Glossary.
An independently driven cutting wheel in the centre of the main - cutting wheel. Independent rotational speed and direction of rotation of the active center cutter. Prevents the blockage of the cutting wheel through increased speed of the center tools.
Mixing arm with drive unit installed in the bottom section of the shield in front of the suction pipe. Used to agitate the bentonite suspension containing excavated material. The agitator avoids sedimentation and clogging of cohesive ground (e.g. clay) in the bottom section of the shield in front of the grip and the suction pipe.
Cavity between pipeline and the surrounding earth which occurs because of the slight intersect of the cutter head to the pipeline.
Automatic tunnelling machine with soil displacement. With this technology, the soil is not excavated but displaced into the surrounding earth.
Automatic tunnelling machine with slurry material removal, also called slurry shield. The excavated material is transferred into a closed slurry circuit in the excavation chamber. On the surface, the excavated material is then separated from the slurry water (separation).
Enhanced AVN technology with additional safety for difficult geologies and larger diameters. Control of the support pressure via an adjustable compressed air cushion. It is often also called mixshield or hydro shield.
Automatic tunnelling machine with pneumatic conveyance. The excavated material is conveyed into corresponding suction cars, operating in the same principle as a vacuum cleaner.
Support of the TBM supply and the muck transport system; it also serves as extension of the tunnel lines.
Tool mounting allowing a change of cutting tools (disk cutters, soft ground tools) from a safe position in the rear.
A highly expansive clay excavated from natural deposits. In Mixshield technology, it is mainly used in the form of bentonite suspension; the transport medium for the excavated material in the slurry circuit, as a support medium (thixotropic liquid) for the tunnel face.
The Berlin construction method describes the star-shaped arrangement of house connections around a collector.
Geological obstacles (mostly individual large pieces of rock encountered in sandy or clayey soils).
Compressed air that has been filtered to be suitable for breathing. Required in man locks and for pressurizing maintenance personnel in the excavation chamber for maintenance works.
Excavation tool in the form of a bucket tooth for partial face excavation.
The bypass is a part of the feed and slurry circuit. By switching the bypass, the feed line is connected to the slurry line so that the flow in the slurry circuit can be maintained when the TBM is stopped without flushing the tunnel face. Thus, the number of repeated starting procedures for the slurry pumps is considerably reduced.
The center part of a shield. Used as thrust cylinder support.
Crush Lining Machine. The machine is deployed for the reconstruction of existing pipelines or the extension of existing pipeline diameters. During pipe jacking, the pilot head guides the pipeline alongside the original route. The cutter head removes the old pipeline material (crush lining procedure).
TBM, equiped with a pressure bulkhead behind the excavation chamber. An over-pressure can be created in the excavation chamber, if needed, in order to compensate the existing earth pressure and/or (ground) water pressure. Among others AVN, AVND and EPB belong to the group of closed tunnelling machines.
Truck trailer for mobile HDD equipment. The functions of mixing, pumping and recycling are rapidly ready for operation on the construction site.
Installation for the transfer of persons and/or material inside and outside the atmospheric area of the tunnel into the pressurized area. Enables access to the tunnel face for the exchange of tools or removal of obstacles. In general, it is built into the front part of the TBM.
Grounds rarely have all characteristics required for the use as support medium in EPB-shield (EPB) operation mode and must therefore be conditioned. During the conditioning process, the natural ground is therefore conditioned to act as a plastic support medium. Depending on the particular geology, conditioning is possible by adding water, bentonite, polymer or foam.
Cone-shaped part of a TBM which is located behind the cutterhead, which is able to crush larger stones for removal due to its special form and rotation.
Work station of the machine operator. Either aboveground in the control container (if remote controlled) or directly inside the machine.
Tool support of hard rock machines equipped with disk cutters for full-face excavation. For small diameters, disk-type cutterheads with muck buckets are sometimes employed and the cutter change is carried out from the front (frontloading). For middle to large diameters, drum-type cutterheads incorporating muck channels are normally used. This cutterhead type is equipped with backloading disk cutters.
Rotating head of the TBM which is equipped with excavation tools. The basic construction and the type and number of tools depend on the project-specific requirements. In general, we distinguish standard, mix ground and (hard) rock cutterheads.
Disk-shaped or spoke-type tool carrier for a full face cutting machine mainly equipped with soft ground tools, used to excavate heterogeneous grounds.
The Herrenknecht method allows the trenchless jacking of a prefab pipe or pipeline in one step with concurrent excavation of the drill hole. The excavation of the soil is carried out with a microtunnelling machine. The pipeline is pushed forward by the Pipe Thruster; transmitting the thrust force, required for drilling, to the cutterhead.
Disks or disk cutters are rotating tools equipped with hardened cutter rings for hard rock tunnelling. During the advance of the machine, the disks are pushed against the rock and break off chips of rock.
Active target unit with a built-in dual axis inclinometer; reacts to a received laser beam and delivers the following values every 0.5 seconds:
- the current horizontal and vertical record of the laser point in relation to the zero point of the ELS (middle of the target);
- the roll angle, the inclination angle and the yaw angle (deflection angle relative to the laser beam);
ELS is permanently installed in the TBM and the current location and height, as well as the tendencies of the TBM are recorded; ELS facilities data communication to the control PC.
