震后都汶公路沿线泥石流沟堵江危险性评估
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摘要
震后泥石流松散物质显著增多,临界雨量降低,导致泥石流暴发频率增加、规模增大,从而使震后灾区泥石流堵江事件频繁发生,给灾区带来严重的二次灾害。为了评价震后泥石流堵江概率大小,本文在野外考察基础上,获得研究区泥石流沟基础数据,并根据水文模型计算不同频率下的泥石流规模;在此基础上利用泥石流堵江公式,获取研究区域泥石流堵江危险程度(数值),并结合研究区域已发生的泥石流堵江事件,界定了泥石流堵江公式的临界值,使之能够更加准确用来判定泥石流堵江概率,并对5.12地震极震区都汶公路沿线的7条泥石流在不同频率下的泥石流堵江概率进行评价。评价结果显示:牛眠沟和关山沟在暴发50a及其以上泥石流时,会发生堵江;烧房沟、红椿沟和磨子沟在暴发10a及其以上泥石流时,会发生堵江事件;洱沟和太平沟在暴发5a及其以上泥石流时便可能发生堵江;上述泥石流沟一旦发生堵江,便会给映秀镇和都汶公路带来严重灾难。通过本文获取的堵江临界值可以作为判定泥石流堵江的参考标准,为泥石流防治、预报提供参考,同时可以为灾后重建和预防二次灾害提供科学借鉴。
The total amount of the loose masses due to collapses and landslides by Wenchuan Earthquake reached about 28×108m3.the loose masses can provide abundant materials for debris flows for long term.The critical rainfall has decreased significantly.The debris flow events have occurred at high frequency and in group.Their discharges have increased.Blocking of main rivers by debris flows have occurred more frequently post the earthquake and led serious secondary disasters in the quake-hit areas.In order to evaluate the probability of blocking river by debris flow,the basic data of debris flow gullies are obtained on the basis of field investigation and scale in different precipitation frequency according to a hydrological model.Then based on the above data and the differentiation formula of debris flow blocking river,this paper assesses the degree of debris flow blocking main river of the study area.It then defines the threshold value of the differentiation formula combined with debris flows that have occurred in the study area and blocked rivers.As a result,it can be used to determine the probability of debris blocking river more accurately.Seven debris flow gullies of the study area are evaluated at different precipitation frequencies.The results show that the debris flow of Niumian gully and Guanshan gully can block the Minjing river under the 50 years return period precipitation.The debris flow of Shaofang gully,Hongchun Gully and Mozi gully can block the Minjing river under the 10 years return period precipitation.The debris flow of Er gully and Taiping gully can block the Minjing river under the 5 years return period precipitation.The assessment result agrees with the phenomena of field investigation and can provide scientific supports for the prevention,elusion and mitigation of debris flow hazards and reconstruction project in the earthquake area.
The total amount of the loose masses due to collapses and landslides by Wenchuan Earthquake reached about 28×108m3.the loose masses can provide abundant materials for debris flows for long term.The critical rainfall has decreased significantly.The debris flow events have occurred at high frequency and in group.Their discharges have increased.Blocking of main rivers by debris flows have occurred more frequently post the earthquake and led serious secondary disasters in the quake-hit areas.In order to evaluate the probability of blocking river by debris flow,the basic data of debris flow gullies are obtained on the basis of field investigation and scale in different precipitation frequency according to a hydrological model.Then based on the above data and the differentiation formula of debris flow blocking river,this paper assesses the degree of debris flow blocking main river of the study area.It then defines the threshold value of the differentiation formula combined with debris flows that have occurred in the study area and blocked rivers.As a result,it can be used to determine the probability of debris blocking river more accurately.Seven debris flow gullies of the study area are evaluated at different precipitation frequencies.The results show that the debris flow of Niumian gully and Guanshan gully can block the Minjing river under the 50 years return period precipitation.The debris flow of Shaofang gully,Hongchun Gully and Mozi gully can block the Minjing river under the 10 years return period precipitation.The debris flow of Er gully and Taiping gully can block the Minjing river under the 5 years return period precipitation.The assessment result agrees with the phenomena of field investigation and can provide scientific supports for the prevention,elusion and mitigation of debris flow hazards and reconstruction project in the earthquake area.
引文
[1]Zhuang JQ,Cui P,Ge YG,et al.Probability assessment of riverblocking by debris flow associated with the Wenchuan earthquake.International Journal of Remote Sensing,2010,31(13):1～14.
[2]Zhuang JQ,Cui P,Hu KH,et al.Characteristics of earthquake-trig-gered landslides and post-earthquake debris flows in Beichuancounty.Journal of Mountain Science,2010,7(3):207～214.
