岩体崩塌落石对桥梁破坏作用的动态演绎研究

发布时间：2018-05-19 14:47

本文选题：崩塌落石 + 链式演化　；参考：《重庆交通大学》2014年硕士论文

【摘要】：崩塌灾害问题一直困扰着边坡建设工程的稳定与发展，也是地质灾害中比较热门的研究课题之一。随着国内土建行业的快速发展，尤其是在西部地区，而西部多为山丘地带，平地资源有限，有很多建筑物都必须依山而建，再加之西部地区处在地震带区域，地震带来的地质灾害不同程度的威胁着已建的和在建的工程。崩塌是一种破坏性、随机性极大的地质灾害之一，国内几乎每年都有一个大型崩塌事故，造成严重的人员伤亡与经济损失。目前已有很多学者对落石冲击路基路面、隧道及铁路进行研究，，并取得了一定的成果，但在桥梁受落石冲击方面涉及较少。为了认识桥梁受落石冲击后的动力响应特点、桥梁破坏特点及薄弱部位，建立了落石与桥梁的三维模型，初步得出了桥梁在受落石冲击作用整个桥梁的动力特性。在此基础上结合研究了处于山区桥梁受崩塌落石威胁区域的防护系统布置原则，并引入灾变链式理论中的断链减灾方法，分析了传统防护技术的断链减灾思想。对桥梁自身加固，采取对桥墩增设防冲击垫层，来减小桥墩所受的冲击动能。通过研究分析，得到以下的结论：①针对岩石崩塌对崩塌落石的诱发因素重新认识，把崩塌控制因素分为内因与外因；对崩塌的演化机理进行分析，把岩石崩塌的链式效应划分为三个阶段，即孕育阶段、蠕变阶段、破坏阶段。②岩体崩塌落石的运动方式较多，常见的主要有落体、斜抛、平抛、滑移、滚动及上述运动的组合。影响落石运动轨迹的因素较多，概括起来主要有坡角、坡面植被情况、坡面岩性，落石的形状、大小、强度等。③在对桥梁受落石冲击的动力响应方面的初探，这是一个极为短暂的概念，用试验按照原比例还原十分困难，缩小比例则误差较大，所以借助软件来模拟计算。经过初步计算分析表明：当桥面板受落石冲击时候，整个冲击过程，对邻跨的内部应力及位移影响很小，落石冲击荷载的局部作用较为明显；当桥墩受冲击时，桥墩的可能因为屈曲失稳，而桥墩失稳会可能带来整个桥梁坍塌。④在防护方面借助已有对隧道、公路防落石撞击的技术措施，对山区桥梁所处的地理位置与崩塌体关系分析的基础上，初步给出了被动防护的布置原则，并对桥墩自身加固方面做了增设防护层的措施，并模拟计算验证了实施的可行性。
[Abstract]:The problem of collapse hazard has been perplexing the stability and development of slope construction engineering, and is also one of the hot research topics in geological disasters. With the rapid development of the civil engineering industry in China, especially in the western region, and the western region is mostly hilly, the flat land resources are limited, there are many buildings must be built according to the mountains, and the western region is located in the seismic zone area. Geological hazards caused by earthquakes threaten the existing and ongoing projects to varying degrees. Collapse is one of the most destructive and random geological disasters. There is almost a large avalanche in China every year. Collapse accident, causing serious casualties and economic losses. At present, many scholars have studied the impact of rock fall on subgrade and pavement, tunnel and railway, and achieved certain results, but there is little involved in the impact of rock fall on bridges. In order to understand the characteristics of dynamic response, damage characteristics and weak position of the bridge after falling stone, the 3D model of rock fall and bridge is established, and the dynamic characteristics of the bridge under the impact of falling stone are preliminarily obtained. On the basis of this, the principle of protection system arrangement in the area threatened by collapse and falling rock of bridges in mountainous area is studied, and the method of chain breaking disaster reduction in catastrophe chain theory is introduced, and the idea of chain breaking disaster reduction based on traditional protection technology is analyzed. Strengthen the bridge itself and take the bridge piers Add anti-shock cushion to reduce the impact kinetic energy of pier. Through the research and analysis, the following conclusions are drawn: 1 according to the new understanding of the inducing factors of rock collapse on the rock collapse, the controlling factors of collapse are divided into internal and external causes, and the evolution mechanism of collapse is analyzed. The chain effect of rock collapse is divided into three stages. That is to say, there are many movement modes of rock mass collapse and falling in gestation stage, creep stage and failure stage. The common ones are falling body, oblique throwing, flat throwing, sliding, rolling and the combination of above motion. There are many factors that affect the trajectory of stone falling, and the main factors are slope angle. The preliminary study of vegetation, lithology, shape, size and strength of the slope in the dynamic response of the bridge to the impact of the falling rock is a very brief concept, and it is very difficult to restore it in proportion to the original scale by the experiment. Reducing the proportion of the larger error, so with the help of software to simulate the calculation. The results of preliminary calculation and analysis show that the whole impact process has little effect on the internal stress and displacement of adjacent span, and the local effect of rockfall impact load is more obvious when the bridge deck is impacted by falling stone, and when the pier is impacted by the impact, the influence of the impact process on the internal stress and displacement of the adjacent span is very small. The bridge pier may be buckled and unstable, and the pier instability may lead to the collapse of the whole bridge. 4. In terms of protection, with the help of the existing technical measures to prevent the impact of the tunnel and the highway from falling stones, Based on the analysis of the relationship between the location of bridges in mountainous areas and the collapse body, the layout principles of passive protection are given, and the measures of adding protective layer to the reinforcement of piers themselves are made, and the feasibility of implementation is verified by simulation calculation.
【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】：P642.21;U445.7;U441

【参考文献】