Ian Moore Research

Pipe installation using directional drilling

IDM 27/7/05

Drilling machine for field monitoring program, Baumert (2003).

Load cell and data from metal gas pipe pull, Baumert (2003).

Directional drilling can be used to install new pipes without the surface disruption associated with trench excavation. Directional drilling involves excavation of a pilot borehole using a steerable drilling machine, extending from one location on the ground surface, down through the ground, and up to an exit point. The new pipe is then attached to the end of the drill string, and it is pulled back through the borehole. Issues requiring study include:

1. hydraulic fracturing of the soil around the borehole when drilling mud is used to stabilize the borehole;

2. the magnitude of pulling forces that develop

3. residual tensile pulling stresses and their effect on long term performance of new HDPE pipes

Working with Allouche, Brachman and Skinner, NSERC Strategic Research Grant funds have permitted Kennedy (MSc, 2004), to develop finite element analyses to examine hydraulic fracturing, and Baumert (PhD, 2003) and Allouche to develop and use load cells to monitor pulling forces and drilling mud pressures in the field. New procedures have been proposed to estimate pulling forces, considering the nature of the surrounding ground and construction quality.