[3]唐川,梁京涛.汶川震区北川9.24暴雨泥石流特征研究[J].工程地质学报,2008,16(6):751～758.Tang Chuan,Liang Jingtao.Characteristics of debris flows in Bei-chuan epicenter of the Wenchuan earthquake triggered by rainstorm on 9.24.Journal of Engineering Geology,2008,16(6):751～758.
[4]徐强.四川省8.13特大泥石流灾害特点、成因与启示[J].工程地质学报,2010,18(5):596～608.Xu Qiang.The 8.13 catastrophic debris flow in Sichuan province:Characteristics,mechanism and suggestion.Journal of EngineeringGeology,2010,18(5):610～621.
[5]游勇,柳金峰,陈兴长.“5.12”地震后北川苏保河流域泥石流危害及特征[J].山地学报,2010,28(3):358～366.You Yong,Liu Jinfeng,Chen Xingzhang.Debrisflow and its charac-teristics of Subao river in Beichuan county after“5.12”Wenchuanearthquake.Journal of Mountain Science,2010,28(3):358～366.
[6]崔鹏,庄建琦,陈兴长,等.汶川地震区震后泥石流活动特征与防治对策[J].四川大学学报(工程科学版),2010,42(5):10～19.Cui Peng,Zhuang Jjianqi,Chen Xingzhang,et al.Characteristicsand countermeasures of debris flow in Wenchuan area after theearthquake,Journal of Sichuan University,2010,42(5):10～19.
[7]胡凯衡,葛永刚,崔鹏,等.对甘肃舟曲特大泥石流灾害的初步认识[J].山地学报,2010,28(5):628～634.Hu Kaiheng,Ge Yonggang,Cui Peng,et al.Preliminaryanalysis ofextra-large-scale debris flow disaster in Zhouqu county of Gansuprovince,Journal of Mountain Science,2010,28(5):628～634.
[8]周必凡,李德基,罗德富,等.泥石流防治指南[M].北京:科学出版社,1991,125～129.Zhou Bifan,Li Deji,Luo Defu,et al.The Guidline of the DebrisFlow Mitigation.Beijing:Science Press,1991,125～129.
[9]匡尚富.汇流部泥石流的特性和淤积过程的研究[J].泥沙研究,1995,(1):1～10.Kuang Shangfu.Study on behaviors and deposit processes of debrisflow at the confluence.Journal of Sediment Research,1995,(1):1～10.
[10]党超,程尊兰,刘晶晶.泥石流堵塞主河条件[J].山地学报,2009,27(5):557～563.Dang Chao,Cheng Zunlan,Liu Jingjing.Critical conditions fordam-forming due to injunction of debris Flow into main-stream.Journal of Mountain Science,2009,27(5):557～563.
[11]徐永年,匡尚富,黄永键,等.泥石流入汇的危险性判别指标[J].自然灾害学报,2002,11(3):33～38.Xu Yongnian,Kuang Shangfu,Huang Yongjian,et al.Hazard-de-ciding indices for convergence of debris flow.Journal of NaturalDisasters,2002,11(3):33～38.
[12]陈德明,王兆印,何耘.泥石流入汇对河流影响的实验研究[J].泥沙研究,2002,6(3):22～28.Chen Deming,Wang Zhaoyin,He yun.Experimental study on thefluvial process of debris flow discharging into a river.Journal ofSediment Research,2002,6(3):22～28.
[13]何易平.泥石流对山区河流的影响(博士论文)[D].成都:中国科学院成都山地灾害与环境研究所,2003.He Yiping.InfluencedDebris Flow River Channel ChangedMountains.Chengdu:Institute of Mountain Hazard and Environ-ment,Chinese Academy of Sciences,2003.
[14]刘希林,王全才,孔纪名,等.都(江堰)汶(川)公路泥石流危险性评价及活动趋势[J].防灾减灾工程学报,2004,24(1):41～46.Liu Xilin,Wang Quancai,Kong Jiming,et al.Hazard assessmentof debris flows and their developing trend along Dujiangyan-Wen-chuan highway.Journal of Seismology,2004,24(1):41～46.
[15]苏强平,汪西林,关文彬.基于GIS下的岷江干旱河谷地区泥石流发生域危险性评价[J].中国水土保持科学,2004,2(2):98～102.Su Qiangping,Wang Xilin,Guan Wenbin.Risk assessment ofdebris flow in dry valley region of Minjiang river basin based onGIS.Science of Soil and Water Conservation,2004,2(2):98～102.
[16]孟国才,王士革,谢洪,等.岷江上游泥石流灾害特征分析[J].灾害学,2005,20(3):95～98.Meng Guocai,Wang Shige,Xie Hong,et al.Characteristics ofdebris flow disasters in the upper reaches of Minjiang riv-er.Journal of Catastrophology,2005,20(3):95～98.
