A Variety of Trenchless Technologies for Pipeline installation
In pipeline construction, occurring surface and sub-surface obstacles such as waterways, roads and underground installations or environmentally sensitive areas have to be crossed. These obstacles require specialized construction techniques with minimum environmental impact. In the planning stage of a pipeline crossing project, all surrounding conditions have to be analyzed to find the safest and most cost-efficient method to be deployed. Besides technologies made especially for the pipeline industry, e.g. HDD, there is a growing number of alternative pipeline installation methods, which partly come from the tunneling industry. Whereas some of the technologies install the product pipeline directly into the borehole (e.g. HDD, Direct Pipe®, Pipe Express®), others install casings in which the pipeline is pulled-in in a further step, e.g. by a Pipe Thruster. In most cases, pipeline casings are installed using Pipe Jacking and Segment Lining Tunnelling equipment, depending on crossing length, diameter and geology. By using Pipe Jacking equipment, it is also possible to jack steel product pipes through the ground. In this case, welding of the steel pipes has to be carried out during the pipe jacking works. Direct Pipe® combines the well-established Slurry Microtunneling Technology with the Pipe Thruster Technology. It is ideal for pipeline river crossings where HDD is too risky to apply. PipeExpress® is a semi-trenchless installation method with minimum impact on the surface. In comparison to the conventional cut and cover method Pipe Express® only requires approx. 30% of the right of way. Thereby less top soil needs to be romoved, less trees cut and most importantly less precious farmland is being affected by the installation method. This paper presents the alternative trenchless construction methods for pipeline crossings. Several selected case studies prove the wide application field of trenchless techniques for the pipeline industry.