Interpretation of vane shear tests for geotechnical stability calculations

In this note we consider the problem of calibrating failure criteria for short-term stability calculations based on the results of vane shear tests. Numerical and theoretical considerations supported by experimental data provide evidence that we can use the vane shear test to obtain the undrained strength of a sample tested under simple shear conditions at a normal stress equal to the horizontal effective stress at the given depth. Consequently, it is argued that there is no need to correct the field vane undrained strength to obtain the mobilized strength for embankment stability calculations, provided that soil strength is normalized to the normal effective stress acting on the slip surface and rate effects are properly considered.Wefurther show that the standard Tresca failure criterion, albeit simplistic, will provide reasonable estimates of the mobilized strength if properly calibrated against field vane tests

Review of Soil and Topography Effects in the September 7, 1999 Athens (Greece) Earthquake

The earthquake that hit Athens, Greece on September 7, 1999 was an unexpected disaster. It originated from a previously unknown seismotectonic structure, at about 18 km to the west of the historical center, and left behind 143 casualties, about 100,000 homeless and 100 totally collapsed buildings. On the other hand, it provided a number of reliable strong motion recordings and well-defined patterns of damage at sites with known geological and geotechnical conditions. Evaluation of this information shows that the very stiff soils of the Athens basin amplified seismic ground motion by an average of 40% compared to nearby outcropping soft rocks. In addition, the 40m in height, 15-3O° inclination cliffs of Kifissos river canyon may have aggravated the seismic motion by an additional 50% on average. Modem seismic codes totally oversee the first of these effects and underscore the second