【摘要】 摩岗岭滑坡位于泸定县境内的大渡河右岸一级支流磨西河口,为18世纪四川西部强震诱发的巨型地震高位滑坡.研究揭示,该滑坡发育于高烈度区的康定杂岩中,河谷走向与区域最大主应力方向垂直,河谷下切过程中斜坡经历了强烈的浅表生卸荷回弹,形成高陡斜坡后,谷坡在河谷应力场(重力场)的长期作用下坡体浅表层沿与缓倾坡外的结构面、走向北北西的陡倾结构面(与坡面走向一致)分别发生滑移和拉裂,当河谷切穿得妥断裂后,断裂带塑性变形,牵动上部坡体表层发生压缩-剪胀错动变形;周期性强震的反复作用,滑移和拉裂成脉动式和累进性式发展,最终使上述两组结构面接近贯通状态,上下游北东和北向侧裂面的切割,为坡体大规模失稳奠定了基本条件.1786年强烈的地震、高位地形放大效应、背坡效应等因素叠加最终触发摩岗岭滑坡的发生.更多还原

【Abstract】 Mogangling landslide,located on the right bank of Daduhe River,is a seismic landslide with high location,which triggered by strong earthquake in 18th century at western Sichuan Basin.Research reveals that,the landslide is developed in the Kangding complex strata,where the flow direction of Daduhe Rive is perpendicular to the regional maximum geo-stress.During the cutting of the Daduhe River,the slope underwent the epigenetic unloading and elastic rebounding,forming high slope,furthermore,under the river stress field time-dependent action,the slope began the slip-crack in tension by the action of structural planes and the slope surface,when the Daduhe River cut through the Detuo fault,plastic deformation happened in the fault zone,and compression-dilatancy deformation emerged in the slope upon the faul.As the periodicity strong earthquake action,the slip-crack in tension developed in progressivity and in pulsating movement made the steep structural plane nearly through.For the lateral edge structural planes exist,presenting the condition for a huge high-locality landslide.As expected,the earthquake in 1786 triggered the Mogangling high-locality landslide under the co-action of strong earthquake,topography amplification and opponent slope effect.更多还原