When driving on a road embankment, we hope that it won’t collapse under the wheels of our vehicle, but how certain can we really be? <br /><br /> The changing climate may cause landslides and sinkholes to appear more often.<br /><br /> This edition of Futuris looks at how optical fibre sensors could help monitor the stability of roads, buildings, bridges and other constructions – and save lives. <br /><br /> A fibre optic future?<br /><br /> In Spain, engineers from a European research project called MULTITEXCO are testing an innovative method of accident prevention. <br /><br /> An embankment has been specially made of compacted soil for the experiment. <br /><br /> A special textile mesh is placed at several levels inside the structure.<br /><br /> “In general, this type of device has two functions: first, it can reinforce the construction, and second it can help to keep track of the deformations sustained by the structure,” explained Paolo Corvaglia, a materials engineer with D’Appolonia. <br /><br /> “In this specific experiment, we are measuring the deformations within the earthworks thanks to this fibre optical sensor, which is embedded within the textile mesh structure.”<br /><br /> It’s basically the same fibre-optic technology as what’s widely used in telecommunications, but in this case the thin cables are used as sensors. <br /><br /> To test how they work, the engineers flood the experimental embankment with water. <br /><br /> The structure deforms on the inside, putting pressure on the buried mesh. <br /><br /> The strain is transferred to the integrated sensors that can be read with special equipment.<br /><br /> We can place fibre optic sensors inside an embankment and read them periodically to find weak spots #Futuris pic.twitter.com/5uTWA4Iijn— Denis Loctier (@loctier) July 29, 2016<br /><br /> “The fibre optic sensor works like this: we send a beam of light through it, and analyse the reflected signal which tells us about the variations of the wavelength,” said Angela Coricciati, a materials engineer and D’Appolonia consultant.<br /><br /> “That makes it possible to determine the deformations of the sensor at every individual point along its length.”<br /><br /> Cool fact: fibre optic reflects light back; it can be read, making it a good temperature/pressure sensor #Futuris pic.twitter.com/vFGhNEWqqc— Denis Loctier (@loctier) July 29, 2016<br /><br /> The benefits<br /><br /> The researchers see many advantages of fibre optics compared to other sensors. <br /><br /> The fibres both collect and transmit data, simplifying the design. <br /><br /> They are also relatively inexpensive to use and immune to electromagnetic interference – that can be crucial in construction applications. <br /><br /> In addition, they are safe around explosives and flammable materials, as there’s no electric current inside.<br /><br /> “These sensors are very stable, they don’t require regular continuous re-calibration, and they sustain aggressive environments like geo-technical objects very well. And that makes long-term monitoring possible,” commented Corvaglia. <br /><br /> The idea is to embed smart textiles, with integrated fibre-optic sensors, into new elements of ro
