汶川震区泥石流冲出规模的预测评价

发布时间：2018-04-18 09:27

  本文选题：震区 + 泥石流　； 参考：《成都理工大学》2015年硕士论文

【摘要】：研究区位于“5·12”地震重灾区,震后急速增长的物源和震区陡峭的有利地形条件使得汶川地区新增1000余条沟谷泥石流。震后震区经历的6个雨季中,每年都暴发了大规模的泥石流灾害,以2010年龙池和映秀的“8·13”泥石流和2013年汶川的“7·10”泥石流尤为严重。2010年8月13日,汶川映秀-威州、龙池、清平三地共有85条沟谷暴发泥石流,冲出规模达1501×104m3,单沟以文家沟450×104 m3冲出规模最大;2013年“7·10”降雨激发岷江两岸100多条沟谷暴发泥石流,冲出规模为1000×104 m3,单沟以七盘沟冲出规模(约80×104 m3)最大,危害最为严重。冲出规模增大是震后震区泥石流的主要运动特征,这些大规模的泥石流淹没房屋,工厂,摧毁道路,堵断河流,破坏着灾区的重建成果,严重影响着下游地区人民的生命财产安全。由此看来,受到地震的影响,震区泥石流发生的频率与规模,势必将有愈来愈严重的趋势。因此针对震区泥石流的冲出规模进行研究,构建科学合理的泥石流冲出规模评估模型,对灾区土地规划、灾情评价、灾害的预警、防治以及工程效益评价十分重要的参考价值。本文主要从建立预测模型和数值分析两个方面开展震区泥石流冲出规模的研究。本文的研究区集中分布在汶川岷江沿线映秀-威州段、龙池龙溪河流域和清平绵远河沿岸,共计27条泥石流沟。其中,汶川震区7条,龙池地区11条,清平片区9条泥石流沟,选定流域面积(A)、相对高差(H)、沟道纵坡降(J)以及流域内滑坡面积(AL)等四大影响因素作为冲出规模(V)的评估指标,探讨泥石流冲出规模的预测模型。通过应用回归分析泥石流冲出规模与流域面积(A)、相对高差(H)、沟道纵坡降(J)以及流域内滑坡面积(AL)的相关性可知,各因素与冲出规模的相关性为滑坡物源面积流域面积流域相对高差沟道纵比降,且前三项与冲出规模的相关系数均大于0.85,属高度相关,故选定前三项为冲出规模的影响因子,并建立数学模型V=14.3698A0.2456AL0.2732H0.2798。通过其它地区泥石流相关参数验证可知该模型具有较好的适用性。期望未来评估泥石流灾害问题时,该模型能快速量度泥石流冲出规模,为相关泥石流的危险性评价提供参考依据。为了解泥石流发生的运动形态,预测成灾范围和规模能够更加直观的表达出来,本研究利用O’Brien and Julian于1988年发表的FLO-2D二维洪灾模式进行二维泥石流灾害模拟。配合网格化的数值地形模型,将加入流变方程式后的洪灾模式转换为可模拟泥石流流变行为的分析模式。研究区主要以汶川震区码头沟和羊岭沟两个典型泥石流沟作为研究对象,并分别使用2010年“8·13”和2013年“7·10”的降雨量为依据,探讨泥石流的最大堆积深度、堆积范围,进而估算出泥石流的冲出规模。本文分别模拟两条泥石流沟在自然条件和发生溃决两种情况下的冲出规模,码头沟和羊岭沟在自然条件下四种降雨频率(P=1%,P=2%,P=5%,P=10%)的冲出规模,码头沟各频率下冲出规模为1%(15.8×104m3)、2%(10.18×104 m3)、5%(7.08×104 m3)、10%(4.42×104 m3);羊岭沟四种降雨频率下冲出规模分别为为1%(12.83×104 m3)、2%(8.59×104 m3)、5%(6.08×104 m3)、10%(4.50×104m3)。结果表明随降雨频率的减小,重现周期的增大,泥石流的冲出规模不断增大;且堆积扇面积和堆积深度也随降雨频率的增大而减小。码头沟暴发溃决泥石流时,泥石流冲出规模为23.06×104 m3,与自然条件下相比冲出规模增大了1.26倍,冲出范围增大到1.20倍;羊岭沟暴发溃决泥石流时,冲出规模是自然条件下的1.76倍,堆积范围将增大到1.65倍。本文从数学计算模型和FLO-2D数值模拟两个方面研究冲出规模,相对而言,前者能快速计算出泥石流的冲出规模,FLO-2D数值模拟则更加直观的表现出泥石流的冲出范围、堆积扇的堆积形态和堆积厚度,但须耗费大量时间。综合两种研究方法的特点,在进行泥石流研究时,尤其对区域分布密集的区域性泥石流进行危险性评价时,可以先通过预测模型计算的冲出规模大小判断出高危险度的泥石流沟,然后再利用FLO-2D二维数值模拟软件对其进行模拟计算,得出泥石流冲出规模的堆积形态、堆积范围、堆积深度等等。
[Abstract]:The study area is located in the "5 - 12" the hardest hit by the earthquake, after the earthquake, the rapid growth of the earthquake source and steep favorable terrain conditions make Wenchuan area more than 1000 new Valley debris flow. 6 earthquake earthquake experience in the rainy season, every year a large outbreak of debris flow disaster in 2010, dragon pool and Yingxiu "8. 13" and "7 debris flow in Wenchuan in 2013 10 the debris flow is particularly serious in August 13th.2010, Wenchuan Yingxiu Qingping Wei Zhou, dragon pool, three a total of 85 debris flow gullies, out of the size of 1501 * 104m3, the single channel in Wenjiagou 450 * 104 m3 out of the largest scale in 2013;" 7. 