FULL SCALE EXPERIMENTATION OF DISCONTINUOUS SUBSIDENCE FOR RAILWAY AND MOTORWAY EMBANKMENTS

The presence of subterranean cavities in soils in approved builing areas may lead to collapse with potentially serious consequences on the safety of people and property. A solution involving the use of reinforcing geosynthetic sheets, applied to the case of railroad and highway foundation layers, was tested on a fully instrumented experiment site. Localized collapse under the embankment was induced using a suction pump to evacuate reinforced cavities initially filled with expanded clay beads. Several reinforcement stiffness values were tested for cavity diameters of 2 and 4 meters (6.5 to 13 ft). In certain cases, traffic acceptance tests were performed. The results obtained show that the proposed reinforcement solution is likely to satisfy the changing and unforeseeable nature of localized sinkholes.