Current methods for stability analysis of slopes subjected to seismic loading are based on the pseudo-static approach which introduces an equivalent static force to describe the effects of the transient seismic action. This force is typically defined through an equivalent seismic coefficient, kh,Eq. The result of a pseudo-static stability analysis critically depends on the adopted value of kheq whose selection is to a certain extent arbitrary and lacks a clear rationale. Alternatively, seismic stability condition and post-seismic serviceability of slopes can be evaluated using displacement-based approaches in which earthquake-induced slope displacements are compared with threshold values representing the maximum displacement that can be tolerated by the slope before reaching a limit state. The tolerable slope displacement is related to damage associated with slope instability, this depending on the behaviour of the slope and of the structures and infrastructures interacting with it. Pseudo-static and displacement-based analyses have been usually regarded as alternative methods for evaluating seismic slope stability. However, the equivalent seismic coefficient to be used in the pseudo-static approach may be related to earthquake-induced displacements. In fact it is possible to introduce a rational criterion to make the results of the pseudo-static approach equivalent to those of a displacement-based analysis and it is possible to detect the value of the seismic coefficient leading to this equivalence. In the proposed method, limit values of tolerable slope displacement dlim, related to ultimate and/or a serviceability limit states are to be defined and a displacement regression model is required. In the paper, the above procedure is adopted to detect reliable relationships between the equivalent seismic coefficient kh,eq and limit values of tolerable slope displacements. The proposed relationships were derived by different empirical regression models, using a database of Italian strong motion records. The adopted regression models are also compared with similar relationships recently derived. Finally, the proposed relationships between kh,eq and dlim are discussed in the light of provisions for the Italian building code (D.M. 14.01.08).

Valutazione del comportamento dei pendii in condizioni sismiche

BIONDI, Giovanni;CASCONE, Ernesto;
2011-01-01

Abstract

Current methods for stability analysis of slopes subjected to seismic loading are based on the pseudo-static approach which introduces an equivalent static force to describe the effects of the transient seismic action. This force is typically defined through an equivalent seismic coefficient, kh,Eq. The result of a pseudo-static stability analysis critically depends on the adopted value of kheq whose selection is to a certain extent arbitrary and lacks a clear rationale. Alternatively, seismic stability condition and post-seismic serviceability of slopes can be evaluated using displacement-based approaches in which earthquake-induced slope displacements are compared with threshold values representing the maximum displacement that can be tolerated by the slope before reaching a limit state. The tolerable slope displacement is related to damage associated with slope instability, this depending on the behaviour of the slope and of the structures and infrastructures interacting with it. Pseudo-static and displacement-based analyses have been usually regarded as alternative methods for evaluating seismic slope stability. However, the equivalent seismic coefficient to be used in the pseudo-static approach may be related to earthquake-induced displacements. In fact it is possible to introduce a rational criterion to make the results of the pseudo-static approach equivalent to those of a displacement-based analysis and it is possible to detect the value of the seismic coefficient leading to this equivalence. In the proposed method, limit values of tolerable slope displacement dlim, related to ultimate and/or a serviceability limit states are to be defined and a displacement regression model is required. In the paper, the above procedure is adopted to detect reliable relationships between the equivalent seismic coefficient kh,eq and limit values of tolerable slope displacements. The proposed relationships were derived by different empirical regression models, using a database of Italian strong motion records. The adopted regression models are also compared with similar relationships recently derived. Finally, the proposed relationships between kh,eq and dlim are discussed in the light of provisions for the Italian building code (D.M. 14.01.08).
2011
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11570/1911146
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