The Earth Pressure Balance shield uses the material excavated by the cutting wheel as support medium and does not require secondary support media such as compressed air or suspension. However, conditioning of the ground is generally required.
Excavation tool in the form of an excavator bucket for partial face excavation.
Excavation tools loosen and crush the soil to be excavated at the tunnel face. They are fixed to the cutter head. Type and number of the tools being used depend on the geology to be excavated. Generally, a distinction is made between scraper tools and cutter disks.
Universal excavation tool for partial face excavation. Depending on the condition of the soil, it can be equipped with an excavation shovel, a bucket tooth or a hydraulic hammer.
Exchange of the excavation tools via the access to the tunnel face (long distance tunnelling, compressed air lock).
The external diameter of a microtunnelling machine can be upsized by attaching the additional so-called extension kit; i.e. in general the microtunnelling machine can be used for jacking of pipes both of the respective standard diameter and of the next larger diameter.
Front part of a shield. Used as support for the main drive.
Open or closed TBM which excavates the material on the whole tunnel face with the help of a rotating cutter head.
The natural heat of the earth which can be exploited by means of drilling and which can be used to generate electric power or for power-heat coupling.
System allowing the position of the TBM to be determined. Depending on the diameter, either systems with a gyrocompass (interval measurement) or with laser technology (permanent measurement) are employed.
Horizontal Directional Drilling is a multistage, horizontal drilling procedure in trenchless pipeline construction. With the help of HDD rigs, mainly gas and oil pipelines are installed in the soil.
Specially formed excavation tool on a longitudinal cutting head.
Excavation tool in the form of a hydraulically operated hammer for partial face excavation.
Single-leaf shaft construction method using transferable formwork to complete the final construction of the shaft during the shaft sinking process. The transferable formwork is filled with concrete in-situ (in place on the construction site) and once the concrete has hardened it forms the finished shaft construction and often incorporates steel reinforcement. The concrete hardening process means parallel shaft construction is restricted.
Determines the current roll angle of the laser station and transfers this data via the control unit to the computer of the plc system.
Intermediate jacking stations are needed for long distance pipe jacking. Cylindrical steel cans with integrated hydraulic cylinders are built into the pipeline at defined distances and put into operation when the permissible jacking force is reached at the main jacking station.
Normally a standardised, prefabricated pipe with a smooth, plain exterior contour which is jacked into the underground.
The start of the excavation work of a tunnel and the assembly of the tunnel boring machine. The construction site assembly of the TBM usually takes place on a shield cradle, where the machine is in the start position.
Production facility for the manufacturing of the precast concrete segmental linings. Usually positioned close to the production site in order to shorten the transport distances and to ensure smooth supply of the segments.
Long distance tunnelling is mainly characterised by the employment of intermediate jacking stations and the possibility of the exchange of tools. In this respect, the pipe lubrication has an important function.
Longitudinal excavation tool of a roadheader.
The cutting wheel drive; usually ring-shaped, free centre drive for the cutting wheel and/or the cutterhead of the tunnel boring machine. A large, ring-shaped bearing with internal teeth equipped with numerous pinions on the periphery, which are driven hydraulically or electrically via planetary gears. The free centre makes this drive ideal for Mixshield technology.
A jacking system, installed in the launch shaft which is often called jacking frame (pipe jacking).
Air lock to allow acces to the excavation chamber under compressed air for cutting wheel inspection, cutter change and removal of obstacles. The man lock consists of two chambers (front chamber/main chamber).
A material lock is provided on the TBM to allow tools and other materials to be passed into the pressurized chamber at the front of the TBM. In order to make the handling of heavy objects easier, the transfer lock is equipped with transport trolleys which travel on rails.
Machines with partial face excavation.
Micromachines are manned or remote-controlled TBMs for the construction of tunnels with a nominal width of up to 4.2 m.
Technology for conveying of the extracted material with the help of muck pumps (piston pumps). It is comparable to the concrete pump technology and is employed with EPB machines.
Piston pumps for viscous slurries, plastic materials such as grout, bentonite, conditioned excavated material, etc. Can also pump solid particles up to a certain size. Suitable for high slurry pressures.
TBM without pressure bulkhead behind the excavation chamber. Open shields are normally only employed above groundwater level. Open TBMs include, among other machines, TBMs and partial face excavation machines.
Distance between the upper edge of the pipeline and the surface of the ground and/or the bottom of a body of water located above the pipeline. Often also called cover or overlay.
The remaining ring-shaped gap between the excavation tunnel and the exterior diameter of the shield.
With this excavation procedure the tunnel face is excavated part by part.
Open TBM with excavator or roadheader.
Tunnelling construction method for the creation of underpasses. The pipe arch consists of several pipes, which serve as support structure. This method is employed to construct tunnels with large diameters and short lengths, such as pedestrian subways.
