Reinventing Pipeline Installation: The Direct Pipe Revolution
Les méthodes d’installation sans tranchée
Reinventing Pipeline Installation: The Direct Pipe Revolution
If you are looking for a trenchless method to install pipelines in any geology, you might want to consider the Direct Pipe method. This method combines the benefits of microtunneling and horizontal directional drilling (HDD) to achieve a fast, efficient, and cost-effective installation of pipelines with lengths of more than 1,500 meters.
The Direct Pipe method involves simultaneous excavation of the borehole and installation of the pipeline in one step. It does not require back reaming as in HDD, or a shaft for pipe thrusting as in microtunneling. It can handle hard and soft rock, unstable soil, and large boulders, as the pipe is installed along with the borehole excavation, eliminating the need for the borehole wall support.
The main components of the Direct Pipe method are:
- A slurry-supported microtmicro tunnellingunnelling machine (AVN) that is mounted and welded onto the front of the pipeline. The machine excavates the soil using a cutter head that can be equipped with cutting tools depending on the soil conditions. The machine is controlled by an operator on the surface near the rig and monitored by a gyro-based navigation system.
- A slurry circuit installed inside the pipeline allows the excavated material to be transported back to a separation plant on the surface. The plant separates the slurry and soil, and the cleaned slurry is fed back into the lubrication system.
- A pipe thruster that grips the pipeline from the outside and pushes it into the ground in strokes of 5 meters. The pipe thruster provides a thrust force of up to 750 tonnes and transfers it to the cutter head of the microtunnelling machine. The pipe thruster also has a lubrication ring that acts as a transition point between the machine and the pipeline.
- A prefabricated pipeline that is laid out on rollers on the surface and welded to the end of the microtunnelling machine. The pipeline acts as both a tunnel lining and a product pipe. The annular gap between the pipeline and the borehole wall is filled with bentonite to facilitate easy pipe installation.
The advantages of the Direct Pipe method are:
- It is a one-pass method that does not require multiple steps or intermediate operations.
- It can install pipelines with large diameters (up to 60 inches) and long lengths (up to 1.5 km) in one continuous drive.
- It can handle any geology, including mixed ground, water-bearing soil and rock formations.
- It has a minimal footprint on both sides of the crossing, as it does not require deep shafts or large equipment.
- It reduces environmental impact, as it does not generate drill cuttings or require fluid disposal.
The Direct Pipe method was first used in Germany in 2007 and has since been applied in various projects around the world. It is an innovative and versatile trenchless technology that offers a reliable and economic solution for pipeline installation.
The Direct Pipe method represents a significant breakthrough in the field of pipeline installation, offering a fast, efficient, and cost-effective solution for projects of all sizes and in all types of geological conditions. This innovative approach, combining the advantages of microtunneling and horizontal directional drilling, allows for the installation of large-diameter pipelines over impressive distances in a single operation. By eliminating the need for additional boreholes or deep shafts, the Direct Pipe method significantly reduces the environmental footprint while providing great versatility. Since its introduction in Germany in 2007, this method has proven its reliability and adaptability to diverse conditions worldwide. In essence, the Direct Pipe method embodies the future of pipeline installation, transforming this essential industry in a sustainable and efficient manner.