The Trenchless Technique Horizontal Directional Drilling - Soil Related Risks and Risk Mitigation
Proceedings Publication Date
The horizontal directional drilling technique is very popular nowadays and the majority of the cables and pipelines installed with this technique succeed, but in several cases the technique still lacks sufficient control of risks coming from the underground. Therefore, a soil related-risks analysis for the prevention of unwanted events during the drilling stages or after the installation activities is recommended. The identification of the risks is the most important stage in the risk analysis. The identification of the risks requires sufficient knowledge of the processes during the drilling stages. Once all the risks are identified in a qualitative way the importance of risks can be determined. Very often calculations are necessary to classify the risk in a quantitative or semi –quantitative way. After classifying the risks, mitigation measures can be established for the significant risks. Since an overview of all possible risks in horizontal directional drilling would be extensive, this paper focuses on the most occurring soil related risks in horizontal directional drilling: (1) High pulling forces or incomplete pull back caused by local bore hole instability, (2) High pulling forces or incomplete pull back caused by frictional forces in the borehole and (3) Seepage through the borehole to the surface.