Tunnelling construction method for the creation of pipelines, consisting of individual product or sleeve pipes. With the help of the main jacking station in the launch shaft and, if needed, using intermediate jacking stations, the TBM and the pipeline behind it are advanced up to the reception shaft.
Procedure employed to reduce the skin friction between pipeline and surrounding earth, as well as to support the annulus by means of injected bentonite suspension.
The Pipe Thruster is an additional equipment for horizontal directional drill rigs. It considerably expands the range of application of HDD technology, in particular, with regard to very long crossings and large diameters. The Pipe Thruster is mounted in the launch shaft. While the HDD rig pulls the string of pipes back to the starting point, the Pipe Thruster applies extra force from the other side by pushing the pipeline, which allows for better load distribution on the pipe.
Jacking pipes are lowered separately into the launch shaft and after being jacked with the help of the main jacking station, they form the pipeline.
Structure in the form of a shaft or a pit where the tunnelling ends, designated for the recovery of the tunnelling machine.
Longitudinal cutterhead mounted on a special boom for partial face excavation.
Sealed connection between a stationary and a rotating component. Usually used for a number of fluids such as hydraulic oil for various components, bentonite suspension or foam. The largest rotary coupling on a tunnel boring machine is located in the transition area to the rotating cutting wheel.
Scraper tools are special excavation tools with a blade which is equipped with hard metal parts. They are attached with screws and can be replaced from the rear. Scraper tools are used in mixed soils.
Production hall for the manufacture of the precast concrete segmental lining. Usually close to the construction site in order to shorten the transport distances and to ensure smooth supply of the segments.
Lining rings are made up of a number of segments which are assembled together to form a complete ring in the tailskin of the TBM. The segments are usually made of precast concrete and transported to the place where they will be positioned
Use of settlement tanks or separation plants where the excavation material can settle. The slurry water is collected and returned to the slurry circuit (AVN).
The separation plant is used for the separation of solids and liquids in order to prepare a transport medium which is fed back into the slurry circuit and in order to prepare the extracted solids for disposal. The separation of the solid particles of excavated material from the transport medium takes place in a separation plant in stages which correspond to the grain size of the excavated material being handled. It is based on artificially created centrifugal forces.
Sinking of the ground surface due to loosening and disturbance of the natural layering around the void (stress redistribution).
Single-leaf shaft construction method precast concrete segments to complete the watertight final construction of the shaft during the shaft sinking process. The water tightness of the excavation shaft, the quality of the segments and the time required for construction with precast segments are basis for the required shaft construction.
Cylinder shaped steel construction. Within the protection of the shield segment lining takes place. Consists of a front shield, center shield and tailskin.
In the excavation chamber, the excavated ground is mixed with bentonite suspension which serves as transport medium in the hydraulic slurry system. Slurry pumps (centrifugal pumps) transport the suspension via the slurry line to the separation plant. The separated bentonite suspension is fed back into the circuit via the feed line.
Special cutting tools equipped with a hard metal disks. The soft ground tools are tightened to the support and can be changed from the rear. Soft ground tools are used in heterogeneous ground.
This term describes the treatment of soils with additives, such as bentonite, tensides and polymers for the systematic modification of properties, such as consistency. It is used in tunnelling, in particular with the EPB technology.
Seismic Softground Probing: System for the early detection of boulders. The system visualizes density contrasts and allows the TBM operator to identify boulders up to 40 meters ahead of the cutting wheel, e.g. in sandy or clayey soils.
Crusher for blocks and boulders installed in front of the grid and the suction pipe of hydroshield slurry lines to avoid blockages of the slurry lines.
Sinking of the ground surface due to loosening and disturbance of the natural layering around the void (stress redistribution).
Creation of an over-pressure in the excavation chamber in order to compensate for the existing earth and/or (ground) water pressure.
Mixture of substances consisting of a liquid and the fine particles of solid substances suspended in it. Serves as support medium and/or slurry water for mechanized tunnelling.
Back part of a shield. Within the protection of the tailskin, the segment ring is installed.
The tailskin seal is positioned at the rear edge of the tailskin and seals the annular gap between the inside of the tailskin and the outside of the segmental lining.
The electronic target is used to control the position of the tunnel boring machine. It uses sensors to measure its position relative to the laser beam and passes values to the computer in the control panel. This enables the exact position of the machine to be checked at all times.
Exchange of the excavation tools requiring access to the tunnel face (sometimes via an access to the compressed air lock).
Trailer which can be attached to a tow vehicle and is thus mobile on the road. Serves as rig for HDD equipment.
Circular ring area at the front of the jacking pipe.
Description of the geology of the planned tunnel route, classified by parameters and properties on the basis of geological expert opinions. The geological profile is, together with the existing hydrology (e.g. groundwater level), the basis for the selection of the machine type and the technology.
Manned or remotely controlled TBM to produce tunnel constructions with a nominal diameter of up to 4.2m.
Distance between the upper edge of the pipeline and the surface of the ground and/or the bottom of a body of water located above the pipeline. Often also called overlay.
Compressed air supplied for the operation of pneumatic machines such as tools, winches, cranes and pumps.
