【摘要】 2008年汶川地震触发的大光包滑坡是世界上罕见的巨型滑坡。滑坡后暴露长达1.8km的剪滑光面,光面上发育厚度达3 m的碎裂岩带,带内岩体不但存在先期碎裂,而且地震中产生了大量新碎裂。大光包滑坡独特地质现象和复杂形成机制受到国内外持续争论和广泛研究。本文在已有研究基础上,总结10年调查成果,建立大光包滑坡地质原型:该滑坡是碳酸盐岩地层内由先期层间构造错动带控滑的地震大型滑坡。进一步将该错动带概化为软弱层带,开展含软弱层带地质体的振动台模型试验;结果表明,振动过程软弱层带与顶底硬层产生非协调变形,在软弱层带内形成强大振动冲压–张拉和振动剪切力,使得带内土压力较顶底硬层显著放大,并将这类动力学行为概括为动力非协调变形响应。从而认为,动力非协调变形致损是大光包滑坡滑带岩体震裂成因,以此提出,强震过程软弱层带非协调变形与岩体动力致损可能诱发了大光包滑坡失稳启动。更多还原

【Abstract】 Daguangbao(DGB) landslide,with a 3 m deep fragmented rock zone at 1.8 km long sliding surface,is a gigantic landslide triggered by 2008 Wenchuan earthquake. The fragmented zone formed due to historical tectonic motion and Wenchuan earthquake. Because of the unique and complexity,DGB landslide is wildly studied over the world. Based on 10 years′ investigations,a geological model of DGB landslide was proposed. DGB landslide was a gigantic earthquake-induced landslide in carbonate strata and shear failure was triggered in a bedding fault. Shaking table model test was conducted with a weak layer simplified from the bedding fault. The results reveal that the deformations of the weak layer and the upper hard layer are discordant during vibration and the discordant deformation results in vibrating compression-tension or vibrating shearing pressure within the weak layer. It was concluded that rock fragmentation within the shear zone is ascribed to the discordant deformation response of the bedding fault and that the discordant deformation of the bedding fault and the corresponding rock dynamic damage trigger DGB landslide.更多还原