Horizontal sampling: A new direction in site characterization

Traditionally, sampling and monitoring of potentially contaminated soils an d ground water has been achieved using vertical drilling technology. Howeve r, vertical drilling presents several technical limitations, including the need to position the drilling rig directly above the target zone and the ri sk of cross-contaminating laterally stacked aquifers. These limitations may be overcome using horizontal directional drilling technology. This paper gives a short introduction to horizontal directional drilling eq uipment and installation techniques, followed by an overview of existing ho rizontal sampling tools. Details for the development of a horizontal multip le port soil sampler are outlined and the future role of horizontal samplin g in site investigation is discussed. It is concluded that horizontal direc tional drilling technology has many applications in site investigation, off ering an efficient and cost-effective method of collecting geotechnical and gee-environmental data, both as an alternative and as a complement to vert ical drilling and sampling technologies. (C) 1998 Elsevier Science Ltd. All rights reserved.