Evolution in Trenchless Technology for Rehabilitation and Microtunnelling Installation of Drains and Sewers

The trenchless methods of rehabilitation and installation of cables and pipes have gone through a massive period of development in the past 25 years. Gravity drains and sewers in the non-man-accessible region have benefited greatly from this development. Depending on outside limiting factors, the methods that have been tried and have proven themselves on the market make it possible, to repair and renovate pipelines from the inside and to replace them underground in the same line path as well as to install new lines in a trenchless manner almost independently of the line-specific, geological and hydro-geological limiting conditions. In this discussion, the most important developments in this field are portrayed and the most important current tendencies of further development are described.