Fibre Optic Sensors for Geotechnical Applications

Major structures (dam, bridges) and civil infrastructure (roads, railways, buildings) rest on granular materials: soils and sediments, that cover 90% of the Earth's surface. This layer of material is also the source of many natural hazards such as landslides, subsidence, and liquefaction. Rapidly changing climatic conditions have the capacity to alter profoundly ground and soil settings and stability, increasing risk and endangering safety of the infrastructure. For example, global warming is destabilising permafrost-cemented alpine slopes and denser rainfalls have led to greater frequency of landslides and building subsidence. The aging of the civil infrastructure creates new problems, as they have proved frail to the impact of extreme events, with heavy financial and human costs. Even small scale events such as train delays resulting from the failure of railway cuttings during intense rainstorms are more frequent and very costly.The routine monitoring of soil conditions during planning, construction and operation allows the anticipation and mitigation of hazards. This requires intelligent monitoring systems that can deliver reliable information about important soil properties that control soil stability, coupled with alarm systems capable of giving early warning of potential failure. In this project we will use optical fibres to form networks of sensors that measure many properties of soils and granular materials, that will allow an assessment of their stability, point to ways of improving stability, and provide early warning of potential problems. The porject wioll require input from many different areas of science and engineering to make these sensors robust enough to survive the harsh environments in which they will be used.