Seismic stability of reinforced-soil wall by pseudo-dynamic method

Abstract

Determination of the internal stability of reinforced soil walls under earthquake conditions is an important part of seismic design. The horizontal method of slices is used for determining internal stability or for tieback analysis of the reinforced soil wall. A pseudo-dynamic method is adopted in the present analysis, which considers the effect of phase difference in both the shear and primary waves travelling through the backfill due to seismic excitation. Reinforced soil walls with cohesionless backfill material have been considered in the analysis. Results are presented in graphical and tabular form to show the required tensile force and length of geosynthetic reinforcement to maintain the stability of the reinforced soil wall under seismic conditions. The effects of variation of parameters such as soil friction angle and horizontal and vertical seismic accelerations on the stability of the reinforced soil wall have been studied. With an increase of seismic accelerations in both the horizontal and vertical directions the stability of the reinforced soil wall decreases significantly, and thus greater strength and length of the geosynthetic reinforcement are required to maintain stability of the wall. The seismic vertical acceleration in an upward direction gives higher values of the required geosynthetic tensile strength, and the seismic vertical acceleration in the downward direction yields higher values of the length of geosynthetic reinforcement. Comparisons of the present results with available pseudo-static results are shown, and the limitations of the pseudo-static results are highlighted.

Development of rational seismic design method for geogrid-reinforced soil wall combined with fibre-mixed soil-cement and its applications

“…Huang et al (2003) investigated four geosynthetic-reinforced soil modular block retaining walls damaged during the 1999 Taiwan Chi-Chi earthquake, and performed back-analyses of their seismic stabilities using a modified two-wedge method. Nimbalkar et al (2006) examined the internal stability of reinforced slopes using a multilinear failure surface. In this analysis, pseudo-dynamic analysis (Steedman and Zeng 1990) was applied to consider both the shear and the primary waves propagating through the soil.…”

Stability of Reinforced Retaining Wall under Seismic Loads

“…In the figure, F N,I and F N,i+1 represent the normal force acting on the top and bottom of the ith slice, respectively; T i refers to the tensile force of the ith reinforcement [33]; Q hi and Q vi denote horizontal and vertical seismic force, respectively, acting on the top of the slice; α i is the inclination angle of slip surface of the slice in the horizontal direction; and W i is the weight of the ith slice. It should be noted that the slip surface is assumed to be a log spiral shape passing through the toe of the wall [34]. The sliding wedge is assumed to be in a limited equilibrium state, while both horizontal and vertical seismic loads are applied on the center of gravity of the slice.…”

Reliability Based Earthquake Resistant Design for Internal Stability of Reinforced Soil Structures

“…The most common approach to seismic stability evaluation of reinforced soil structures is the pseudostatic analysis, which is based on limit equilibrium methods (Leshchinsky and Boedeker 1989;Saran et al 1992;Leshchinsky and Kaching 1994;Bathurst and Cai 1995;Ling et al 1997;Ling and Leshchinsky 1998;Nimbalkar et al 2006;Nouri et al 2008). In the 1920s, Mononobe and Okabe developed this method to estimate the lateral earth pressures acting on retaining structures during earthquakes (Kramer 2003).…”