[17]庄建琦,崔鹏,葛永刚,等.5.12汶川地震崩塌滑坡分布特征与影响因子分析[J].地质科技情报,2009,28(2):16～21.Zhuang Jianqi,Cui Peng,Ge Yonggang,et al.Distribution charac-teristics and impact factors assessment of collapses and landslidescaused by 5.12 Wenchuan earthquake.Geological Science andTechnology Information,2009,28(2):16～21.
[18]陈晓清,崔鹏,赵万玉.汶川地震区泥石流灾害工程防治时机的研究[J].四川大学学报(工程科学版),2009,41(3):125～130.Chen Xiaoqing,Cui Peng,Zhao Wanyu.Optimal timing for thecontrol of debris flow in Wenchuan earthquake area.Journal ofSi-chuan University(Engineering Science Edition),2009,41(3):125～130.
[19]郭志学,曹叔尤,刘兴年,等.泥石流堵江影响因素试验研究[J].水利学报,2004,(11):39～45.Guo Zhixue,Cao Shuyong,Liu Xingnian,et al.Experimental studyon parameters affecting the river-blocking due to debrisflow.Journal of Hydraulic Engineering,2004,(11):39～45.
[20]Chen XZ,Cui P,You Y,et al.Post-earthquake changes and pre-diction of debris flow scales in Subao river valley,Beichuan coun-ty,Sichuan province,China.Environmental Earth Sciences,DOI:10.1007/s12665-011-0949-4(Online First).
[21]胡凯衡,崔鹏,游勇,等.汶川灾区泥石流峰值流量的非线性雨洪修正法[J].四川大学学报(工程科学版),2010,42(5):52～57.Hu Kaiheng,Cui Peng,You Yong,et al.Nonlinear modified floodmethod for calculating the debris-flow peak discharge in Wen-chuan earthquake region.Journal of Sichuan University(Engineer-ing Science Edition),2010,42(5):52～57.
[22]陈晓清,李智广,崔鹏,等.5.12汶川地震重灾区水土流失初步估算[J].山地学报,2009,27(1):122～127.Chen Xiaoqing,Li Zhiguang,Cui Peng,et al.Estimation of soil e-rosion caused by the 5.12 Wenchuan earthquake.Journal ofMountain Science,2009,27(1):122～127.
[2]Zhuang JQ,Cui P,Hu KH,et al.Characteristics of earthquake-trig-gered landslides and post-earthquake debris flows in Beichuancounty.Journal of Mountain Science,2010,7(3):207～214.
[3]唐川,梁京涛.汶川震区北川9.24暴雨泥石流特征研究[J].工程地质学报,2008,16(6):751～758.Tang Chuan,Liang Jingtao.Characteristics of debris flows in Bei-chuan epicenter of the Wenchuan earthquake triggered by rainstorm on 9.24.Journal of Engineering Geology,2008,16(6):751～758.
[4]徐强.四川省8.13特大泥石流灾害特点、成因与启示[J].工程地质学报,2010,18(5):596～608.Xu Qiang.The 8.13 catastrophic debris flow in Sichuan province:Characteristics,mechanism and suggestion.Journal of EngineeringGeology,2010,18(5):610～621.
[5]游勇,柳金峰,陈兴长.“5.12”地震后北川苏保河流域泥石流危害及特征[J].山地学报,2010,28(3):358～366.You Yong,Liu Jinfeng,Chen Xingzhang.Debrisflow and its charac-teristics of Subao river in Beichuan county after“5.12”Wenchuanearthquake.Journal of Mountain Science,2010,28(3):358～366.
[6]崔鹏,庄建琦,陈兴长,等.汶川地震区震后泥石流活动特征与防治对策[J].四川大学学报(工程科学版),2010,42(5):10～19.Cui Peng,Zhuang Jjianqi,Chen Xingzhang,et al.Characteristicsand countermeasures of debris flow in Wenchuan area after theearthquake,Journal of Sichuan University,2010,42(5):10～19.
[7]胡凯衡,葛永刚,崔鹏,等.对甘肃舟曲特大泥石流灾害的初步认识[J].山地学报,2010,28(5):628～634.Hu Kaiheng,Ge Yonggang,Cui Peng,et al.Preliminaryanalysis ofextra-large-scale debris flow disaster in Zhouqu county of Gansuprovince,Journal of Mountain Science,2010,28(5):628～634.
[8]周必凡,李德基,罗德富,等.泥石流防治指南[M].北京:科学出版社,1991,125～129.Zhou Bifan,Li Deji,Luo Defu,et al.The Guidline of the DebrisFlow Mitigation.Beijing:Science Press,1991,125～129.
[9]匡尚富.汇流部泥石流的特性和淤积过程的研究[J].泥沙研究,1995,(1):1～10.Kuang Shangfu.Study on behaviors and deposit processes of debrisflow at the confluence.Journal of Sediment Research,1995,(1):1～10.
