基于数值模拟的震区溃决型泥石流入流点选取探讨
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摘要
FLO-2D模型假定下伏沟床固定,未考虑泥石流沿程侵蚀,但侵蚀作用带来的泥石流沿程补给是强震区泥石流的主要活动特性,在溃决型泥石流中侵蚀作用尤为强烈,忽略该侵蚀过程,将会造成流体规模的严重低估。本文选取汶川震区典型溃决型泥石流沟为研究对象,利用泥石流过程机制的分析,将沟床侵蚀结束的位置设置为入流点,即侵蚀/堆积的分界点。为确定溃决型泥石流入流点流量过程线,将沟道最后一级已溃决的堰塞体参数输入到BREACH模型中,获得与实际相吻合的溃口流量过程线,依据体积浓度划分清水流量过程线在入流点处输入进行模拟研究。引入同时考虑淤积范围与堆积方量的精度评估模型,结合实际暴发情况对模拟结果进行评估,结果表明基于FLO-2D的震区溃决型泥石流数值模拟可将入流点设置在侵蚀与堆积分界点处,为该模型在强震区溃决型泥石流冲出规模预测的应用上提供一定的科学依据。
The FLO-2 D model assumes that the underlying bed of the channel is fixed with no consideration of the erosion of the debris flow,but the supply from the debris flow erosion is the main feature of the debris flow activity in the co-seismal area. The erosion of dam-break debris flow is particularly strong and ignoring this will cause a serious underestimation of the run-out scale. To verify this hypothesis,this study selected the typical debris flow events in the earthquake area and set the inflow point,the boundary point of erosion and accumulation,at the end bed of the channel erosion according to the process mechanism of debris flow. At the same time,in order to determine the flow curve of the break debris flow,parameters of dam around channel outlets were input to the Breach model to obtain the simulation flow curve that matched the actual flow,the simulation was carried out by inputting the flow curve with the consideration of the volume concentration in the inflow point. The simulation results were compared with the actual situations of outbreak using the precision evaluation model,the results showed that the inflow point on the boundary of accumulation and erosion was suitable for the outburst debris flow,which can provide scientific reference for the accuracy and feasibility of applying the FLO-2 D model in the runout scale prediction of the dam-break debris flow.
The FLO-2 D model assumes that the underlying bed of the channel is fixed with no consideration of the erosion of the debris flow,but the supply from the debris flow erosion is the main feature of the debris flow activity in the co-seismal area. The erosion of dam-break debris flow is particularly strong and ignoring this will cause a serious underestimation of the run-out scale. To verify this hypothesis,this study selected the typical debris flow events in the earthquake area and set the inflow point,the boundary point of erosion and accumulation,at the end bed of the channel erosion according to the process mechanism of debris flow. At the same time,in order to determine the flow curve of the break debris flow,parameters of dam around channel outlets were input to the Breach model to obtain the simulation flow curve that matched the actual flow,the simulation was carried out by inputting the flow curve with the consideration of the volume concentration in the inflow point. The simulation results were compared with the actual situations of outbreak using the precision evaluation model,the results showed that the inflow point on the boundary of accumulation and erosion was suitable for the outburst debris flow,which can provide scientific reference for the accuracy and feasibility of applying the FLO-2 D model in the runout scale prediction of the dam-break debris flow.
引文
[1]刘希林.我国泥石流危险度评价研究:回顾与展望[J].自然灾害学报,2002,11(4):1-8.
[2]唐川,周钜乾,朱静,等.泥石流堆积扇危险度分区评价的数值模拟研究[J].灾害学,1994(4):7-13.
[3]韦方强,胡凯衡,J.L.Lopez,等.泥石流危险性动量分区方法与应用[J].科学通报,2003,48(3):298-301.
[4] Cetina M,Rajar R,Hojnik T,et al. Case study:numerical simulations of debris flow below Stoze,Slovenia[J]. Journal of Hydraulic Engineering,2006,132(2):121-130.
[5] Jakob M,Mc Dougall S,Weatherly H,et al. Debris-flow simulations on Cheekye River,British Columbia[J]. Landslides,2013b,10(6):685-699.
[6]张鹏,马金珠,舒和平,等.基于FLO-2D模型的泥石流运动冲淤数值模拟[J].兰州大学学报(自然科学版),2014(3):363-368.
