Pipe Jacking & Culvert Jacking

Pipe Jacking is a specialist technique used to install underground pipelines and culverts with minimal disruption to property, traffic or services on the ground surface. Pipes and culverts are progressively advanced through the ground using high performance hydraulic jacks. Material at the head of the pipeline or culvert is excavated to the exact profile of the structure prior to jacking. This material is removed from the jacking pit via the structure being jacked where it is hoisted and stock piled adjacent to the jacking pit. Pipejacking is used for sewers and stormwaters, gas and water mains, electricity and telephone cables, box culverts and subways

                                                         

                                                         

                                                         

                                                         

Concrete pipejacking methods use a steel shield with hydraulic jacks that are positioned at the front of the pipeline. In unstable ground conditions the jacked structure may be installed as a sleeve through which the actual service will later pass or within which an in-situ invert may be constructed. A single sleeve pipe may be used to install a variety of smaller services. Concrete pipes and culverts are readily available in a diameter ranging from 900mm to 3 000mm. Unit lengths may be varied to suit individual contract design and construction parameters. Working from both ends of the pipeline distances of 300m and more may be jacked by the use of intermediate jacking stations. In addition when high jacking pressures are anticipated, intermediate jacking stations can be installed at predetermined positions within the pipeline to reduce the overall load on the thrust wall and pipe joints. The number and positions of intermediate jacking stations depend on the length of pipeline and the prevailing ground conditions. On completion these intermediate jacks are removed and the pipes closed to form a butt-end joint within a steel sleeve. The use of well pointing techniques in saturated conditions and the use of explosives when rock is encountered means that pipe jacking succeeds as a proven alternative under the most adverse and varying ground conditions.