Applications of horizontal characterization techniques in trenchless construction

Horizontal site characterization technologies present a rapidly evolving alternative to traditional vertical site investigation methods for subsurface investigations of large diameter trenchless construction projects. A state-of-the-art review of horizontal site characterization tools, both currently available and under development, is presented. Additionally, a rational methodology for the selection and deployment of horizontal site investigation techniques in trenchless construction projects is also presented. The methodology enables the user to define and quantify the risks involved in a particular project, as well as to evaluate the degree to which these risks can be mitigated using various site characterization techniques. The proposed model is demonstrated using a working example. The paper concludes with a discussion of future trends in this exciting new field. The main conclusions drawn from this work are (1) adequate subsurface information is invaluable for underground construction; (2) site investigation programs of linear construction projects can be enhanced by horizontal characterization techniques; and (3) the availability of continuous and near-continuous subsurface information enables the utilization of new approaches for the analysis and representation of subsurface data.