[7] Lin J Y,Yang M D,Lin B R,et al. Risk assessment of debris flows in Songhe Stream,Taiwan[J]. Engineering Geology,2011,123(1):100-112.
[8] Chang M,Tang C,Asch T W J V,et al. Hazard assessment of debris flows in the Wenchuan earthquake-stricken area,South West China[J].Landslides,2017,2017(5):1783-1792.
[9]黄勋,唐川.基于数值模拟的泥石流灾害定量风险评价[J].地球科学进展,2016,31(10):1047-1055.
[10]刘鑫磊,唐川,方群生,等.基于数值模拟的溃决型泥石流危险性评价研究[J].泥沙研究,2017,42(6):28-34.
[11] O'Brien J S. FLO-2D Users manual version 2009[R]. FLO-2D Software Inc.,10.
[12]方群生.震区溃决型泥石流冲出量特征及预测方法研究[D].成都:成都理工大学,2016.
[13] Kim S,Paik J,Kim K S. Run-out modeling of debris flows in Mt. Umyeon using FLO-2D[J]. Chemical Immunology,2013,33(3):13-33.
[14] Fread D L. BREACH,an erosion model for earthen dam failures[M]. Hydrologic Research Laboratory,National Weather Service,NOAA,1988.
[15] Li M H,Sung R T,Dong J J,et al. The formation and breaching of a short-lived landslide dam at Hsiaolin Village,Taiwan-Part II:Simulation of debris flow with landslide dam breach[J]. Engineering Geology,2011,123(1):60-71.
[16] Fan X,Tang C X,van Westen C J,et al. Simulating dam-breach flood scenarios of the Tangjiashan landslide dam induced by the Wenchuan Earthquake[J]. Natural Hazards and Earth System Sciences,2012,12(10):3031-3044.
[17] Jakob M,Holm K,Weatherly H,et al. Debris flood risk assessment for Mosquito Creek,British Columbia,Canada[J]. Natural hazards,2013a,65(3):1653-1681.
[18]唐川,李为乐,丁军,等.汶川震区映秀镇"8·14"特大泥石流灾害调查[J].地球科学-中国地质大学学报,2011,36(1):172-180.
[19] Luna BQ,Blahut J,van Westen CJ,et al. The application of numerical debris flow modelling for the generation of physical vulnerability curves[J]. Natural Hazards and Earth System Science,2011,11(7):2047-2060.
[20] Prochaska A B,Santi P M,Higgins J D,et al. Debris-flow runout predictions based on the average channel slope(ACS). Eng Geol[J]. Engineering Geology,2008,98(1):29-40.
[21]铁永波.强震区城镇泥石流灾害风险评价方法与体系研究[D].成都:成都理工大学,2009.
[22] Melelli L,Taramelli A. An example of debris-flows hazard modeling using GIS[J]. Natural Hazards&Earth System Sciences,2004,4(3):347-358.
[23] Prochaska A B,Santi P M,Higgins J D,et al. Debris-flow runout predictions based on the Average Channel Slope(ACS)[J]. Engineering Geology,2008,98(1):29-40.
[24]曾超,崔鹏,葛永刚,等.四川汶川七盘沟“7·11”泥石流破坏建筑物的特征与力学模型[J].地球科学与环境学报,2014,36(2):81-91.
[25]陈宁生,崔鹏,刘中港,等.基于黏土颗粒含量的泥石流容重计算[J].中国科学:技术科学,2003,33(S1):164-174.
[26]黄勋.强震区大型泥石流动力特性与风险量化研究[D].成都:成都理工大学,2015.
[27] Ouyang C,He S,Tang C. Numerical analysis of dynamics of debris flow over erodible beds in Wenchuan earthquake-induced area[J]. Engineering Geology,2015,194:62-72.
[28] Scheidl C,Rickenmann D. Empirical prediction of debris-flow mobility and deposition on fans[J]. Earth Surface Processes and Landforms,2010,35(2):157-173.
[2]唐川,周钜乾,朱静,等.泥石流堆积扇危险度分区评价的数值模拟研究[J].灾害学,1994(4):7-13.
[3]韦方强,胡凯衡,J.L.Lopez,等.泥石流危险性动量分区方法与应用[J].科学通报,2003,48(3):298-301.
[4] Cetina M,Rajar R,Hojnik T,et al. Case study:numerical simulations of debris flow below Stoze,Slovenia[J]. Journal of Hydraulic Engineering,2006,132(2):121-130.
