Influence of Wrap-Around Facing Types on the Seismic Response of Reinforced Loess Slopes: A Comparative Study of Two Seismic Waves

To promote the application of wrap-around reinforced soil structures in high-intensity seismic regions, this study systematically investigated the influence of different wrap-around facing types on the seismic performance of reinforced loess slopes. Through shaking table model tests, the dynamic responses of three wrap-around facing types—C-shaped wrap-around facing, secondary-reinforcement wrap-around facing, and self-wrap facing—under the excitation of two seismic waves (El Centro wave and Wenchuan Wolong wave) were compared and analyzed. The test introduced the marginal spectrum energy analysis method to accurately identify the location and evolution process of slope damage. The results indicated that reinforcement significantly enhances the global integrity of the slope, yet the influence of the wrap-around facing type on seismic performance is significant. The C-shaped wrap-around facing exhibited the best global stability and seismic performance, with damage initiating inside the slope body and a good energy dissipation mechanism. The secondary-reinforcement wrap-around facing is prone to stress release and local loosening in the slope crest region due to weak constraints. The self-wrap facing has insufficient restraint at the top, where the reinforcement tends to experience pullout. Compared with the El Centro wave, the Wolong wave, rich in long-period components, induced stronger dynamic responses, resulting in greater slope face displacement, acceleration amplification, marginal spectral amplitude, and reinforcement strain. Significant damage in the slopes initiated in the mid-upper region, and the damage pattern was directly related to the wrap-around facing type. The research findings provide a theoretical basis for the optimal design of reinforced loess slopes in high-intensity seismic zones.