2-Pass Tunnel Installations

Source: Hobas Pipe
Although the majority of Hobas pipes are installed by common open cut construction
Although the majority of Hobas pipes are installed by common open cut construction, these smooth wall, high strength pipes have earned their superior reputation and notoriety primarily due to their success in trenchless applications such as 2-pass tunnels.

Hobas CCFRPM pipes provide many benefits to the user and installer. Some are applicable to any installation method and may be termed universal. Others are most significant and valuable specifically on trenchless installations such as carrier pipes in two-pass tunnel construction.

Majority of applications are sanitary sewer interceptors, however, the pipes are also ideal for other services including storm drainage, industrial effluents, culverts, potable water, sea water, sewer force mains and other corrosive environments.


  • Generically, Hobas pipes are a centrifugal-cast, fiberglass-reinforced, polymer mortar (CCFRPM) construction.
  • Scope
*Diameters: 12" to 102" currently available.

*Standard classes:

Stiffness: Typically between 36 and 72 psi is appropriate, although other values are available and are sometimes needed depending on conditions and joint configuration.

Pressure: Most applications are non-pressure, however, ratings for 50, 100, 150, 200 and 250 psi or in-between classes are available.

*Section lengths: 20 ft. is standard, but 10, 6.5 and 5 ft. sections are sometimes used in curves or when small pits are desired.

*Joints: Several gasket-sealed, bell-spigot configurations are suitable based on installation method and service pressure:

Non-pressure: Flush joint is the easiest to insert and block, although the FWC coupling and the low profile bell-spigot joints have also been used successfully.

Pressure: FWC coupling (frequently with overwrap).

*Fittings: Although not used frequently in tunnel construction, a wide variety of mitered and molded fittings are available including:

  • Elbows
  • Tee base manholes
  • Tees
  • Wyes
  • Reducers
  • Laterals
  • Nozzles
  • Flanges
*Bushings: PVC or stainless steel bushings (typically for 2" pipe connections) are available for grouting or other operations.

Hobas Pipe, 1413 E. Richey Rd., Houston, TX 77073. Tel: 281-821-2200; Fax: 281-821-7715.