Determining the optimum level of investigation for a trenchless installation project - how much is just enough?

With the increasing demand for, and application of, Trenchless installation methods for pipeline replacement and rehabilitation projects, it is prudent to consider what and how much investigation needs to be carried prior to construction for a trenchless project. This paper will consider and discuss the answer to this question, from a risk management basis, whilst also looking at what different investigations need to be undertaken for a trenchless installation project as opposed to the more traditional open trench replacement.

The paper will consider a range of typical trenchless installation methods from small bore HDD to large bore Maxi Rigs and similarly for small and large bore pipeline rehabilitation in a variety of different situations and locations. It will then look at the risks to the Client, in terms of cost, time, exposure and customer perception, by not completing adequate investigation. The paper will also discuss potential mitigation and management options for these risks.

There is no one simple answer, due to the differing nature’s of the various types of trenchless installation projects. However matrices can be developed that give Client’s an understanding of their risk exposure and strategies to manage these risks.