Conséquences du mode d'effondrement sur les mécanismes de transfert de charge et sur le dimensionnement des géosynthétiques sur cavités potentielles

Abstract : Consequence of the sinkhole mode on the load transfer mechanisms and on the design of geotextile-reinforced embankments overlying voids. The good geosynthetic sizing of the reinforcements on cavity requires a thorough knowledge of the mechanisms of load transfer of the zone of ground collapsed towards the stable zones. At present, the load acting on the geosynthetic sheet is estimated most of the time by using the mechanism of collapse proposed by Terzaghi and by supposing a uniform distribution of the stress on the sheet. To analyze more in detail these mechanisms of load transfer, full-scale experiments and DEM numerical simulations were performed. By testing two numerical processes, it was demonstrated that the cavity opening modes have a great influence on the shape of the load distribution transmitted to the geosynthetic sheet above the cavity and on the expansion mechanisms of the soil. An approximate conical load distribution seems well adapted when considering a progressive cavity diameter opening process, whereas an inverted load distribution seems more suitable for a gradual settlement process. In both cases and for the 20/40 mm used rolled gravel in the experimentation, the intensity of the load transfer mechanism can be approached by the Terzaghi's formulation using an appropriate value for the ratio between the horizontal and vertical stresses estimated at 1.3. The confrontation between the numerical and experimental results shows that all the complex mechanisms which are mobilized during the collapse of the ground on the geosynthetic is well enough taken into account in the numerical modelling (soil expansion, tension and displacement of the geosynthetic in the anchorage zones, distribution of load, etc.). An improvement of the design method is finally proposed from the results of this study with the consideration of a normative context including SLS and ULS calculations and with consideration of the safety factors.
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Contributor : Pascal Villard <>
Submitted on : Thursday, February 21, 2019 - 12:57:43 PM
Last modification on : Tuesday, November 19, 2019 - 12:35:10 PM

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Pascal Villard, Laurent Briançon, Audrey Huckert, Philippe Delmas. Conséquences du mode d'effondrement sur les mécanismes de transfert de charge et sur le dimensionnement des géosynthétiques sur cavités potentielles. Revue française de Géotechnique, 2017, pp.2. ⟨10.1051/geotech/2017013 ⟩. ⟨hal-02007017⟩

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