[5] Jakob M,Mc Dougall S,Weatherly H,et al. Debris-flow simulations on Cheekye River,British Columbia[J]. Landslides,2013b,10(6):685-699.
[6]张鹏,马金珠,舒和平,等.基于FLO-2D模型的泥石流运动冲淤数值模拟[J].兰州大学学报(自然科学版),2014(3):363-368.
[7] Lin J Y,Yang M D,Lin B R,et al. Risk assessment of debris flows in Songhe Stream,Taiwan[J]. Engineering Geology,2011,123(1):100-112.
[8] Chang M,Tang C,Asch T W J V,et al. Hazard assessment of debris flows in the Wenchuan earthquake-stricken area,South West China[J].Landslides,2017,2017(5):1783-1792.
[9]黄勋,唐川.基于数值模拟的泥石流灾害定量风险评价[J].地球科学进展,2016,31(10):1047-1055.
[10]刘鑫磊,唐川,方群生,等.基于数值模拟的溃决型泥石流危险性评价研究[J].泥沙研究,2017,42(6):28-34.
[11] O'Brien J S. FLO-2D Users manual version 2009[R]. FLO-2D Software Inc.,10.
[12]方群生.震区溃决型泥石流冲出量特征及预测方法研究[D].成都:成都理工大学,2016.
[13] Kim S,Paik J,Kim K S. Run-out modeling of debris flows in Mt. Umyeon using FLO-2D[J]. Chemical Immunology,2013,33(3):13-33.
[14] Fread D L. BREACH,an erosion model for earthen dam failures[M]. Hydrologic Research Laboratory,National Weather Service,NOAA,1988.
[15] Li M H,Sung R T,Dong J J,et al. The formation and breaching of a short-lived landslide dam at Hsiaolin Village,Taiwan-Part II:Simulation of debris flow with landslide dam breach[J]. Engineering Geology,2011,123(1):60-71.
[16] Fan X,Tang C X,van Westen C J,et al. Simulating dam-breach flood scenarios of the Tangjiashan landslide dam induced by the Wenchuan Earthquake[J]. Natural Hazards and Earth System Sciences,2012,12(10):3031-3044.
[17] Jakob M,Holm K,Weatherly H,et al. Debris flood risk assessment for Mosquito Creek,British Columbia,Canada[J]. Natural hazards,2013a,65(3):1653-1681.
[18]唐川,李为乐,丁军,等.汶川震区映秀镇"8·14"特大泥石流灾害调查[J].地球科学-中国地质大学学报,2011,36(1):172-180.
[19] Luna BQ,Blahut J,van Westen CJ,et al. The application of numerical debris flow modelling for the generation of physical vulnerability curves[J]. Natural Hazards and Earth System Science,2011,11(7):2047-2060.
[20] Prochaska A B,Santi P M,Higgins J D,et al. Debris-flow runout predictions based on the average channel slope(ACS). Eng Geol[J]. Engineering Geology,2008,98(1):29-40.
[21]铁永波.强震区城镇泥石流灾害风险评价方法与体系研究[D].成都:成都理工大学,2009.
[22] Melelli L,Taramelli A. An example of debris-flows hazard modeling using GIS[J]. Natural Hazards&Earth System Sciences,2004,4(3):347-358.
[23] Prochaska A B,Santi P M,Higgins J D,et al. Debris-flow runout predictions based on the Average Channel Slope(ACS)[J]. Engineering Geology,2008,98(1):29-40.
[24]曾超,崔鹏,葛永刚,等.四川汶川七盘沟“7·11”泥石流破坏建筑物的特征与力学模型[J].地球科学与环境学报,2014,36(2):81-91.
[25]陈宁生,崔鹏,刘中港,等.基于黏土颗粒含量的泥石流容重计算[J].中国科学:技术科学,2003,33(S1):164-174.
[26]黄勋.强震区大型泥石流动力特性与风险量化研究[D].成都:成都理工大学,2015.
[27] Ouyang C,He S,Tang C. Numerical analysis of dynamics of debris flow over erodible beds in Wenchuan earthquake-induced area[J]. Engineering Geology,2015,194:62-72.
[28] Scheidl C,Rickenmann D. Empirical prediction of debris-flow mobility and deposition on fans[J]. Earth Surface Processes and Landforms,2010,35(2):157-173.