红石岩地震滑坡的运动过程离散元模拟分析

发布时间：2018-05-20 02:39

本文选题：离散元 + PFC　；参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：2014年8月3日,云南省昭通市鲁甸县发生6.5级地震,造成牛栏江红石岩村附近右岸山体发生滑塌,并阻塞牛栏江,形成堰塞湖,淹没了上游的红石岩水电站首部枢纽。本文以红石岩地震滑坡为例,基于离散元颗粒流软件PFC对该滑坡的运动过程进行了模拟,对滑坡的启动机制、运动路径、运动速度和堆积范围等进行分析和探讨,主要工作内容和成果有:(1)针对PFC建立滑坡模型前处理方面较弱的问题,以2014年地震触发的红石岩滑坡为例,以Brick填充法为基础从获取地形数据、确定滑体和滑床区域、建立滑体和滑床几何模型、生成颗粒模型四个步骤出发,提出基于数字等高线地形图建立PFC二、三维复杂滑坡模型的前处理方法,为今后基于PFC的滑坡运动过程模拟提供帮助。(2)采用PFC单轴压缩模拟试验对岩体力学细观参数进行标定,通过单因子变量法开展平行粘结模型下细观参数对试样的弹性模量、抗压强度和泊松比三个宏观特性影响的定性与定量分析,分析结果便于快速开展单轴压缩模拟试验并确定PFC模拟滑坡所需的材料细观参数。(3)分别建立红石岩滑坡的PFC~(2D)和PFC~(3D)模型,施加地震荷载,对其运动过程进行模拟,较好地反演了红石岩地震滑坡的运动过程和堆积特征,同时监测滑体颗粒的速度和位移,颗粒最大运动速度为48.9m/s,表明红石岩滑坡属于高速岩质滑坡,二、三维模拟得到堆积体形态相近,呈现前缘层状堆积,后缘混杂堆积的特点。(4)通过二、三维模拟对比分析,二维模拟滑坡总历时较短为60s,三维模拟中颗粒随机碰撞较多,导致颗粒速度较小,能量耗散更明显,堆积体混杂程度更高,虽然二维模拟有计算速度快的优势,但是三维模拟更能反映滑坡的运动路径、堆积范围、堆积厚度等,模拟效果更好。
[Abstract]:On Aug. 3, 2014, a magnitude 6.5 earthquake occurred in Ludian County, Zhaotong City, Yunnan Province, causing the collapse of the right bank near the Niulan Jiang Hongshi Rock Village, blocking the Niulan River, forming a barrier lake, and flooding the first part of the upstream Hongshiyan Hydropower Station. In this paper, based on the discrete element particle flow software PFC, the motion process of the Hongshi rock earthquake landslide is simulated, and the starting mechanism, motion path, velocity and accumulation range of the landslide are analyzed and discussed. The main work contents and results are as follows: (1) aiming at the problem of weak pre-treatment in the establishment of landslide model by PFC, taking the red rock landslide triggered by the 2014 earthquake as an example, taking the Brick filling method as the basis to obtain the topographic data, the sliding body and sliding bed area are determined. The geometric model of sliding body and sliding bed is established, and the particle model is generated. The pre-processing method of PFC 2 and 3 D complex landslide model based on digital contour topographic map is proposed. To provide help for the simulation of landslide motion process based on PFC in the future. The PFC uniaxial compression simulation test is used to calibrate the meso-parameters of rock mass mechanics, and the elastic modulus of the specimen under the parallel bond model is carried out by the single factor variable method. The qualitative and quantitative analysis of the influence of three macroscopic characteristics of compressive strength and Poisson's ratio, the analysis results are convenient for the rapid development of uniaxial compression simulation test and the determination of material mesoscale parameters required by PFC to simulate landslide. By applying seismic load and simulating its motion process, the movement process and accumulation characteristics of Hongshi rock earthquake landslide are well inversed, and the velocity and displacement of sliding particles are monitored at the same time. The maximum movement velocity of particles is 48.9 m / s, which indicates that the Hongshi landslide belongs to high speed rock landslide. Second, 3D simulation shows that the accumulation body is similar in shape, showing the characteristics of front edge stratiform accumulation and posterior edge mixed accumulation. The total duration of 2D simulated landslide is shorter than 60 s. In 3D simulation, there are more random collisions of particles, which results in smaller particle velocity, more obvious energy dissipation, and higher mixing degree of accumulative bodies, although 2D simulation has the advantage of fast calculation speed. But 3D simulation can better reflect the movement path, accumulation range and thickness of landslide.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P642.22

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