吴堡井沟泥石流基本特征及其动力学数值模拟分析

发布时间：2018-04-14 23:26

本文选题：井沟泥石流 + 基本特征　；参考：《西安科技大学》2017年硕士论文

【摘要】：城镇建设中泥石流危害正在引起公众、媒体和工程地质界的重视。对基本特征及动力学特征机理的探索,具有重要的理论意义及现实价值。以陕西省吴堡县宋家川镇井沟泥石流为研究对象,基于实际勘查数据,借助于数学、力学、计算机等理论与技术,进行泥石流运动过程中状态、接触力、速度及位移情况研究,得到三点结论:(1)分析得到井沟泥石流的主要特征:①吴堡县井沟泥石流活动微弱,发生频率低较,规模大,暴发频率约十年一次。②流域平面形态呈长条树枝形,泥石流的三区各具特征:形成区“大而缓”,流通区“短且窄”、堆积区“平而广”。③综合分析得到井沟泥石流重度14.5kN/m3;流速1.19-4.28m/s;流量5.6m3/s-20.61m3/s;一次最大冲出量0.4×104m3-1.5×104m3;一次泥石流冲出固体物质总量0.17×104m3-6.4×104m3;单块巨石的撞击力为22.4kPa-80.5kPa;整体冲击压力11.9kPa-42.8kPa;最大冲起高度为0.31m-1.11m;爬高 0.49m-1.78m,弯道超高 0.43m-1.53m。(2)分析了井沟泥石流形成机制:初期以重力侵蚀作用为主、中后期以水力侵蚀作用为主。在降雨的条件下,弃渣坝体逐步达到饱和状态,在自身重力作用下,水和固体物质发生运动,二者汇流后形成初期泥石流。随着暴雨的持续,弃渣坝残留的固体物质及沟床内固体物质持续受水动力的片蚀和侵蚀,使固体物质不断参与泥石流,同时沟道两侧谷坡上的不稳定物源也受暴雨冲刷等方式失稳进入沟道,加剧泥石流的规模。(3)利用颗粒流(PFC2D)数值模拟分析井沟泥石流动力学特征。结合泥石流流域、动力特征,对井沟泥石流运动过程进行模拟,再现井沟泥石流运动状态、接触力、速度及位移。分析颗粒冲出最大速度、位移曲线图。根据实际情况预测,井沟泥石流的最大冲淤距离可达2693m,到达吴堡县城幼儿园附近。
[Abstract]:Debris flow hazards in urban construction are attracting the attention of the public, media and engineering geology.It is of great theoretical significance and practical value to explore the basic characteristics and the mechanism of dynamic characteristics.Taking the well gully debris flow in Songjiaguan Town, Wubao County, Shaanxi Province as the research object, based on the actual exploration data and with the help of mathematics, mechanics, computer and other theories and techniques, the state, contact force, velocity and displacement of debris flow in the course of the debris flow movement are studied.The main characteristics of mud-rock flow in Wubao county, Wubao county, were analyzed. The debris flow activity was weak, the frequency of debris flow was lower and the scale was large. The outbreak frequency was about once in ten years, and the plane shape of the basin was in the shape of long branches.Each of the three zones of debris flow has its own characteristics: the forming area is "large and slow", and the circulation area is "short and narrow".The comprehensive analysis of "flat and wide" .3 shows that the debris flow in the well gully is 14.5 KN / m3; the velocity is 1.19-4.28 m / s; the flow rate is 5.6 m3 / s; the maximum flow volume is 0.4 脳 104m3-1.5 脳 104m3; the total amount of solid material washed out by a debris flow is 0.17 脳 104m3-6.4 脳 104m3; the impact force of a monolithic boulder is 22.4kPa-80.5 kPa; the whole impact pressure is 11.9kPa-42.8kPa.The formation mechanism of mud-rock flow in the well gully is analyzed: gravity erosion is the main action in the initial stage, and the height is 0.31m-1.11m; the climbing height is 0.49m-1.78m; and the bend is ultra-high 0.43m-1.53m.In the middle and late stage, hydraulic erosion is the main action.Under the condition of rainfall, the abandoned slag dam body gradually reaches saturation state. Under the action of its own gravity, the water and solid matter move, and the debris flow is formed in the initial stage after the confluence of the two bodies.With the continuous torrential rain, the residual solid matter in the abandoned slag dam and the solid material in the ditch bed are continuously eroded and eroded by the hydrodynamic force, which makes the solid material participate in the debris flow continuously.At the same time, the unstable material source on the valley slope on both sides of the channel is also unstable into the channel by torrential rain, which intensifies the scale of debris flow, and uses particle flow PFC2D) to simulate and analyze the dynamic characteristics of well gully debris flow.Combined with the dynamic characteristics of debris flow basin, the movement process of well gully debris flow is simulated, and the movement state, contact force, velocity and displacement of well ditch debris flow are reproduced.The maximum velocity and displacement curve of particles are analyzed.According to the actual situation, the maximum erosion and siltation distance of mud-rock flow can reach 2693 m and reach near the kindergarten of Wubao county.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P642.23

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