Delivering leading pipe jacking solutions
Where extremely tough ground conditions may require machine or manual excavation, we offer a pipe jacking solution. Pipe jacking is a trenchless method used for installation of steel pipes and concrete crossings generally used for short and shallow installations under roads, railways, and various complex applications where other methods may cause surface settling or heaving. Bothar built pipe jacking equipment balances earth pressure at the tunnel face for rapid tunnelling with minimal settlement. It is easy to steer and operate to provide a simple solution to complex construction needs.
What is pipe jacking?
Pipe jacking is a trenchless method used to install steel pipes and concrete crossings underground that requires two, relatively small entry and exit pits — typically at manhole locations. A concrete thrust slab is constructed in the shaft for the pipe jack to push against when pushing the pipe through the soil. Coupled with a tunnel boring machine (TBM), the pipe jack uses a hydraulic force to push the TBM through the ground to create a path for the pipe. The TBM has various cutting heads used for different types of geologies including sandy soils to clay and rock. Once the TBM has started excavating, prefabricated pipe is placed into the shaft and pushed along the route until the cutterhead reaches the exit pit.
This method can be used to install pipes with an internal diameter up to 3,500 millimetres of various drive lengths. Unlike microtunnelling and Direct Pipe® installation, pipe jacking is not slurry supported which limits certain uses of this method. The viable route length depends on several factors including the ground geology and the pipe diameter. Hard geologies such as gravel and rock have a greater potential for friction build up which limits the drive length, and a pipe with a small diameter may only be able to be pushed a short distance, whereas a larger pipe can be pushed further. Ground water is another consideration when determining whether this method is feasible. When ground water is present, our team provides an integrated dewatering solution that pumps water through a filter to remove sediment. This requires more equipment and a larger team to operate the site.
Advantages of Bothar pipe jacking
Minimal environmental disruption
There are several environmental benefits of Bothar built pipe jacking solutions. This pipe crossing method requires a smaller operational site compared to other tunnelling solutions because it uses less equipment overall. Typically used for short crossings, this method can use existing manholes as entry and exit points. If this option isn’t available, the space required for shaft construction is minimal. With our earth pressure balance machine, we are able to use the excavated soil as a direct support medium to limit settlement.
Applicable in various types of ground conditions
Our pipe jacking solution can be used in various ground conditions from soft, sandy soils to hard rock. With different cutting heads and our earth pressure balance machine, we are able to complete crossings safely and efficiently where no groundwater is present.
When a simple crossing is needed, our pipe jacking method offers a cost effective solution. This non-slurry supported tunnelling method requires less equipment and a smaller team to complete a crossing. Significant time savings are also realized in soil disposal compared to slurry supported machines. Our team of engineers may recommend pipe jacking for short crossing within a multi-crossing project.