Geotechnical Investigations for Trenchless Projects: a Designer’s Perspective

Abstract

Geotechnical site investigations, associated laboratory testing and reports are often commissioned by authorities or their representatives early in a project’s life. The report(s) often looks very much like the last one, particular for small to medium sized projects. The geotechnical report(s) are used for a large variety of purposes including initial tendering, design of both permanent and temporary works, selection of equipment and in contract disputes. Reports often do not contain the required information because the person commissioning the investigation is unaware of what is required and/or assumes the geotechnical consultant knows. On the flip side the geotechnical consultant is often in a competitive bidding situation for the work and only offers what they believe the client may want. What is required is a set of guidelines that can be used to prepare a scope of work both for the investigation and for subsequent material testing but unfortunately there is not a lot of information readily available. This paper provides such guidelines based on the author’s own experience but also collates information contained in the published literature. The emphasis of the paper is from a pipeline designer’s perspective for the design of both the permanent and temporary works for trenchless pipeline installations. It is anticipated that the recommendations contained in this paper should result in much better information being available to trenchless contractors and contract managers alike.

Techniques