The field test of pipe bursting and replacement system by the EXPANDIT, and the ground movements

Underground sewer pipes which were in place for over 60 years are mostly deteriorated and need costly maintenance and repair in a lot of cities of Japan. The Expandit Pipe Bursting System was acquired in 2004 from England. The bursting process is able to replace the existing pipeline with same or larger diameter. It advances from the insertion shaft to the reception shaft in sequences, which are repeated until the full length of the original pipe is replaced. In each sequence, one segment of the pipe is burst in the steps; first the bursting head is pulled into the old pipe for the length of the segment, then the head expanded laterally to break the pipe. The jacking pipes for sewers which were made at the pipe factories should be used for the new pipes. The old pipes are burst at the radial direction and a space for the new pipe is provided. The rear of the bursting head is connected to the replacement pipe and also hydraulic supply lines are inserted through the replacement pipes. This system can be applied in the pipe inner diameter of 200-600mm, and make the flow capacity of the repaired sewer increase, even in the case of displacing of the pipe joint and deforming the vinyl chloride pipe. Poly vinyl chloride pipe which has less vertical diameter compared with the horizontal diameter can be easily burst and replaced by the new pipe. The joint unfitting pipe and bended pipe at the pipe-joint can be burst and the new pipes can be installed along the smooth connection line. This paper describes the results of the field test of pipe replacing operation at the various irregular conditions of the old pipes and the results of measurements and analyses of the ground movements.