Underground Engineering Division
Technologies and operations for underground engineering
Horizontal directional drilling from DN 63 to DN 400
Horizontal drilling is a technology suitable for the laying of pipes for underground services (water conduits, gas lines, cable distribution systems and pipe sleeves for various lines) wherever it is necessary to avoid any breakage of existing surfaces, e.g. airport premises, historical city centres, railway lines or factory shop floors.
The horizontal drilling technology has a number of advantages, e.g. it makes work possible in narrow streets between houses, reduces the restraints on traffic during the work to a minimum, has a performance capability of up to 200 meters per day, provides the possibility of making changes in the direction of drilling and avoiding barriers, and is independent of electric power and water supply sources.
The boring machines available to the Division’s employees for horizontal directional drilling are the GRUNDODRILL 15X on the Tatra T 815 a chassis, and the FLOWTEX on the LIAZ chassis.
If you are interested in horizontal directional drilling, contact the site engineer Michal Sodomka at tel.. +420 602 416 429 or Ivo Bánský at tel. +420 602 539 608.
Mechanized and non-mechanized shield driven tunnels
Overview of shields
Overview of shields | Shield driven diameter | Tunnel clearance | The size of the starting shaft |
|---|---|---|---|
Diameter „200“ | 2 024 mm | 1 660 mm | 4,0 x 4,5 m |
Diameter „256“ | 2 588 mm | 2 180 mm | 4,0 x 5,0 m |
Diameter „305“ | 3 082 mm | 2 630 mm | 5,0 x 6,0 m |
Diameter „360“ | 3 640 mm | 3 180 mm | 5,5 x 7,5 m |
Tunnelling is performed from lined starting shafts, the sizes of which are shown in the table specified above. The length of a shield driven section may be up to 150 meters. The walling of a bored tunnel is made of prefabricated reinforced-concrete components. This technology may be used in complicated geological conditions of the rocks classified in workability class 1 to 4 , and even under the subterranean water level.
Traditional drilling
This type of drilling is used particularly under unusual or difficult conditions which require the shape or gradient of the construction to be changed and some breaking, interconnecting or connecting work to be performed. Stopes may be adapted to the conditions of the drilling performed.
Excavation of shafts with lining
Shafts with lining are used for all types of tunnelling processes or for the execution of trenchless pipe laying, as the case may be. Excavation of shafts is also performed separately, e.g. for the construction of pits.
Steel pipe jacking
The Underground Engineering Division performs trenched steel pipe jacking with pipes from DN 800 to DN 2350 and subsequent optional fitting with concrete or plastic pipelines up to the distance of 60 meters. So as the pushing device might be applied, starting shafts or a support system must be constructed and used for making culverts under communications.
Reinforced-concrete tube jacking
The method of DN 1000 and DN 1200 reinforced-concrete tube jacking is used to construct railway and road subways. The advantage of this method is the possibility of partial altitudinal and directional control by means of the so called front-shield. The execution of jacking requires a starting shaft with lining to be constructed, the size of which depends on the type of applied pushing station.