Page 483 - Trenchless Technology Piping Installation and Inspection

Glossary of Terms 433

Sliplining: (1) General term used to describe methods of lining with
continuous pipes and lining with discrete pipes. (2) Insertion of a new
pipe by pulling or pushing it into the existing pipe and grouting the
annular space. The pipe used may be continuous or a string of discrete
pipes. The latter is also referred to as segmental sliplining.
Slurry: A fluid, mainly water mixed with bentonite and sometimes
polymers, used in a closed loop system for the removal of spoil and
for the balance of groundwater pressure during tunneling and micro-
tunneling operations.
Slurry chamber: Located behind the cutting head of a slurry micro-
tunneling machine. Excavated material is mixed with slurry in the
chamber for transport to the surface.

Slurry line: A series of hoses or pipes that transport tunnel muck and
slurry from the face of a slurry microtunneling machine to the ground
surface for separation.
Slurry separation: A process where excavated material is separated from
the circulation slurry.
Slurry shield method: Method using a mechanical tunneling shield with
closed face, which employs hydraulic means for removing the excavated
material and balances the ground water pressure. See also earth pressure
balance machine.
Social costs: Costs incurred by society as a result of underground
pipeline construction and renewal. These include but not limited to traffic
disruptions, environmental damages, safety hazards, inconvenience to
general public, and business losses owing to road closures.
Soft lining: See cured-in-place pipe (CIPP).

Spiral lining: A technique in which a ribbed plastic strip is spirally
wound by a winding machine to form a liner, which is inserted into a
defective pipeline. The annular space may be grouted or the spiral
liner expanded to reduce the annulus and form a close-fit liner. In
larger diameters, the strips are sometimes formed into panels and
installed by hand. Grouting the annular space after installation is
recommended.
Spiral weld pipe (casing): Pipe made from coils of steel plate by
wrapping around a mandrail in such a manner that the welds are a
spiral helix.
Spiral wound: In this process a new pipe is installed inside the existing
pipe from the continuous strip of polyvinyl chloride (PVC). The strip has
tongue and groove casting on its edges. It is fed to a special winding
machine placed in a manhole, which creates a continuous helically wound
liner that proceeds through the existing pipe. The continuous spiral joint
is watertight. Upon completions of the annulus space between the lining
and the existing pipe wall is usually required.