[H-DS05] Landslides and related phenomena

[HDS05-P09] Effect of weak interlayer on seismic failure of bedding slopes using shaking table tests

*Hailong Yang¹, Xiangjun Pei², Shenghua Cui², Issei Doi³, Gonghui Wang³ (1.College of Environment & Civil Engineering, Chengdu University of Technology, China, 2.State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, China, 3.Disaster Prevention Research Institute, Kyoto University, Japan)

Keywords:weak interlayer, PGA amplification, failure mode, bedding slopes, shaking table test

Weak interlayer, as the potential basal slip surface of a deep-seated bedding landslide, has been constantly focused on its effects on the seismic response and failure characteristics of the rock slopes. In this study, shaking table tests are performed for two model slopes with different weak interlayers consisting of homogeneous weak interlayers and weak interlayers with discontinuous interfaces. The seismic response and deformation of two model slopes are monitored by using embedded sensors and digital image correlation (DIC) technology. The model test results show that the weak interlayer with discontinuous interfaces restrains slope’s PGA amplification, weakens tensile deformation on the potential tensile release surface, and enhances the shear stress generated in the weak interlayer near the slope toe. The V-shaped tensile failure occurred in the model slope with homogeneous weak interlayers, that is, the tensile failure observed at the slope crest is generated earlier than the basal shear failure. However, Λ-shaped tensile failure is observed in another model slope. The basal shear failure first is formed in the discontinuous interfaces developed weak interlayer, and then Λ-shaped tensile failure occurred, resulting in difficulty in early deformation identification of the instability slope. In summary, our test results suggest that the characteristics of weak interlayer should be considered in the failure mode prediction of coseismic landslide.