四川省“8·13”特大泥石流灾害成生机理与防治原则
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摘要
2010年8月12日—14日强降雨过程导致"5.12"汶川地震的极重灾区映秀镇、龙池镇、清平乡集中暴发了大面积泥石流灾害,损失惨重。针对四川"8·13"泥石流三大典型泥石流沟所表现出来的共同特点,研究地震重灾区泥石流灾害成生机理,对泥石流灾害治理及灾害预警工作具有极其重要意义。首先研究了映秀镇、龙池镇、清平乡典型泥石流灾害的基本情况及其地质环境条件,泥石流的分布规律、成生规律和表现形式。(1)本次泥石流主要集中分布在发震断裂构造带附近,呈带状分布;(2)它们在地震之前就是泥石流沟;(3)沟内斜坡稳定性原本就差,加之在"5·12"地震作用下后,稳定性更差,且有更多的物源进入到沟中,在沟内形成大大小小的堵塞体,在降雨期对地表径流起‘堵沟蓄能—溃决消能’作用,在堵塞体溃决时,流水之挟砂、抽槽等作用大大增强而形成大规模、突发性泥石流。针对这类泥石流的特点及成生机理,最后提出了相应的泥石流的防治原则:一是治沟必须与治坡相结合;二是工程措施的兴建应与其功能的维护(维修)相结合;三是防灾工程与建设开发相结合;四是泥石流监测预警应同时布置在潜在的‘堵塞体’的上下游侧。
The heavy rainfall from August 12 to 14th,2010 led to a large area of debris flow in the serious quake-hit of the '5·12' Wenchuan earthquake such as Yingxiu Town,Longchi Town and Qingping Township.It caused the serious damage.According to the common characteristics of the three typical debris flows which happened on 13th,August,exploring the formation mechanism of debris flow in earthquake-hit area has great meaning for the controlling and disaster early warning about the debris flow.This paper first introduces the basic condition and the geological environment condition about the typical debris flows in the hardest hit Yingxiu,Longchi,Qingping Township.It also explores the distribution,the formation mechanism and the performance pattern of the debris flow.First,this debris flow is mainly distributed in the vicinity of fault with the zonal distribution.Second,they are the trenches of debris flow before the earthquake.Third,the stability of the slope in the trench is poor.And on the effect of the '5·12' Wenchuan earthquake,the conditions got worse,there are more things going into the trench,which form large or small blockage.During the rainfall,the surface runoff forms the pattern of debris flow which can ditch block storage and burst of energy dissipation.When the blocking body bursts,the water runs with the sand,the pumping groove and they enhance the formation of large,sudden landslides.According to the characteristics and the mechanisms of debris flow,this paper concludes the controlling principles of earthquake debris flow.First,the comprehensive measures of controlling the gully and slope should be combined.Second,project implementation and their functions maintenance should be combined.Third,the disaster controlling of projects and the construction should be combined.We can also say that we should combine the controlling of the debris flow with the project of the slope controlling and the road reinforcement about the groove side.Fourth,the debris flow monitoring and warning should also be arranged in the potential of the plug body on the downstream side.
The heavy rainfall from August 12 to 14th,2010 led to a large area of debris flow in the serious quake-hit of the '5·12' Wenchuan earthquake such as Yingxiu Town,Longchi Town and Qingping Township.It caused the serious damage.According to the common characteristics of the three typical debris flows which happened on 13th,August,exploring the formation mechanism of debris flow in earthquake-hit area has great meaning for the controlling and disaster early warning about the debris flow.This paper first introduces the basic condition and the geological environment condition about the typical debris flows in the hardest hit Yingxiu,Longchi,Qingping Township.It also explores the distribution,the formation mechanism and the performance pattern of the debris flow.First,this debris flow is mainly distributed in the vicinity of fault with the zonal distribution.Second,they are the trenches of debris flow before the earthquake.Third,the stability of the slope in the trench is poor.And on the effect of the '5·12' Wenchuan earthquake,the conditions got worse,there are more things going into the trench,which form large or small blockage.During the rainfall,the surface runoff forms the pattern of debris flow which can ditch block storage and burst of energy dissipation.When the blocking body bursts,the water runs with the sand,the pumping groove and they enhance the formation of large,sudden landslides.According to the characteristics and the mechanisms of debris flow,this paper concludes the controlling principles of earthquake debris flow.First,the comprehensive measures of controlling the gully and slope should be combined.Second,project implementation and their functions maintenance should be combined.Third,the disaster controlling of projects and the construction should be combined.We can also say that we should combine the controlling of the debris flow with the project of the slope controlling and the road reinforcement about the groove side.Fourth,the debris flow monitoring and warning should also be arranged in the potential of the plug body on the downstream side.
引文
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[2]许强.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):610-621.
[3]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.
[4]苏鹏程,韦方强,冯汉中,等.“8.13”四川清平群发性泥石流灾害成因及其影响[J].山地学报,2011,29(3):337-347.
[5]余斌,马煜,吴雨夫.汶川地震后四川省绵竹市清平乡文家沟泥石流灾害调查研究[J].工程地质学报,2010,18(6):827-836.
[6]张自光,张志明,张顺斌.都江堰市八一沟泥石流形成条件与动力学特征分析[J].中国地质灾害与防治学报,2010,21(1):34-38.
[7]马煜,余斌,吴雨夫等.四川都江堰龙池“8.13”八一沟大型泥石流灾害研究[J],四川大学学报,2011,43(增刊1):92-98.
[8]沈军辉,朱容辰,刘维国,等.“5.12”汶川地震诱发都江堰龙池镇干沟泥石流可能性地质分析[J].山地学报,2008,26(5):513-517.
[9]李朝安,胡卸文,王良玮.山区铁路沿线泥石流泥位自动监测预警系统[J].自然灾害学报,2011,20(5):74-81.
[10]李朝安,魏鸿.西南地区泥石流灾害及防灾预警[J].中国地质灾害与防治学报,2004,15(3):34-37.
[2]许强.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):610-621.
[3]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.
[4]苏鹏程,韦方强,冯汉中,等.“8.13”四川清平群发性泥石流灾害成因及其影响[J].山地学报,2011,29(3):337-347.
[5]余斌,马煜,吴雨夫.汶川地震后四川省绵竹市清平乡文家沟泥石流灾害调查研究[J].工程地质学报,2010,18(6):827-836.
[6]张自光,张志明,张顺斌.都江堰市八一沟泥石流形成条件与动力学特征分析[J].中国地质灾害与防治学报,2010,21(1):34-38.
[7]马煜,余斌,吴雨夫等.四川都江堰龙池“8.13”八一沟大型泥石流灾害研究[J],四川大学学报,2011,43(增刊1):92-98.
[8]沈军辉,朱容辰,刘维国,等.“5.12”汶川地震诱发都江堰龙池镇干沟泥石流可能性地质分析[J].山地学报,2008,26(5):513-517.
[9]李朝安,胡卸文,王良玮.山区铁路沿线泥石流泥位自动监测预警系统[J].自然灾害学报,2011,20(5):74-81.
[10]李朝安,魏鸿.西南地区泥石流灾害及防灾预警[J].中国地质灾害与防治学报,2004,15(3):34-37.
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