Static pull systems for pipe bursting do not include the use of pneumatic hammers to effect the bursting process. The bursting is accomplished using the splitting force created by the pulling of the slanted bursting head into the existing pipe. Cables or quick connect rod systems are used to provide the tensile pull. Splitting may be aided by the use of fins on the face of the bursting head to create stress concentrations in the existing pipe.
Assist Techniques
For many pipe bursting applications in suitable pipes and surrounding ground conditions, the bursting process is fast, simple and effective. When the job conditions are more challenging, there are some assist techniques that can be used to facilitate the pipe bursting and pipe pull-in challenges. To aid in pipe fracture, it is possible to create stress concentration by scoring the existing pipe ahead of the bursting process. For large-diameter long distance pipe bursting applications, the friction on the replacement pipe as it is pulled through the ground can slow and even stop the bursting process. Annular space lubrication, as in microtunneling, may be used but it is also possible to add a pipe ramming device to the rear end of the replacement pipe. It is not considered that the ramming device contributes significantly to the impact or force at the bursting head itself but rather that the longitudinal vibration prevents the replacement pipe from being seized in the surrounding ground.