滑体运动及其对受灾体和挡墙冲击作用的离散元模拟

发布时间：2018-03-26 18:26

本文选题：滑体颗粒　切入点：运动特性　出处：《兰州大学》2015年硕士论文

【摘要】：滑体运动包含滑体崩落、滑动、滚动、坡面撞击回弹以及滑体颗粒之间相互碰撞等多种作用形式,运动过程与滑体颗粒的力学特性、物理参数以及边坡特性等多种因素有关。目前,相关研究大多是基于滑体的形成机理,而对其滑后运动特性的研究相对较少。因此,本论文基于离散单元法对滑体下滑的运动进行仿真,着重对滑体在流向内物体前的堆积特性及其对挡墙所造成的冲击作用等进行分析。主要研究工作如下：首先,建立了滑体运动及其对流向内受灾体冲击的二维离散单元模型。基于滑体下滑过程中不同时刻的空间形态,分析了其下滑过程中的基本运动特性。同时,通过统计滑体滑动过程中对流向内物体不同高度处的冲击作用,分析了滑体冲击结束后的静态堆积特性；最后分析了滑体颗粒间的摩擦系数、堆积区域长度以及边坡坡角对滑体下滑后的最大堆积力的影响规律,并进一步讨论了这些参数对滑体静态堆积形态的影响。其次,基于颗粒流理论,建立了一个简单的斜面滑体颗粒对挡墙的动态冲击模型。通过分析滑体在斜面滑动过程中的动力学行为及其能量耗散特征,给出滑体在整个冲击过程中对挡墙冲击作用的时空演化规律,得到的动态冲击力与已有实验结果定性一致。针对不同滑体颗粒的初始构型,讨论了最大动态冲击力的分布特征。在此基础上,分析了滑体颗粒摩擦系数、滑体的斜面滑动距离以及边坡坡面粗糙度等参数对挡墙所受最大冲击力的影响。总之,通过对滑体运动过程中的动力学特性及其对受灾体及挡墙的冲击作用研究,一方面可以为工程建设中边坡防护结构的设计建造提供相关理论支持。另一方面可以探究颗粒群体与连续结构之间的复杂作用过程,这对从微观层面研究滑体运动的动力学特性是一个有益的尝试。
[Abstract]:The motion of sliding body includes many kinds of action forms, such as caving, sliding, rolling, bumping and springback of slope, and collision between particles of sliding body, and so on, and the movement process and the mechanical properties of the particles of sliding body. Physical parameters and slope characteristics are related to many other factors. At present, most of the related studies are based on the formation mechanism of sliding body, but there are few researches on its motion after sliding. Based on the discrete element method, this paper simulates the sliding motion of sliding body, focusing on the analysis of the stacking characteristics of the sliding body before the flow direction of the body and its impact on the retaining wall. The main research work is as follows: first of all, A two-dimensional discrete element model of sliding body motion and its impact on the body affected by the flow direction is established. Based on the spatial morphology of the sliding body at different times, the basic motion characteristics of the sliding body are analyzed. The static stacking characteristics of the sliding body after the end of the impact are analyzed by statistics of the impact action of the sliding body on different heights of the body in the flow direction. Finally, the friction coefficient between the particles of the sliding body is analyzed. The influence of the length of the stacking region and the slope angle on the maximum stacking force of the sliding body is discussed, and the influence of these parameters on the static stacking shape of the sliding body is discussed. Secondly, based on the particle flow theory, In this paper, a simple dynamic impact model of inclined sliding body particles on retaining wall is established. The dynamic behavior and energy dissipation characteristics of sliding body during slope sliding are analyzed. The temporal and spatial evolution of the effect of sliding body on the impact of retaining wall during the whole impact process is given. The obtained dynamic impact force is qualitatively consistent with the existing experimental results. The distribution characteristics of maximum dynamic impact force are discussed. On the basis of this, the influence of parameters such as the friction coefficient of sliding particles, slope slip distance and slope roughness on the maximum impact force on the retaining wall is analyzed. The dynamic characteristics of the sliding body and its impact on the affected body and retaining wall are studied. On the one hand, it can provide theoretical support for the design and construction of slope protection structure in engineering construction, on the other hand, it can explore the complex process between particle group and continuous structure. This is a useful attempt to study the dynamic characteristics of sliding body motion from the micro level.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.2

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