极震区泥石流流量计算方法的研究
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摘要
极震区形成了大量高位能型滑坡和震裂山体,震裂山体在重力和后期降雨联合作用下,震裂面延伸、扩展和贯穿,从而形成贯通性破坏面,破坏结构,这使震裂潜在型物源转变为新崩滑体物源。极震区物源与非地震区物源迥异的物理性质,使泥石流启动的临界条件降低,导致泥石流流量在物源形成、汇流和运动过程都具有放大效应,现有的泥石流峰值流量计算方法在极震区的应用具有明显的局限性。综合考虑了地震放大效应、沟道纵坡降、沟道宽度、水动力条件和泥石流物理性质等因素对泥石流流量的影响,建立了泥石流流量-冲刷模型。对比实例验算结果和实测流量,吻合较好,说明本文计算公式对于极震区的适用性和有效性。所得成果可用以估算汶川地震中极震区泥石流流量,对泥石流防治措施的选择有参考价值。
Plenty of landslides with high potential energy and shattered mountains have been formed in meizoseismal areas. Under combined effect of gravity and rainfall,shattered surfaces start to extend and penetrate. Gradually they develop into a penetrating fracture face which breaks the internal structure of rock and soil. As a result,this process turns sources of potential shattering cracks into new landslides. The different physical properties between meizoseismal and non-seismic sources,coupled with the reduced critical condition of initiating debris flow exert an amplification effect on source formation,flow routing and movement. When applied to the meizoseismal areas,the existing methods of calculating debris flow peak discharge bear obvious limitations. This paper takes into account the fact that the discharge of debris flow is influenced by factors such as the seismic amplification effect,channel gradient and width,hydrodynamic conditions and physical properties of debris flow,and established a flow-erosion model. By comparison,the calculation result of examples by using the model is in good agreement with the actual value,which proves the applicability and validity of the formula suggested in this paper for meizoseismal areas. The results can be used for estimating discharge of debris flow in meizoseismal areas of Wenchuan earthquake and may give a reference to choosing prevention and control measures of debris flow.
Plenty of landslides with high potential energy and shattered mountains have been formed in meizoseismal areas. Under combined effect of gravity and rainfall,shattered surfaces start to extend and penetrate. Gradually they develop into a penetrating fracture face which breaks the internal structure of rock and soil. As a result,this process turns sources of potential shattering cracks into new landslides. The different physical properties between meizoseismal and non-seismic sources,coupled with the reduced critical condition of initiating debris flow exert an amplification effect on source formation,flow routing and movement. When applied to the meizoseismal areas,the existing methods of calculating debris flow peak discharge bear obvious limitations. This paper takes into account the fact that the discharge of debris flow is influenced by factors such as the seismic amplification effect,channel gradient and width,hydrodynamic conditions and physical properties of debris flow,and established a flow-erosion model. By comparison,the calculation result of examples by using the model is in good agreement with the actual value,which proves the applicability and validity of the formula suggested in this paper for meizoseismal areas. The results can be used for estimating discharge of debris flow in meizoseismal areas of Wenchuan earthquake and may give a reference to choosing prevention and control measures of debris flow.
引文
[1]黄润秋.汶川地震地质灾害研究[M].北京:科学出版社,2009.HUANG Runqiu.Geohazard Assessment of the Wenchuan Earthquake[M].Beijing:Science Press,2009.(in Chinese)
[2]Carter,Cannon,Santi,et al.Empirical models to predict the volumes of debris flows generated by recently burned basins in the western U.S.[J].Geomorphology,2008,96(3/4):339-354.
[3]陈晓清,陈宁生,崔鹏.冰川终碛湖溃决泥石流流量计算[J].冰川冻土,2004,26(3):357-362.CHEN Xiaoqing,CHEN Ningsheng,CUI Peng.Calcuation of discharge of flow induced by glacier lake outburst[J].Journal of Glaciology and Geocryology,2004,26(3):357-362.(in Chinese)
[4]黄凯,陈晓清,李强等.西藏地区小流域泥石流洪峰流量计算方法与改进[J].水土保持通报,2012,32(6):123-128.HUANG Kai,CHEN Xiaoqing,LI Qiang,et al.Modified method for peak discharge calculation of debris flows in Southwest Area of Tibet[J].Bulletin of Soil and Water Conservation,2012,32(6):123-128.(in Chinese)
[5]弗莱施曼C M.泥石流[M].北京:科学出版社,1986:218-231.Fleishman C M.Debris Flow[M].Beijing:Science Press,1986:218-231.(in Chinese)
[6]冯文凯,黄润秋,许强.地震波效应与山体斜坡震裂机理深入分析[J].西北地震学报,2011,3(1):20-25.FENG Wenkai,HUANG Runqiu,XU Qiang.In-depth analysis of the seismic wave effect and slope shattered mechanism[J].Northwestern Seismological Journal,2011,3(1):20-25.(in Chinese)
[7]Zheng-yi Feng.The seismic signatures of the surge wave from the 2009 Xiaolin landslide-dam breach in Taiwan[J].Hydrological Process,2012,26:1342-1351.
