One pipe is pulled (slipped) into another, and in some cases, the annular space is then pumped with grout to seal off the new pipe into place.

Note: In the photos above, each HDPE pipe joint was fused together prior to pulling the line further into place


A cost saving alternative for digging up a culvert is to pull (slip) the line into place.  

Slip lining was the method chosen for the job in Rochester, NY in the photos above.  The existing line was a rough cut tunnel, so a line was pulled into place to replace the existing line.