Role of Instrumentation in Assessment of Complex Ground Conditions

Slope indicators are commonly used in the evaluation and assessment of ground conditions affecting the highway infrastructure of roads and bridges when historic evidence, airphoto interpretation or judgment suggest that the natural or existing ground might develop instability problems through new construction or natural processes. During the planning and design stages of the re-alignment of two major Primary Highway routes in the Southern Region of Alberta, office studies and site reconnaissance indicated the possibility of slope instability concerns. These concerns warranted the installation of slope indicators to determine their validity and measures, if any, to ensure the suitability of the proposed routes. The slope indicator monitoring concurred with the projections of the site and office reviews allowing decisions to be made to ensure construction of the bridges and highways in stable terrain. These two case studies demonstrate the importance of using instrumentation to validate site observations and opinions, and to allow for sound decision-making.