Applications of horizontal characterization techniques in trenchless construction

Horizontal site characterization technologies present a rapidly evolving al ternative 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 currentl y available and under development, is presented. Additionally, a rational m ethodology for the selection and deployment of horizontal site investigatio n techniques in trenchless construction projects is also presented. The met hodology enables the user to define and quantify the risks involved in a pa rticular project, as well as to evaluate the degree to which these risks ca n 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 conclusion s drawn from this work are (1) adequate subsurface information is invaluabl e for underground construction; (2) site investigation programs of linear c onstruction projects can be enhanced by horizontal characterization techniq ues; 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.