[10]党超,程尊兰,刘晶晶.泥石流堵塞主河条件[J].山地学报,2009,27(5):557～563.Dang Chao,Cheng Zunlan,Liu Jingjing.Critical conditions fordam-forming due to injunction of debris Flow into main-stream.Journal of Mountain Science,2009,27(5):557～563.
[11]徐永年,匡尚富,黄永键,等.泥石流入汇的危险性判别指标[J].自然灾害学报,2002,11(3):33～38.Xu Yongnian,Kuang Shangfu,Huang Yongjian,et al.Hazard-de-ciding indices for convergence of debris flow.Journal of NaturalDisasters,2002,11(3):33～38.
[12]陈德明,王兆印,何耘.泥石流入汇对河流影响的实验研究[J].泥沙研究,2002,6(3):22～28.Chen Deming,Wang Zhaoyin,He yun.Experimental study on thefluvial process of debris flow discharging into a river.Journal ofSediment Research,2002,6(3):22～28.
[13]何易平.泥石流对山区河流的影响(博士论文)[D].成都:中国科学院成都山地灾害与环境研究所,2003.He Yiping.InfluencedDebris Flow River Channel ChangedMountains.Chengdu:Institute of Mountain Hazard and Environ-ment,Chinese Academy of Sciences,2003.
[14]刘希林,王全才,孔纪名,等.都(江堰)汶(川)公路泥石流危险性评价及活动趋势[J].防灾减灾工程学报,2004,24(1):41～46.Liu Xilin,Wang Quancai,Kong Jiming,et al.Hazard assessmentof debris flows and their developing trend along Dujiangyan-Wen-chuan highway.Journal of Seismology,2004,24(1):41～46.
[15]苏强平,汪西林,关文彬.基于GIS下的岷江干旱河谷地区泥石流发生域危险性评价[J].中国水土保持科学,2004,2(2):98～102.Su Qiangping,Wang Xilin,Guan Wenbin.Risk assessment ofdebris flow in dry valley region of Minjiang river basin based onGIS.Science of Soil and Water Conservation,2004,2(2):98～102.
[16]孟国才,王士革,谢洪,等.岷江上游泥石流灾害特征分析[J].灾害学,2005,20(3):95～98.Meng Guocai,Wang Shige,Xie Hong,et al.Characteristics ofdebris flow disasters in the upper reaches of Minjiang riv-er.Journal of Catastrophology,2005,20(3):95～98.
[17]庄建琦,崔鹏,葛永刚,等.5.12汶川地震崩塌滑坡分布特征与影响因子分析[J].地质科技情报,2009,28(2):16～21.Zhuang Jianqi,Cui Peng,Ge Yonggang,et al.Distribution charac-teristics and impact factors assessment of collapses and landslidescaused by 5.12 Wenchuan earthquake.Geological Science andTechnology Information,2009,28(2):16～21.
[18]陈晓清,崔鹏,赵万玉.汶川地震区泥石流灾害工程防治时机的研究[J].四川大学学报(工程科学版),2009,41(3):125～130.Chen Xiaoqing,Cui Peng,Zhao Wanyu.Optimal timing for thecontrol of debris flow in Wenchuan earthquake area.Journal ofSi-chuan University(Engineering Science Edition),2009,41(3):125～130.
[19]郭志学,曹叔尤,刘兴年,等.泥石流堵江影响因素试验研究[J].水利学报,2004,(11):39～45.Guo Zhixue,Cao Shuyong,Liu Xingnian,et al.Experimental studyon parameters affecting the river-blocking due to debrisflow.Journal of Hydraulic Engineering,2004,(11):39～45.
[20]Chen XZ,Cui P,You Y,et al.Post-earthquake changes and pre-diction of debris flow scales in Subao river valley,Beichuan coun-ty,Sichuan province,China.Environmental Earth Sciences,DOI:10.1007/s12665-011-0949-4(Online First).
[21]胡凯衡,崔鹏,游勇,等.汶川灾区泥石流峰值流量的非线性雨洪修正法[J].四川大学学报(工程科学版),2010,42(5):52～57.Hu Kaiheng,Cui Peng,You Yong,et al.Nonlinear modified floodmethod for calculating the debris-flow peak discharge in Wen-chuan earthquake region.Journal of Sichuan University(Engineer-ing Science Edition),2010,42(5):52～57.
[22]陈晓清,李智广,崔鹏,等.5.12汶川地震重灾区水土流失初步估算[J].山地学报,2009,27(1):122～127.Chen Xiaoqing,Li Zhiguang,Cui Peng,et al.Estimation of soil e-rosion caused by the 5.12 Wenchuan earthquake.Journal ofMountain Science,2009,27(1):122～127.
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