四川省都江堰市龙池地区“8·13”泥石流堆积扇调查和分析

Survey and analysis of the“8.13”debris flows fan in Longchi Town of Dujiangyan City,Sichuan Province

汶川"5·12"地震后,震区泥石流等自然灾害活动频繁,与此同时,其危害性呈几何级数增长,而泥石流的堆积特征直接反应其危害程度。2010年8月13日,都江堰市龙池地区暴发了大规模的群发性泥石流灾害,共有50多条沟发生了泥石流过程,冲毁了龙池地区的地震重建区的房屋和道路。笔者通过对研究区泥石流堆积扇的野外调查,统计了36条沟的泥石流堆积扇的堆积厚度、堆积宽度、堆积长度以及堆积坡度等参数,得到了研究区泥石流堆积扇冲出距离、堆积宽度、堆积厚度以及扩散宽度与流域泥石流物源动储量、流域高差、沟口宽度等因素的关系,在此基础上,建立了泥石流堆积扇几何堆积特征统计模型,且通过震区典型泥石流的验证,统计模型具有一定实用性,可为研究区泥石流灾害防治提供一定参考。

Debris flows occur more frequently in the earthquake zone after＂5·12＂Wenchuan earthquakein 2008,meanwhile,the perniciousness of debris flow grows as geometric progression,and the accumula-tion characteristics of debris flow directly respond the harm degree. On August 13,2010,a large-scalegroup-occurring debris flow disasters broke out in more than 50 gullies of Longchi area,Dujiangyan city,destroyed the buildings and roads in earthquake reconstruction area. Statistical relationship between depos-its features,such as deposits thickness,deposits width,run out distance and diffusion rate,and drainagebasin characteristics as dynamic accumulation, drainage basins elevation and outlet width of gully, hasbeen established according to field observation of fan characteristics as deposits thickness,deposits width,run out distance,deposits gradient of 36 debris flow gullies in the study area. On this basis,a geometricstatistical model of debris flow fan was established by the characteristics of fan accumulation characteristics.The practicality of the statistical model has been verified through typical debris flow in the earthquake re-gion,which can provides certain reference for debris flow disaster prevention and control in the study areain the future.