DETERMINATION OF SEISMIC BEARING CAPACITY AND FAILURE MECHANISMS FOR SHALLOWS PLACED ADJACENT TO SLOPES

In this paper, an analytical method is developed for calculating ultimate bearing capacity of foundations adjacent to slopes. This subject is highly dependent on the slope geometry and soil properties. Seismic forces are applied to the soil mass, soil surcharge and foundation by pseudo-static forces. In this study, a rigorous assessment of the seismic bearing capacity is performed using an upper-bound limit state plasticity framework known as discontinuity layout optimization (DLO), which makes few prior assumptions concerning the failure geometry. The results show that soil properties, slope configuration, and pseudostatic seismic loading all influence the realized failure mechanism and associated bearing capacity. The use of bearing capacity coefficients that fit within the conventional superposition method may underestimate limit loads when the underlying soil provides a relative increase in resistance but may greatly overestimate bearing capacity when the self-weight of the soil is destabilizing in nature. A set of design charts using direct computational methods for a variety of geometric, geotechnical and seismic conditions is provided. The main objective of this technical note is to explore the influence of horizontal pseudostatic seismic coefficients on the failure mechanism and the ultimate load for footings located near slopes. The suitability of bearing capacity factors compatible with the superposition method for analysing the capacity of footings near slopes subject to seismic conditions is discussed. Finally, a set of design charts is presented.

کلیدواژه ها:

Bearing capacity ، Earthquakes ، Slopes ، Foundations ، Failure mechanism