Method and apparatus for underground pipeline installation

1 . A method for installing an underground pipe using a ground piercing tool having an elongated tubular tool body, a striker disposed for reciprocation within an internal chamber of the body to impart impacts to an impact surface for driving the tool forwardly through the ground, and an expander having a diameter greater than that of the tool body, comprising the steps of:

securing a tubular shroud to the expander so that the ground piercing tool is disposed inside of the shroud;

operating the tool in forward mode over a run so that the impact tool and shroud move forward;

fitting a front end of a replacement pipe into sliding engagement with a rear end of the shroud; and

pushing the replacement pipe from a rear end portion thereof in a manner sufficient to insure that a front end of the replacement pipe remains in sliding contact with the shroud as the tool moves forward.

2 . The method of claim 1 , wherein a front end portion of the replacement pipe is slidingly received inside the shroud.

3 . The method of claim 1 , wherein the impact tool bursts an existing pipeline during the run.

4 . The method of claim 3 , further comprising:

when the tool has reached a receiving pit at the end of the run, removing the nose of the tool from the expander and disconnecting the expander from the pipe; and

removing the ground piercing tool from the pipe by moving it in a rearward direction through the newly installed pipe.

5 . The method of claim 4 , wherein the receiving pit comprises a manhole.