牛圈沟高速滑坡特征及发生机理研究

发布时间：2019-05-12 04:16

【摘要】：“5·12”汶川特大地震诱发滑坡灾害多达15000多处,其中大型地震滑坡300余处。牛圈沟滑坡为典型的大型高速远程滑坡,该滑坡不仅规模巨大,而且呈现出许多与通常重力环境下产生的滑坡灾害迥异的特点,如触发地面震动、超常的高速抛射、异常高的流动性、超长的滑距等。本文通过研究牛圈沟高速滑坡的滑动特征,提出强震条件下牛圈沟高速滑坡的形成机理,认为其形成与滑坡体、滑床间的特殊部位—“锁固段”(类似于发震断裂带中应力集中的“锁固段”部位)突然被剪断的过程有关。由“锁固段”的突然剪断而触发的地面震动,我们称之为“滑坡地震”,并认为滑坡地震为牛圈沟滑坡启程剧动的重要产生机理。滑坡地震的震源就在滑体和滑床之间,对滑体启动方式及加速度具有零距离的直接影响,是发生启程剧动的最根本原因。据此,本文认为滑坡地震的产生是牛圈沟高速滑坡形成的本质机理,是滑体能够高速抛射的先决条件。(1)采用M.wyss方法估算滑坡地震震级及其释放的能量；通过理论计算,得出滑坡的启程速度及启动加速度的大小；(2)运用有限元软件,对牛圈沟滑坡启动过程进行数值模拟,模拟滑坡发生滑动的过程,得出牛圈沟滑坡启程剧动的相关数据和结论。(3)利用滑坡模型试验研究锁固段的面积大小在滑坡地震产生过程对滑体的影响,得到牛圈沟滑坡启程速度和锁固段之间的关系。世界上有关“滑坡地震”诱发自身高速滑动的研究少有报道。本论文从牛圈沟高速滑坡入手,提出了牛圈沟大型高速滑坡启程剧动机理的“滑坡地震”解释,不仅为该高速滑坡的研究提供了新的思路,还对地质灾害的防治具有指导性意义。
[Abstract]:There are more than 15000 landslides caused by the "May 12" Wenchuan earthquake, of which more than 15000 are large earthquakes. Niuqiangou landslide is a typical large-scale high-speed remote landslide. The landslide not only has a large scale, but also presents many characteristics that are very different from the landslide disasters produced in the usual gravity environment, such as trigger ground vibration and extraordinary high-speed ejection. Unusually high liquidity, ultra-long slippage, etc. By studying the sliding characteristics of Niuyuanggou high-speed landslide, this paper puts forward the formation mechanism of Niuyuanggou high-speed landslide under strong earthquake conditions, and considers its formation and landslide body. The process of sudden shear of the "locked section" (similar to the "locked section" of the stress concentration in the seismogenic fault zone) is related to the special position between the sliding beds. The ground vibration triggered by the sudden shear of the "locking section" is called "landslide earthquake", and it is considered that the landslide earthquake is an important mechanism for the beginning of Niuqiangou landslide. The focal point of the landslide earthquake lies between the slide body and the slide bed, which has a direct effect on the start-up mode and acceleration of the slide body, which is the most fundamental reason for the onset of the upheaval. Based on this, it is considered that the occurrence of landslide earthquake is the essential mechanism of Niuqiangou high speed landslide formation, and it is a prerequisite for the high speed ejection of slide body. (1) M.wyss method is used to estimate the magnitude of landslide earthquake and the energy released by it. Through theoretical calculation, the starting speed and starting acceleration of the landslide are obtained. (2) the start-up process of Niuqanggou landslide is simulated by finite element software, and the sliding process of landslide is simulated. The related data and conclusions of Niuqianggou landslide are obtained. (3) the influence of the area of locking section on the sliding body in the process of landslide earthquake is studied by using landslide model test. The relationship between the starting speed of Niuqanggou landslide and the locking section is obtained. There are few reports about the high speed sliding induced by landslide earthquake in the world. Starting with the Niuqanggou high speed landslide, this paper puts forward the "landslide earthquake" explanation of the starting mechanism of the Niuqanggou large high speed landslide, which not only provides a new idea for the study of the high speed landslide. It is also of guiding significance to the prevention and control of geological disasters.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.22

【相似文献】