Abstract: An improved form of intermediate sleeve for installing a pipeline by forcing pipes into earth, incorporating the sleeve into the resulting pipe assembly at an intermediate portion thereof, and pushing the rear end of the pipe assembly and telescopically extending the sleeve alternately in repetition to thereby propel the assembly. The intermediate sleeve comprises a socket member, a spigot member slidably fitting in the socket member and includes a sealing portion in the vicinity of a sliding portion between the members. The intermediate sleeve is usable as part of the pipeline after the completion of the propulsion without the necessity of providing any additional special seal. The intermediate sleeve can be equipped with a feeder device for feeding a lubricant into the sliding portion and for withdrawing the same therefrom during collapsing movement to completely prevent the ingress of soil or sand into the sliding portion.