Method for laying underground pipeline from access pit

摘要

A method for laying an underground pipeline, made from material which cannot sustain large thrust forces uses a thrust pipeline (17) with a boring head (15) to push the bore through the soil from an access pit (10). The thrust pipeline is positioned inside the pipeline to be laid and both pipelines have sections added as the bore is extended. The inside of the thrust pipeline is fitted with a screw transporter to remove soil cut away by the boring head. The target pit (11) for the pipeline need only be a small size. No pilot bore is required. The thrust pipeline is braced inside the outer pipeline by sliding supports.