Numerical Evaluation on Seismic Performance of an Integrated Slope Stabilisation System

Slope instability is a common geotechnical problem in South Gippsland, Victoria, Australia. An integrated slope stabilisation technique based on two well-developed methods, the embedded piles and the gabion-faced geogrid-reinforced retaining wall, has widely been adopted in this area to enhance the stability of slopes. Reinforced soil retaining walls are inherently flexible and are relatively insensitive to the shaking due to earthquake (Anastasopoulos 2010). Compared with the gravity-type retaining walls, the damage from the earthquake shaking to the reinforced retaining structures is relatively minor (Koseki et al. 1995; Tatsuoka et al. 1996; Bathurst and Hatami 1998). Several survived reinforced retaining walls after a destructive earthquake have also been recorded. A two-dimensional dynamic finite element analysis is conducted on the seismic behaviour of this integrated slope stabilisation method, in which the laterally loaded embedded pile can provide additional contribution to the stability of the slope. The behaviour of the soil and the gabion basket is simulated through the elastic-perfectly plastic constitutive model associated with the Mohr-Coulomb yield criterion. The embedded piles are shown to make a considerable contribution to the stability of the reinforced slope under the seismic condition. The effect of the friction angle and the cohesion of the clay soil on the seismic behaviour of the slope has been investigated. Overall, the performance of the integrated slope-stabilisation method reinforced slope studied in this paper is acceptable under the seismic loading conditions.

Keywords: Slope stabilisation, Seismic analysis, Pile retaining structure, Gabion-faced geogrid-reinforced retaining wall, Finite element method