土木工程防灾减灾概论大论文.doc

摘 要 泥石流是由于降水(暴雨、融雪)而形成的一种挟带大量泥砂、石块等固体物质的固液两相流体，呈黏性层流或稀性紊流等运动状态，是高浓度固体和液体的混合颗粒流。典型的泥石流由悬浮着粗大固体碎屑物并富含粉砂及黏土的黏稠泥浆组成。在适当的地形条件下，大量的水体浸透山坡或沟床中的固体堆积物质，使其稳定性降低，饱含水分的固体堆积物质在自身重力作用下发生运动，就形成了泥石流。其暴发突然、历时短暂、来势凶猛，具有极强的破坏力，是一种灾害性的地质现象。泥石流的主要危害是冲毁城镇、矿山、乡村，造成人畜伤亡，破坏房屋及其他工程设施，破坏农作物、林木及耕地。此外，泥石流有时也会淤塞河道，不但阻断航运，还可能引起水灾。影响泥石流强度的因素较多，如泥石流容量、流速、流量等，其中泥石流流量对泥石流成灾程度的影响最为主要。此外，多种人为活动也在多方面加剧这上述因素的作用，促进泥石流的形成。本次论文主题就是泥石流，以舟曲特大泥石流为例子进行有关的分析与阐述。 关键词：泥石流，降水,泥沙,灾害，流体，地质 ABSTRACT Debris flow is due to the precipitation (rain and snow melt) formed by a flood of solid material such as clay sand, stones of solid-liquid two-phase fluid, a viscous laminar or dilute turbulent motion, such as is the flow of high concentrations of the mixture of solid and liquid particles. Typical debris flow by the float bulky solid debris and rich silt and clay sticky mud. In the appropriate terrain conditions, a large amount of water to soak the slopes or solid accumulation of gully bed material, make its stability is reduced, the hydrated solid packing material movement, under their own gravity has formed mudslides. Its outbreak suddenly, briefly, aggressive, with a strong destructive power, is a severe geological phenomenon. Landslides are the main hazards of destroyed town, mines, rural, human and animal casualties, destruction of houses and other engineering facilities, damage crops, forests and farmland. In addition, the debris flow sometimes siltation of river channel, not only block the shipping, may cause floods. Factors that affect debris flow intensity is more, such as debris flow capacity, flow velocity, flow, the debris flow influence on the degree of debris flow by most major. In addition, a variety of human activities has contributed in many aspects that the role of the above factors, promote the formation of debris flow. This thesis is the debris flow, with heavy zhouqu mudslide as example to analysis and elaboration. Key words: Mu