No abstract

Influence of inter-granular void ratio on monotonic and cyclic undrained shear response of sandy soils Influence de l'indice des vides inter-granulaire sur la réponse monotone et cyclique non draine des sols sableux

No abstract

An experimental study, realized in laboratory with the triaxial apparatus, proposes to evaluate the influence of the mode of soil deposition, initial density and confinement on the undrained behavior of the Chlef sand. The tests were conducted on specimens collected in situ of initial relative density of 29 and 80% (corresponding to depths of 10 m and 20 m, respectively), with initial confining pressure of 50, 100 and 200 kPa using two depositional methods that include dry funnel pluviation (DFP) and wet deposition (WD) with water content of 3%. All the samples were subjected to a monotonic loading after the consolidation phase. The test results show that the initial confining pressure and the relative density affect considerably the resistance to liquefaction. However, it increases with the confinement and the density. The results also show that the samples prepared with the dry funnel pluviation method have a greater resistance to liquefaction than those prepared with the wet deposition method, by mobilizing higher residual strength. To cite this article: N.

Seismic scenarios are tools used to assess seismic risk at the city level. This allows the assessment of the vulnerability of exposed elements to risk (buildings, bridges, etc.). In the case of Chlef city (formerly El Asnam), this evaluation type proves to be useful given the seismic hazard to which it is exposed and the building park size. This city has been shaken in the past by several earthquakes including that of the El Asnam 1980 (Ms = 7.3), which caused hundreds of casualties and destroyed 70% of the city. In this paper, a seismic vulnerability assessment at urban scale and three seismic damage scenarios are simulated using the "RISK-UE" methodology. First, a recreation of the El Asnam 1980 earthquake, considering the urban conditions of the 1980s, is done. A difference of about 12% between observed and simulated damage is observed. Secondly, two senarios considering the current urban conditions are simulated then, vulnerabilty curves are developed. The simulations purpose is to detect the most vulnerable typologies and districts in the event of a similar earthquake and to provide decision support elements to the local seismic risk manager. The results show a structural damage decrease compared to the 1980 urban conditions.