山区沿河公路路基缺口机制研究

发布时间：2019-04-16 19:22

【摘要】：西南地区地质条件复杂，为水毁形成的重要区域。本文对西南地区公路水毁进行野外调研，根据西南地区水毁情况对公路水毁分类，分类包括路基缺口、堆积物掩埋道路、混凝土路面板悬空、路基沉陷、滑坡推挤路基、桥涵结构水毁等6类。将其中一种分类情况—路基缺口作为本文的研究对象，研究路基有护坡无面板，受山洪及泥石流作用下路基缺口的力学形成机制。分析其机制能掌握野外路基缺口的形成模式，掌握路基缺口的形成部位，发展过程，雨期缺口的形成时间，对安全避灾等能起到指导作用，并能针对路基缺口形成部位采取边坡防护、改善路基材料提高路基强度等措施增加路基缺口的形成周期。本文的主要工作：（1）对西南地区20余条国省道公路水毁情况进行了现场调研，主要进行省道公路水毁现场调查与资料收集，，对西南地区公路水毁情况进行了分析，以此对水毁作了科学的分类。（2）根据现场收集的沿线地形地貌、水文地质、岩性、地质构造、公路建筑特征等资料，分析了路基缺口形成的条件。（3）针对西南地区出现的路基缺口情况，分析了路基缺口的形成特点、力学破坏模式，并针对不同破坏模式分析了其形成过程以及形成机理。（4）基于流体力学方法，确定了弯道环流作用下的掏蚀槽球心深度位置，以及水平环流作用下的掏蚀槽底面圆心的平面位置，根据运动学以及Osman公式得到了掏蚀槽半径随时间变化的理论公式。（5）基于弹塑性力学方法，分析了路基缺口的三维力学模型—滑动失稳型缺口的启动机制，根据极限平衡理论，求解了此类缺口的临界掏蚀槽半径公式，分析了以掏蚀槽半径为判定条件的缺口形成机制。（6）基于弹塑性力学方法，分析了路基缺口的三维力学模型—坠落失稳型缺口的起动机制，根据极限平衡理论，求解了此类缺口的临界掏蚀槽半径公式，分析了以掏蚀槽半径为判定条件的缺口形成机制。（7）基于塑性力学方法，分析了路基缺口的三维力学模型—泥石流冲击型缺口的启动机制，分析了泥石流浆体冲击力大小与缺口形态的关系，并建立了泥石流冲击力与路基顶面冲击方向上缺口长度之间的关系式；根据塑性力学和hertz碰撞理论求解了泥石流中大块石的冲击力与冲击坑半径的关系式。
[Abstract]:The geological conditions in southwest China are complex, which is an important area in the formation of water damage. This paper makes a field investigation on highway water damage in southwest China, classifies it according to the water damage situation in southwest China, including roadbed gap, accumulation buried road, concrete pavement slab hanging, roadbed subsidence and landslide pushing roadbed. There are 6 kinds of bridge and culvert structures, such as water damage and so on. Taking the roadbed gap as the research object, this paper studies the mechanics formation mechanism of roadbed notches under the action of mountain flood and debris flow. The analysis of its mechanism can master the formation mode of roadbed gap in the field, the forming position of roadbed gap, the development process, and the forming time of the gap in rainy period, which can play a guiding role in safe avoiding disaster and so on. It can increase the period of roadbed notch formation by taking measures such as slope protection, improving roadbed material and improving subgrade strength, aiming at the formation position of roadbed notch. The main work of this paper is as follows: (1) the situation of water damage of more than 20 national provincial highways in southwest China is investigated on the spot, mainly on the spot investigation and data collection of provincial highway water damage, and the situation of highway water damage in southwest China is analyzed. A scientific classification of water destruction was made. (2) according to the data of landform, hydrogeology, lithology, geological structure and highway construction, the conditions of the formation of roadbed gap are analyzed. (3) in view of the roadbed gap in southwest China, the formation characteristics and mechanical failure mode of roadbed gap are analyzed, and the formation process and formation mechanism of roadbed notch are analyzed according to different failure modes. (4) based on the hydrodynamics method, the depth position of the spherical center of the grooves under the action of the curved circulation and the plane position of the center of the bottom surface of the grooves under the action of the horizontal circulation are determined. According to the kinematics and the Osman formula, the theoretical formula of the time-dependent variation of the grooving radius is obtained. (5) based on the elasto-plastic mechanics method, the starting mechanism of sliding unstable notch, a three-dimensional mechanical model of roadbed notch, is analyzed. According to the limit equilibrium theory, the critical notch radius formula of this kind of notch is solved. The mechanism of notch formation based on the cutting groove radius is analyzed. (6) based on elasto-plastic mechanics method, the three-dimensional mechanical model of roadbed notch, the starting mechanism of falling unstable notch, is analyzed. According to the limit equilibrium theory, the critical notch radius formula of this kind of notch is solved. The mechanism of notch formation based on the cutting groove radius is analyzed. (7) based on the plastic mechanics method, the three-dimensional mechanical model of roadbed notch-the initiation mechanism of debris flow impact notch is analyzed, and the relationship between the impact force of debris flow slurry and the notch shape is analyzed. The relationship between the impact force of debris flow and the notch length in the direction of impact on the top of roadbed is established. According to plasticity mechanics and hertz collision theory, the relation between the impact force and the radius of impact pit in debris flow is solved.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U416.1

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