Trouble Shooting for Trenchless Liner Installation During Sewer Line Rehabilitation

Lining is being used by the utility industry as a cost effective solution to rehabilitate utility lines. Many types of liners, such as, cured-in-place-pipe (CIPP), fold and form PVC, deformed & reformed HDPE, etc., are being used to restore structural integrity of deteriorated pipes and to reduce inflow/infiltration. Most of the lining installation is carried out without any problem, however, sometimes installation does not proceed as expected and problems occur during and after installation. Occasionally it is necessary to rectify problems such as uncured soft liner from insufficient curing, bottom lift-up, ribs, pinholes, pokeholes, delamination, wrinkles, blockages due to liner shifting over openings, severed tie-ins at manhole locations, and non-advancement during inversions. This paper highlights several lining problems encountered in the field and offers trouble-shooting guidance. Experiences described herein include problems that occurred with CIPP and deformed & reformed HDPE liner installations. The review of these problems, remedial actions taken, and discussion of the lessons learned on the projects are intended to assist the engineer, owner, and contractor in taking appropriate actions to prevent potential problems and to correct problems on future projects. Field experiences from five (5) different lining projects are the basis of this paper.