In pipe jacking operations, the cessation of jacking can lead to a rapid buildup of resistance in certain soils. Even brief stoppages of several hours can necessitate a significant increase in jacking force, sometimes ranging from 20% to 40%, to resume the process. This highlights the importance of continuous pipe jacking operations to minimize resistance and ensure smooth progress.
For long pipelines, frictional forces between the jacking pipes and the surrounding soil can be substantial. In some cases, these forces may become so high that the jacks in the jacking pits struggle to overcome them. Even if the jacks can generate enough force, the high loads experienced by the jacking pipes during driving can stress the pipe material, such as concrete, to the point of failure. Therefore, pipe strength becomes a critical factor in determining the need for intermediate jacking stations.
Intermediate jacking stations are strategically placed along the pipeline route to provide additional pushing force. By distributing the jacking force over multiple points, these stations reduce the load on individual pipe sections, mitigating the risk of damage or collapse. They also help to maintain a more consistent jacking force, ensuring a smoother and more controlled installation process.
In conclusion, the decision to use intermediate jacking stations in pipe jacking projects depends on various factors, including soil conditions, pipeline length, and pipe material strength. By carefully evaluating these factors, engineers can optimize the jacking process, minimize the risk of pipe failure, and ensure the successful completion of the project.