it is complete and secured.<br /><br />VSM’s key advantages include improved worker safety, accurate shaft construction, reduced site footprint, and flexible equipment layouts. Simultaneous excavation and lining can shorten construction schedules, while the permanent lining may eliminate secondary lining and reduce excavation and concrete use. Electrically powered equipment can also lower noise and emissions, particularly when connected to the local grid.<br /><br />Urban project examples demonstrate the technology’s adaptability. In Paris, VSM constructed ventilation and emergency shafts for the Grand Paris Express in variable clay and limestone, including shafts up to 48 metres deep. In Naples, its compact setup enabled work in narrow historic-city streets, with reported production of nearly five metres per day. In Barcelona, VSM shafts crossed ground ranging from loose sand and gravel to very hard rock, while addressing settlement risks near buildings and existing infrastructure.<br /><br />The paper concludes that VSM can provide a safe, economical, and environmentally preferable alternative to conventional shaft sinking where groundwater, ground conditions, depth, or limited urban space make traditional methods challenging. Its potential applications extend to future underground storage, energy, and urban logistics infrastructure.

Keywords

Vertical Shaft Sinking Machine

VSM

deep shaft construction

groundwater pressure

urban tunneling

remote operation

precast concrete segments

shaft excavation

settlement risk

underground infrastructure