基于环剪试验的汶川地震大型滑坡启动机理探索

发布时间：2018-03-07 13:13

本文选题：牛眠沟滑坡　切入点：汶川地震　出处：《岩土工程学报》2017年12期 　论文类型：期刊论文

【摘要】：2008年5·12汶川地震触发了大量滑坡灾害,牛眠沟滑坡是发生于震中的同震大型滑坡。经过现场调查,该滑坡启动后即与对岸山梁相撞并产生20 m爬高,估算速度达19.8 m/s,表现出高速启动特征。取滑带材料进行室内环剪试验,结果表明试样在不排水条件下具有很高的剪切液化能力,且动剪应力下容易液化,液化后材料视摩擦角仅为9.4°,从而得出地震滑带材料液化可能导致牛眠沟滑坡高速启动。通过能量方法,估算了不排水动剪试验材料的液化能量和地震过程通过滑带的地震能量。结果表明,滑带材料破坏所需峰值加速度为192 gal,液化所需能量为2.3×10~4J/m~2;汶川地震沿滑带方向提供最大地震加速度为799 gal,从而满足滑带液化的能量条件,并推测滑坡可能在地震初期突然触发。
[Abstract]:2008 Wenchuan earthquake triggered a large number of landslide disasters, Niumiangou landslide occurred in the epicenter of a large landslide. After the site investigation, the landslide immediately collided with the other side of the mountain beam and generated 20 meters climbing. The estimated speed is 19.8 m / s, showing the characteristics of high speed starting. The results of indoor annular shear test show that the sample has a high shear liquefaction capability under undrained conditions and is easy to liquefy under shear stress. After liquefaction, the apparent friction angle is only 9.4 掳, and it is concluded that the liquefaction of seismic slip zone materials may lead to the high speed start-up of Niu Mian Gou landslide. The liquefaction energy of the undrained dynamic shear test material and the seismic energy of the seismic process passing through the slip zone are estimated. The peak acceleration required for material failure in slip zone is 192 galand the energy required for liquefaction is 2.3 脳 10 ~ 4 J / m ~ (2), and the maximum acceleration of Wenchuan earthquake is 799 galalong the direction of slip zone, thus satisfying the energy condition of liquefaction of slip zone, and it is speculated that the landslide may be triggered suddenly in the early period of earthquake.
【作者单位】：地质灾害防治与地质环境保护国家重点实验室(成都理工大学);京都大学防灾研究所;
【基金】：国家创新研究群体科学基金项目(41521002) 国家自然科学基金项目(41572302)
【分类号】：P642.22

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