Recently, more and more structures are being built in soft ground and coastal reclaimed land. This often leads to the problems of negative friction generated by the settlement of ground due to earth consolidation.
A technique, successfully utilized in countries such as Netherlands, England and Japan for reduction in negative friction is be the use of Slip lay pipe. About 6mm thick of bituminous material is applied to the pipe surface in order to minimize the negative friction by means of its visco elastic characteristic. The effectiveness of slip layer pipe not only produces a sound foundation in areas of intense ground subsidence but also helps to achieve tremendous cost saving.

Typical composition of slip lay pipe is shown below: