槐场村小后沟泥石流危险性评价

发布时间：2018-03-07 10:05

本文选题：泥石流　切入点：危险性评价　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：小后沟流域历史上虽未曾有过泥石流灾害记录,但由于其纵坡降较大且具备丰富的物源条件而成为潜在的泥石流地质灾害点,若满足强降雨条件,泥石流发展后冲出的堆积物将威胁沟谷南侧学校建筑及人身的安全。本文从定性分析与定量分析的角度出发,阐述了研究区泥石流流域的发育特征及发展规律,运用数值模拟的方法,以可视化、量化的方式揭露了研究区潜在的泥石流运动及堆积特征,并对该区泥石流潜在的危险性做了分析评价,对于本次研究而言,具有一定的预测意义:研究区满足具备发生泥石流的地形地貌条件及物源条件,并且整体泥石流流域状态仍呈不断发育的上升趋势,当具备一定降雨条件时,易引发泥石流灾害;在定量分析研究中,运用了二维洪水数值模拟演算程序FLO-2D,该程序是基于粘性-塑性-碰撞的流变模型,并采用中央有限差分的数值算法进行求解,在ARCGIS程序中建立栅格化的研究区数字高程模型,并于FLO-2D程序中通过划分边界、剖分网格、选取集水点、绘制流量过程曲线、选取初始参数从而进行模拟计算。本次研究模拟了爆发时间为60分钟,频率为20年一遇的泥石流成灾过程。模拟结果包括泥石流流速分布、堆积深度以及堆积范围。根据模拟结果显示,流速分布主要集中在1.2-1.6m/s范围,最大流速2.16m/s,堆积区形成堆积扇,泥石流过程最大泥深14.97m,最大堆积高度13.36m,堆积扇面积1625.3m~3,堆积物总体积2115.5m~3,该结果对比经验公式法所得到的一次泥石流固体冲出物的计算结果2678m~3误差为21%。根据以上分析结果,将数值模拟结果导入ARCGIS中进行进一步分析计算,以泥深与流速和泥深的乘积为两项评价指标,通过条件筛选,划定了泥石流的影响强度范围,综合爆发频率,进一步得到了泥石流灾害的危险区范围。当泥石流重现周期为20年一遇时,槐场村小学主教学楼恰好处在高危险区中,一旦爆发泥石流灾害,存在建筑物被迅速摧毁的可能性,需及时采取预防措施,如修建拦挡坝、栽植苗木、排水渠清淤等。
[Abstract]:Although there has been no record of debris flow disaster in the history of Xiaohou valley, it has become a potential geological hazard point of debris flow because of its large longitudinal slope decline and abundant source conditions, if the condition of heavy rainfall is satisfied. The accumulation of debris flow will threaten the safety of school buildings and people in the south side of the gully. From the angle of qualitative analysis and quantitative analysis, this paper expounds the development characteristics and development law of debris flow basin in the study area. Using the method of numerical simulation, the potential debris flow movement and accumulation characteristics in the study area are revealed in a visual and quantitative way, and the potential risk of debris flow in this area is analyzed and evaluated. It has certain prediction significance: the study area satisfies the landform and geomorphological condition and the material source condition of debris flow, and the state of the whole debris flow basin is still on the rise, when there are certain rainfall conditions, In the quantitative analysis, the two-dimensional flood numerical simulation program FLO-2D is used, which is based on the rheological model of viscous plastic collision and solved by the central finite difference numerical algorithm. The digital elevation model of rasterized research area is established in ARCGIS program. In FLO-2D program, the flow process curve is drawn by dividing the boundary, dividing the grid, selecting the water collecting point, and drawing the flow process curve. The initial parameters are selected to simulate the debris flow in 60 minutes and the frequency is once in 20 years. The simulation results include the velocity distribution of debris flow. The results of the simulation show that the velocity distribution is mainly in the range of 1.2-1.6 m / s, and the maximum velocity is 2.16 m / s, and the stacking zone forms the stacking fan. In the process of debris flow, the maximum mud depth is 14.97 m, the maximum accumulation height is 13.36 m, the accumulative fan area is 1625.3 m ~ (-3), and the total volume of deposit is 2115.5 m ~ (3). The calculated result of this result compared with the empirical formula method is 2678 m ~ (3) error is 21. The numerical simulation results are introduced into ARCGIS for further analysis and calculation. Taking the product of mud depth, velocity and depth of mud as two evaluation indexes, the influence range of debris flow intensity and the comprehensive burst frequency are determined by screening conditions. When the recurrence cycle of debris flow is once in 20 years, the main teaching building of primary school in Huichang Village happens to be in a high risk area. Once the debris flow disaster breaks out, there is the possibility that buildings will be destroyed quickly. Preventive measures should be taken in time, such as construction of blocking dam, planting of seedlings and dredging of drains, etc.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P642.23

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