Buderus Manual on Trenchless Installation of Ductile Cast ... - Duktus

Trenchless replacement of gas and water pipelines
3. Trenchless replacement of gas and water pipelines
3 General
There has been tremendous progress in the development of no-dig or trenchless techniques
for installing new pressure pipelines and replacing old ones, particularly when this has to be
done in inner city areas. There is an increasing trend towards the use of these techniques.
Whereas large areas are covered with excavated soil when open-trench techniques are
used, with trenchless techniques any nuisance of this kind is kept within acceptable limits.
The following are some of the major advantages of trenchless techniques:
• The digging-up of roads and earth-moving work are reduced by up to 80% or more
(Fig. 3.1)
• There is less excavated soil and bedding material to be transported (Fig. 3.2)
• Less space is needed for the site equipment and facilities (this is particularly important
in inner city areas, Fig. 3.3)
• Sites can be confined to several small „points“ and it is therefore possible to cover the
pit and put it out of reach of the weather, which benefits the quality of the product,
i.e. the pipeline that is installed.
Fig. 3.1 Space required for open-trench installation Fig. 3.2 Open-trench and trenchless installation:
comparison of volumes of material transported
32
Open-trench
installation
Equipment
Trenchless installation
Volume of material transported
Fig. 3.3
Trenchless installation does not disrupt traffic