Probabilistic assessment of seismic response of toe-excavated hillslopes retained using anchored sheet-pile-wall

Abstract

This paper reports the probabilistic seismic stability analyses conducted for toe-excavated hillslopes, both for unsupported slopes and that retained by anchored sheet pile wall system. Both pseudo-static and nonlinear dynamic analyses are carried out to decipher the seismic response of toe-excavated hillslope. It is found that due to incorporation of uncertainty in the soil parameters or seismic coefficients, slope sections otherwise rendered safe from deterministic analyses can exhibit significant probability of failure. Further study highlights that pseudo-static analysis overestimates the slope failure probability as compared to the nonlinear dynamic analysis. In this study, the probability of failure of the cut slope obtained from the nonlinear analysis (ranges between 21.4% and 70.1%, with a mean Pf value hovering at approximately 45%) is highly overestimated in a pseudostatic analysis, approximately in the tune of 68%. A significant effect of the correlation length characterizing the spatial variation of soil shear strength parameters on the seismic response of toe-excavated slopes is also manifested and reported. The present study shows that a cut slope retained with SPAR system exhibits a very low probability of failure for dimensionless correlation length value up to 0.1 under the cases of dynamic excitation.

Keywords

• Toe-excavated hillslope
• Pseudo-static analysis
• Nonlinear dynamic analysis
• Failure probability
• Spatial variability
• Sheet pile anchor retention system