10 "Minjiang Valley on both sides of the more than 100 rainfall triggered debris flow, out of the size of 1000 * 104 m3, the single channel in seven sets out the scale of ditch (about 80 x 104 m3), the most serious hazards. Out of scale is the main characteristics of post earthquake debris flow movement, these. Die buried houses, factories, destroyed roads, blocked rivers, destroying the disaster reconstruction results, seriously affect the downstream region of the people's lives and property. Therefore, affected by the earthquake, earthquake frequency and scale of debris flow, there will be more and more serious trend. So for the earthquake debris flow out of the scale of construction of scientific and reasonable scale of debris out of the disaster disaster assessment model, land planning, evaluation, disaster warning, prevention and evaluation of project benefit reference value is very important. This article mainly from the establishment of prediction model and numerical analysis of the two aspects to carry out earthquake debris out scale research. The study area of concentration located in Wenchuan Minjiang River along Yingxiu Westphalia, long long Chi River Basin and Qingping Mianyuan River, a total of 27 debris flow gullies. Among them, 7 Wenchuan earthquake, dragon pool Area 11, Qingping area 9 debris flow gullies, selected catchment area (A), the relative elevation (H), channel longitudinal (J) and the basin landslide area (AL) and other four factors influence as out of scale (V) assessment indicators, to explore the prediction model of debris out of scale. Through analysis of debris out scale and watershed area regression (A), the relative elevation (H), channel longitudinal (J) and the basin landslide area (AL) between the various factors and out of scale between the source area of landslide drainage area of gully basin relative elevation gradient, and the correlation coefficient the first three items and out of scale are greater than 0.85, is highly related, the former three are selected out of scale factors, and establish the mathematical model of V=14.3698A0.2456AL0.2732H0.2798. by other areas of debris flow related parameters verification shows that the model has good applicability. Not expected To evaluate the debris flow problem, this model can quickly measure the size of debris out, provide a reference basis for the risk assessment of debris flow. In order to understand the related movement patterns of the occurrence of debris flow disaster prediction scope and scale to be able to be expressed more intuitive, the study adopted O Brien and Julian published in 1988 FLO-2D 2D model of flood disaster the two-dimensional debris flow simulation. Combined with digital terrain model grid, will join the flood mode conversion after the rheological equation analysis model can simulate the rheological behavior of debris flow. The study area mainly in the Wenchuan earthquake and the pier ditch Yang Ling ditch two typical debris flow as the research object, and use "8 - 13" in 2010 and 2013 "7 - 10" rainfall as the basis, the maximum depth of debris flow accumulation, accumulation, and estimate the size of the debris flow out. 鍒嗗埆妯℃嫙涓ゆ潯娉ョ煶娴佹矡鍦ㄨ嚜鐒舵潯浠跺拰鍙戠敓婧冨喅涓ょ�嶆儏鍐典笅鐨勫啿鍑鸿�勬ā,鐮佸ご娌熷拰缇婂箔娌熷湪鑷�鐒舵潯浠朵笅鍥涚�嶉檷闆ㄩ�戠帲�

本文编号：1767777