[8]Grosta G,Imposimato S,Roddeman D.Numerical modeling of entrainment in rock and debris-avalanches[J].Enginerring Geology,2009,109(1-2):135-145.
[9]陈宁生,高延超,李东风,等.丹巴县邛山沟特大灾害性泥石流汇流过程分析[J].自然灾害学报,2004,13(3):104-108.CHEN Ningsheng,Gao Yanchao,Li Dongfeng,et al.Conflux process analysis of disastrous debirs flow in Qiongshan ravine,Danba,Sichuan province[J].Journal of Nature Disasters,2004,13(3):104-108.(in Chinese)
[10]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,2009:1-161.TIE Rongbo.The Methodology and Framework Study of Urban Debris Flow Risk Assessment[D].Chengdu:Chengdu University of Technology,2009:1-161.(in Chinese)
[11]梁志勇,匡尚富,王兆印,等.高含沙洪水冲刷规律的探讨[J].泥沙研究,1999,6(12):68-73.LIANG Zhiyong,KUANG Shangfu,WANG Zhaoyin,et al.Scour rate of hyperconcentrated flow[J].Journal of Sediment Research,1999,6(12):68-73.(in Chinese)
[12]朱兴华,崔鹏,周公旦,等.稀性泥石流冲刷规律的试验研究[J].水利学报,2012,43(增刊2):85-91.ZHU Xinghua,CUI Peng,ZHOU Gongdan,et al.Experimental study on the erosion law of debris flow[J].Journal of Hydraulic Engineering,2012,43(S2):85-91.(in Chinese)
[2]Carter,Cannon,Santi,et al.Empirical models to predict the volumes of debris flows generated by recently burned basins in the western U.S.[J].Geomorphology,2008,96(3/4):339-354.
[3]陈晓清,陈宁生,崔鹏.冰川终碛湖溃决泥石流流量计算[J].冰川冻土,2004,26(3):357-362.CHEN Xiaoqing,CHEN Ningsheng,CUI Peng.Calcuation of discharge of flow induced by glacier lake outburst[J].Journal of Glaciology and Geocryology,2004,26(3):357-362.(in Chinese)
[4]黄凯,陈晓清,李强等.西藏地区小流域泥石流洪峰流量计算方法与改进[J].水土保持通报,2012,32(6):123-128.HUANG Kai,CHEN Xiaoqing,LI Qiang,et al.Modified method for peak discharge calculation of debris flows in Southwest Area of Tibet[J].Bulletin of Soil and Water Conservation,2012,32(6):123-128.(in Chinese)
[5]弗莱施曼C M.泥石流[M].北京:科学出版社,1986:218-231.Fleishman C M.Debris Flow[M].Beijing:Science Press,1986:218-231.(in Chinese)
[6]冯文凯,黄润秋,许强.地震波效应与山体斜坡震裂机理深入分析[J].西北地震学报,2011,3(1):20-25.FENG Wenkai,HUANG Runqiu,XU Qiang.In-depth analysis of the seismic wave effect and slope shattered mechanism[J].Northwestern Seismological Journal,2011,3(1):20-25.(in Chinese)
[7]Zheng-yi Feng.The seismic signatures of the surge wave from the 2009 Xiaolin landslide-dam breach in Taiwan[J].Hydrological Process,2012,26:1342-1351.
[8]Grosta G,Imposimato S,Roddeman D.Numerical modeling of entrainment in rock and debris-avalanches[J].Enginerring Geology,2009,109(1-2):135-145.
[9]陈宁生,高延超,李东风,等.丹巴县邛山沟特大灾害性泥石流汇流过程分析[J].自然灾害学报,2004,13(3):104-108.CHEN Ningsheng,Gao Yanchao,Li Dongfeng,et al.Conflux process analysis of disastrous debirs flow in Qiongshan ravine,Danba,Sichuan province[J].Journal of Nature Disasters,2004,13(3):104-108.(in Chinese)
[10]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,2009:1-161.TIE Rongbo.The Methodology and Framework Study of Urban Debris Flow Risk Assessment[D].Chengdu:Chengdu University of Technology,2009:1-161.(in Chinese)
[11]梁志勇,匡尚富,王兆印,等.高含沙洪水冲刷规律的探讨[J].泥沙研究,1999,6(12):68-73.LIANG Zhiyong,KUANG Shangfu,WANG Zhaoyin,et al.Scour rate of hyperconcentrated flow[J].Journal of Sediment Research,1999,6(12):68-73.(in Chinese)
[12]朱兴华,崔鹏,周公旦,等.稀性泥石流冲刷规律的试验研究[J].水利学报,2012,43(增刊2):85-91.ZHU Xinghua,CUI Peng,ZHOU Gongdan,et al.Experimental study on the erosion law of debris flow[J].Journal of Hydraulic Engineering,2012,43(S2):85-91.(in Chinese)
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