Sewergeek.com
Various Repair Methods Explained
Soil Displacement Method (moles)
Most of these are links to other sites like nodig-construction.com, that have already done a good job of explaining these methods. Take some time and look atwhat else they have to offer.
A pneumatic hammer, creates an underground cavity in order to pull short or long pipes made of plastic or metal under roadways or other obstacles. This is usually limited to smaller pipe sizes, (approx. 3 ft. or less), and shorter runs (a few hundred feet), but the limits have been significantly improving. This method is more difficult, but can still be done in loose soils.
A method of installing communication cables in existing sewer lines to eliminate the need for trenching.
Use of a "Vactor" type truck and an air pressure lance to remove soils from around delicate utilities. Unlike Hydo-Excavation, this method does not use water. Giving the advatage of clean usable fill removed from the excavation.
Using a hydraulic ram pulled through the old pipe to vibrate and burst the old pipe so an equal or larger diameter pipe can be pulled through from behind to replace the old pipe.
A felt liner impregnated with resin is installed in the existing sewer and inverted (as if unroling a sock), to allow it to conform to the sides. Another flexible plastic liner is inserted into the pipe and the resin is heated to cure into a solid liner. This method is excellent for hdraulic repairs, but does not add any significant structural strength to the pipe.
A High Density Plyetheyne pipe that is pulled through an existing pipe and fused together to form a complete seamless pipe. The pipe is actually the same size, or slightly larger in diameter than the original pipe. It is temporarily shrunk to allow it to be puled through, then it is allowed to expand inside the ipe ofr a tight fit.