Operating principle at a glance:
The modular design of the VSM technology enables flexible construction site set-up, especially for inner-city applications.
Areas of application for the Vertical Shaft Sinking Machine (VSM)
The Vertical Shaft Sinking Machine (VSM) from Herrenknecht enables the reliable and efficient construction of vertical shafts – even in complex ground conditions with high groundwater levels. The system impresses with its flexible and compact jobsite setup, which makes it particularly effective in inner-city areas and confined spaces. With diameters of 4.5 to 18 meters and depths of up to 250 meters, the shafts are used in a variety of ways: as launch and target shafts for tunnel drives, as access and ventilation shafts for traffic tunnels or as service and entry points for underground structures. Deep shafts are also suitable for underground storage facilities or automated parking solutions, such as U-Park systems.
The shaft is constructed on the surface parallel to the soil excavation, as shown here with concrete segments in Barcelona, or alternatively by using in-situ concrete.
VSM equipment: compact and flexible
In addition to the two main components, the actual shaft boring machine and the lowering unit, the VSM jobsite equipment also includes the separation plant, the control container and supply units. The equipment is completely modular, so it can be arranged flexibly depending on the available space. This advantage is particularly evident in inner-city projects. For example, the separation plant can be set up in a side street if there is not enough space at the shaft.
Excavation and shaft construction in one step
Before the cutting work begins, the shaft boring machine is inserted into the launch structure and fixed in place. The lower concrete ring, the so-called shaft cutting edge, cuts into the ground. The swiveling and extendable roadheader boom enables the step-by-step, complete excavation of the shaft cross section with overcut below the shaft cutting edge. A rotating cutting drum with round shank bits crushes the soil at the shaft bottom. The muck is hydraulically pumped to the surface via a water circuit to the separation plant.
Several lowering units are installed firmly on the concrete ring foundation at the surface and connected to the shaft cutting edge by steel cables. This allows the entire shaft structure to be held and lowered in a controlled manner. The overcut and the bentonite lubrication reduce the friction between the shaft and the ground. Ring building takes place on the surface in parallel with the soil excavation. The simultaneous operations (excavation, muck removal, shaft lining, and sinking) enable sinking rates of up to 5 meters per shift with VSM technology.
Functional principle
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Under water to the finished shaft
At the start of the cutting work, the shaft is flooded with water, creating a water circuit for muck removal and eliminating the need for groundwater lowering. The separation plant separates the material from the water, which is pumped back. Once the target depth has been reached, the machine is recovered, the shaft is sealed with underwater concrete and the annular space is filled with grout. After the water is pumped out, the shaft is ready for further use.
A cutting drum equipped with excavation tools loosens the soil on the shaft bottom
Hydraulic conveying of the muck to the surface by means of a submersible motor pump
Precise lowering of the shaft structure via the lowering units
Shaft construction on the surface with precast reinforced concrete segments or in-situ concrete
Everything in view from above
All operations are controlled and monitored from the surface. All operational data is collected, displayed and documented in the control container so that the machine operator has an overview at all times and can react accordingly.
The flexible arrangement of the VSM equipment makes shaft construction possible even in narrow streets, as here in Girona.
Future-proof shaft construction for growing requirements
The global trend toward underground infrastructure in urban areas necessitates the construction of increasingly deep shafts. In difficult ground with high groundwater levels, conventional methods are reaching their technical and economic limits. Mechanized shaft construction using VSM technology offers clear advantages in terms of budget, construction time, and occupational safety.
Still got questions?
We are ready!
Steffen Dubé
President and General Manager Herrenknecht Tunnelling Systems USA Inc.
Gerhard Goisser
Commercial Manager Herrenknecht Tunnelling Systems USA, Inc.