Keywords: seismic hazard, fault rupture, slope stability, permanent deformations, sliding, geosynthetics, reinforcement.

The construction of geosynthetically reinforced structures presents a significant growth over the last decades. Geosynthetics have been effectively applied in various geotechnical, transportation, hydraulic and geoenvironmental projects [1,2]. The socio-economica and environmental consequences related to a potential failure of such large-scale infrastructures due to man-made and natural hazards, mainly earthquakes, can be vast and should be minimized. In general, seismic distress of geostructures may arise due to: (a) seismic wave propagation, and (b) permanent deformations developed during an abrupt fault rupture. Consequently, seismic loading on geostructures (embankments, earth-dams, landfills) may be expressed either as slope failure of the soil/waste mass or as excessive permanent deformations. Since reinforcement is one of the main functions of geosynthetics, it is evident that their contribution in the prevention of potential seismic instabilities is valuable [3,4]. Moreover, many types of geotechnical works (landfills, retaining walls) include geosynthetics, which among others play an important role in the dynamic distress of the infrastructure. Nevertheless, current seismic design procedures most frequently employ pseudostatic methods. Hence, seismic design of these critical infrastructures does not consider several crucial factors, like the compound failure and the global stability which were observed in damaged structures after post earthquake investigation. Recent earthquakes, such as the 1999 Kocaeli and the 1999 Chi-Chi incidents, have revealed the seismic vulnerability of mechanically stabilized earth walls and reinforced slopes.

Therefore, geotechnical engineers should pay extra attention to the aforementioned crucial issues to ensure the integrity of the whole system and particularly the geosynthetics. By taking advantage of the reinforcing effect of the geosynthetics the potential problems may be substantially reduced or even avoided. This study aims to demonstrate the effectiveness of the geosynthetics as seismic mitigation measures for geostructures and to assess their impact on the dynamic response of reinforced soil structures. For this purpose, the potential failure modes are initially identified utilizing the methods commonly employed for dynamic response and slope stability assessment. Subsequently, parametric finite element analyses are conducted and the impact of the most important parameters on the examined application is assessed. In accordance, several reinforcement scenarios are examined and analyzed following the same procedures. The efficiency of geosynthetics on the prevention of slope instabilities and the reduction of the anticipated stress levels on the geostructures is highlighted. Results strongly indicate that geosynthetics can mitigate the seismic hazard of geostructures and provide a reliable reinforcement measure for various applications in geotechnical earthquake engineering practice.

[1]

R.M. Koerner, "Emerging and future developments of selected geosynthetic applications", Journal of Geotechnical and Geoenvironmental Engineering, 126(4), 291-306, 2000. doi:10.1061/(ASCE)1090-0241(2000)126:4(293)

[2]

FHWA, "Mechanically stabilized earth walls and reinforced soil slopes design and construction guidelines", National Highway Institute, Office of Bridge Technology, Federal Highway Administration, USA, 2001.

[3]

M.K. Yegian, U. Kadakal, M. Catan, "Geosynthetic for earthquake hazard mitigation", Proceedings of Geosynthetics '99, Boston, Mass., April, 1999.

[4]

P. Georgarakos, M.K. Yegian, G. Gazetas, "In-ground isolation using geosynthetic liners", 9th World Seminar on Seismic Isolation, Energy Dissipation and Active Vibration Control of Structures, Kobe, Japan, June, 2005.

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