泥石流大块石对桥梁的冲击危害
文献类型：学位论文
| 作者 | 林伟 |
| 学位类别 | 硕士 |
| 答辩日期 | 2012-06 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 谢洪 ; 马东涛 |
| 关键词 | 泥石流 大块石 桥梁 危害 |
| 其他题名 | Damage of Boulders in the Debris-flow Impacting on the Bridge Pier |
| 学位专业 | 岩土工程 |
| 中文摘要 | 泥石流暴发常常会破坏工程建筑，尤其是泥石流中的大块石对横跨沟道的桥梁危害巨大。因此研究泥石流中大块石的冲击破坏能力并进行相应防范，减轻其破坏作用，很有必要。本研究采用比较分析前人的研究成果和对泥石流中大块石对桥墩的冲击进行数值模拟的方法，对泥石流中大块石冲击桥墩的危害进行了探讨，并得出了以下的研究成果。 1、通过比较分析总结出了计算泥石流中大块石的冲击力所需参数：大块石的粒径可以采用经验公式和实地调查结果两者的较大值；大块石的撞击位置则采用大块石半径与泥深的较大值。 2、根据数值模拟分析发现，模拟的冲击力结果与抗弯刚度法计算公式计算结果存在一个很好的比例关系：当桥墩为简支梁时这一比例为0.055，而桥墩为悬臂梁时比例为0.086。并且模拟出的冲击力大小与公式计算出的冲击力大小存在二次关系。 3、数值模拟分析还发现桥墩采用不同结构时，它们的抗剪强度是不一样的：当桥墩采用简支梁时，在大块石以7 m/s的速度冲击混凝土柱时，混凝土柱被拦腰剪断，此时的冲击力为17.6×106 N；当桥墩为悬臂梁时，大块石速度为4 m/s时，就能剪断混凝土柱，此时的冲击力为11.3×106N。 4、模拟结果显示采用不同结构时，桥墩被冲击破坏的方式也不同：当桥墩简化为简支梁时，泥石流大块石对桥墩的破坏是一个渐进的过程，从局部的破坏到中部被剪断到桥段被彻底破坏；当桥墩简化为悬臂梁时，大块石的冲击速度较小时只会导致桥墩的撞击位置处被破坏，当冲击力达到一定程度时，则直接剪断桥墩的脚尖处部分，而桥墩的背部脚尖处会受到挤压破坏。 5、以在建的成兰铁路太平沟为例，利用研究成果并结合实际情况提出了防治太平沟泥石流大块石对叠溪车站桥梁的冲击破坏措施。加固桥梁和减小桥墩的刚性是一种非常有效的主动防御措施。同样，采用拦护排的综合措施可以很好地减轻泥石流对桥梁的危害。 |
| 英文摘要 | The debris flow often wash out the engineering construction and bring personal and property losses to the local residents. Among the damages，boulders in the debris flow pose a grave threat to the bridge across the debris flow channel. Therefore，comparative analysis of previous research results and numerical simulation were conducted to study the damage of the impact of boulder in the debris flow on bridge piers. Some research results are follows： 1.Summed up the required counting parameters for impact of boulder in the debris flow through the comparative analysis： The size of boulder can adopt the higher value of the empirical formula and field survey results，and the impact location of the boulder using a larger value of the radius of the boulder and level mud. 2.According to the numerical simulation，there is a certain proportional relationship between the results from the numerical simulation and the calculated results from the Flexural Stiffness Method： Pier for simply beam ，the ratio was 0.055 ，while the pier as a cantilever beam the ratio was 0.086 .And the impact from the numerical simulation and Flexural Stiffness Method exists a quadratic relationship. 3.Simultaneously，it is found that shear strength varies with structures： When pier is simplified as simply beam ，the boulder impacts on the concrete column and can cut down it at the speed of 7 m/s ，the impact force is 17.6 × 106 N ；when the pier for the cantilever ，the boulder can cut down the concrete columns at the speed of 4 m/s and the impact force is 11.3 × 106 N . 4. Failure modes are different with different structures： The destruction of the boulder in the debris flow impacting on the piers when the pier as a simply beam is a gradual process： The first is the partial destruction ，and then pier was cut ，and finally the pier was completely destroyed； While piers as a cantilever beam，the failure mode is different： when the velocity of the boulder is small，the boulder only can lead the impact location to be destroyed. When the impact force reaches a certain level，the boulder can directly cut the toe part of the pier，and the back toe of the pier is squeezed destruction. 5.Finally，taking the Tai-ping gully as the example，some effective measures of prevention of the boulders in the debris flow impact on the Die-xi station bridge are proposed according to the research results and combining with the actual destruction of this gully. Reinforce bridges piers and reduce the piers' strength are also some very effective active measures .Similarly，the comprehensive measure of check dams，drainage canals and fender piers will mitigate the damage of debris flow on the bridge effectively. |
| 学科主题 | 岩土力学 ; 灾害学 |
| 语种 | 中文 |
| 公开日期 | 2012-07-29 |
| 源URL | [http://192.168.143.20:8080/handle/131551/4178]  |
| 专题 | 成都山地灾害与环境研究所_山地灾害与地表过程重点实验室 |
| 推荐引用方式 GB/T 7714 | 林伟. 泥石流大块石对桥梁的冲击危害[D]. 北京. 中国科学院研究生院. 2012. |
入库方式： OAI收割
来源：成都山地灾害与环境研究所
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