A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
What Value of Interface Friction to Select for Geosynthetic Liner on Landfill Slopes?
Nowadays, the use of geosynthetics is a common practice in landfill barriers. Since the landfill liner systems are even steeper, an appropriate characterization of the mechanical properties of the interfaces is required for their stability analysis. In this contest, the appropriate determination of the interfacial frictional properties is necessary. In this work, the mechanical characterization of a typical interface found in landfill barriers is presented and discussed. In fact, the experimental assessment of geocomposite drain (GCD) - geomembrane (GMB) interface is particularly important since its use is become even more widespread. To assess its performance, also the effect of the two different materials which form the composite layer (geonet and geotextile) is examined separately. For this purpose, the three procedures "Standard", "Displacement" and "Force" are carried out. The results indicate that all combinations of geosynthetics tested with HDPE smooth geomembrane, exhibit a typical behavior of gradual sliding and, in particular, a stick-slip behavior for GNT - GMB and GCD - GMB interfaces. Following the test sets on GNT-GMB and GTX-GMB, it could be deduced that the behavior of GCD-GMB interface, where the Geotextile GTX is in direct contact with the Geomembrane GMB, is influenced by the Geonet GNT support. In conclusion, based on test results, it could be noticed that: (1) "Standard Procedure" is not rigorous because a static approach is proposed for kinematic conditions. Moreover, this interpretation overestimates the interface friction angle, overall in the case of gradual sliding, compared to the static ones. (2) Thanks to the "Displacement" and the "Force" Procedures it is possible to study accurately the interface friction during different phases of the test. Anyway, it is worth noting that the corresponding friction angles are calculated in different kinematics conditions. In particular, the interface friction angle Φs is determined taking into account the acceleration during the slide (dynamic conditions of the upper box) while δlim corresponds to a static state of the upper box after large displacements. Test results show that the kinematic conditions could influence the interface friction angles. For this purpose it is important to relate the conditions found during the laboratory tests with the existing situations on site. Finally, it is necessary to answer to the outstanding question about the selection of the interface friction angle that could lead to an appropriate value for a safe design.
What Value of Interface Friction to Select for Geosynthetic Liner on Landfill Slopes?
Nowadays, the use of geosynthetics is a common practice in landfill barriers. Since the landfill liner systems are even steeper, an appropriate characterization of the mechanical properties of the interfaces is required for their stability analysis. In this contest, the appropriate determination of the interfacial frictional properties is necessary. In this work, the mechanical characterization of a typical interface found in landfill barriers is presented and discussed. In fact, the experimental assessment of geocomposite drain (GCD) - geomembrane (GMB) interface is particularly important since its use is become even more widespread. To assess its performance, also the effect of the two different materials which form the composite layer (geonet and geotextile) is examined separately. For this purpose, the three procedures "Standard", "Displacement" and "Force" are carried out. The results indicate that all combinations of geosynthetics tested with HDPE smooth geomembrane, exhibit a typical behavior of gradual sliding and, in particular, a stick-slip behavior for GNT - GMB and GCD - GMB interfaces. Following the test sets on GNT-GMB and GTX-GMB, it could be deduced that the behavior of GCD-GMB interface, where the Geotextile GTX is in direct contact with the Geomembrane GMB, is influenced by the Geonet GNT support. In conclusion, based on test results, it could be noticed that: (1) "Standard Procedure" is not rigorous because a static approach is proposed for kinematic conditions. Moreover, this interpretation overestimates the interface friction angle, overall in the case of gradual sliding, compared to the static ones. (2) Thanks to the "Displacement" and the "Force" Procedures it is possible to study accurately the interface friction during different phases of the test. Anyway, it is worth noting that the corresponding friction angles are calculated in different kinematics conditions. In particular, the interface friction angle Φs is determined taking into account the acceleration during the slide (dynamic conditions of the upper box) while δlim corresponds to a static state of the upper box after large displacements. Test results show that the kinematic conditions could influence the interface friction angles. For this purpose it is important to relate the conditions found during the laboratory tests with the existing situations on site. Finally, it is necessary to answer to the outstanding question about the selection of the interface friction angle that could lead to an appropriate value for a safe design.
What Value of Interface Friction to Select for Geosynthetic Liner on Landfill Slopes?
Carbone, Laura (author) / Gourc, Jean-Pierre (author) / Briancon, Laurent (author) / Moraci, Nicola (author) / Carrubba, Paolo (author)
2013
9 Seiten, Bilder, Tabellen, Quellen
Conference paper
Storage medium
English
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