安县雎水河流域地质灾害发育、分布及影响因素
|
摘要
安县雎水河流域属龙门山山脉与四川盆地过渡地区,地形切割强烈,地层岩性复杂,活动断裂发育,特别是"5.12"汶川特大地震后,区内地质环境变得十分脆弱,大型、特大型崩塌滑坡泥石流流十分发育,具有数量多、规模大、分布范围广,呈区域性密集分布等特征。在"成兰线雎水河段卫星遥感解译图"的基础上,通过对该流域两次详细的地质测绘调查,分析了地质灾害的发育、分布特性及其影响因素,进而对灾后重建提供一定的参考依据。研究得出的主要认识有:(1)地质灾害在流域内分布范围广、密度大、呈密集性分布,"成群成带性"现象明显;(2)地质灾害的分布与地形地貌有密切的关系,大多数地质灾害发生在高程800～1500m,坡度30°～50°的范围内;(3)地质灾害主要沿雎水河及其支流两岸发生,多呈线性分布;(4)发震断裂控制着地质灾害的分布,在断层的上下盘分布表现出明显的差异,断层上盘的地质灾害数量明显多于下盘,距发震断裂10km范围是地质灾害最为发育的区域;(5)地层岩性与地质灾害的类型有密切的关系,坚硬、较坚硬岩组中的崩塌数量远远多于软弱泥页岩、千枚岩岩组,软岩、极软岩岩组中的滑坡比坚硬岩中相对要多;(6)不同的岸坡结构控制着地质灾害的发育、分布,横向岸坡中崩滑最为发育,其次为斜向倾内层状岸坡。另外,中陡倾岸坡中的地质灾害较缓倾岸坡发育;(7)地质灾害的类型、发育分布与也与坡体结构、岩体结构及其组合特征有一定的关系。研究发现,顺层边坡中如发育有陡倾坡内的结构面,则易形成滑坡,而反倾边坡中如发育有倾坡外的结构面则更易形成崩塌。
The area along to Jushui River in Anxian city belongs to the transitional region between the Longmenshan mountain and the Sichuan basin.In this area,topography was cut strongly,and the lithologies are very complicate,and active fault well developed.Especially after the "5.12" Wenchuan great earthquake,the geological environment is getting increasingly fragile,and large-scale and super-scale geohazards,such as rockfalls,landslides and debris flows,are well developed.The geohazards have great quantity,large-scale,wide,high concentrated distribution and other properties.On the basis of "the map of remote sensing interpretation of the area along Jushui river of the Chengdu-Lanzhou railway",after two geological surveys and investigations,this paper summarized and analysed properties of the development and distribution of poor geological phenomenon and influencing factors of them.Then this will provide some degree of references for the disaster reconstruction of the region.The main consequences of this study are:(1)Geohazards in this area are widely distributed,have high density,present high concentrated distribution and distribute in groups and belts;(2)The distribution of geohazards is closely related with topography and physiognomy.Most happened in the region of height between 800 m to 1 500 m,and slope between 30°to 50°;(3)Geohazards mainly happened on both banks along the Jushui River and its tributaries and they distributed mainly in belts;(4)Geohazards are controlled by seismogenic faults in this region and most of them distributed in lines or belts along faults. Moreover,these distributed in upper wall and in lower wall have great difference,that is the number in upper is obvious big than in down.The range 10 km away from the seismogenic fault is the most developed of poor geological phenomena;(5)The lithologies are closely related with the types of poor geological phenomena.Statistical study found that the number of rockfalls happened in hard and less hard stone is far larger than in weak mud shale and phyllite,but the number of landslides happened in soft rock and extremely soft rock is relatively larger;(6)Different slope structures control the development and the distribution of poor geological phenomena. Study showed that poor geological phenomena mostly happened in horizontal slope,and secondly happened in oblique internal layered slope.In addition,poor geological phenomena happened in mid-steep bank slope are more than in less flatten slope;(7)The types and distribution of poor geological phenomena are some related with slope structure,rock mass structure and its combined features.Study found that if there are steep oblique internal structural surfaces in bedding lithologic slope,landslides easily happened in the slope,and if there are oblique external structural surfaces in Anti-dumping slope,the slope easily form rockfalls.
The area along to Jushui River in Anxian city belongs to the transitional region between the Longmenshan mountain and the Sichuan basin.In this area,topography was cut strongly,and the lithologies are very complicate,and active fault well developed.Especially after the "5.12" Wenchuan great earthquake,the geological environment is getting increasingly fragile,and large-scale and super-scale geohazards,such as rockfalls,landslides and debris flows,are well developed.The geohazards have great quantity,large-scale,wide,high concentrated distribution and other properties.On the basis of "the map of remote sensing interpretation of the area along Jushui river of the Chengdu-Lanzhou railway",after two geological surveys and investigations,this paper summarized and analysed properties of the development and distribution of poor geological phenomenon and influencing factors of them.Then this will provide some degree of references for the disaster reconstruction of the region.The main consequences of this study are:(1)Geohazards in this area are widely distributed,have high density,present high concentrated distribution and distribute in groups and belts;(2)The distribution of geohazards is closely related with topography and physiognomy.Most happened in the region of height between 800 m to 1 500 m,and slope between 30°to 50°;(3)Geohazards mainly happened on both banks along the Jushui River and its tributaries and they distributed mainly in belts;(4)Geohazards are controlled by seismogenic faults in this region and most of them distributed in lines or belts along faults. Moreover,these distributed in upper wall and in lower wall have great difference,that is the number in upper is obvious big than in down.The range 10 km away from the seismogenic fault is the most developed of poor geological phenomena;(5)The lithologies are closely related with the types of poor geological phenomena.Statistical study found that the number of rockfalls happened in hard and less hard stone is far larger than in weak mud shale and phyllite,but the number of landslides happened in soft rock and extremely soft rock is relatively larger;(6)Different slope structures control the development and the distribution of poor geological phenomena. Study showed that poor geological phenomena mostly happened in horizontal slope,and secondly happened in oblique internal layered slope.In addition,poor geological phenomena happened in mid-steep bank slope are more than in less flatten slope;(7)The types and distribution of poor geological phenomena are some related with slope structure,rock mass structure and its combined features.Study found that if there are steep oblique internal structural surfaces in bedding lithologic slope,landslides easily happened in the slope,and if there are oblique external structural surfaces in Anti-dumping slope,the slope easily form rockfalls.
引文
[1]Qi Shengwen,Xu Qiang,Liu Chunling,et al.Slope instabilities in the severest disaster areaas of5.12Wenchuan Earthquake[J].Jour-nal ofEngineering Geology,2009,17(1):44~49[祁生文,许强,刘春玲,等.汶川地震极重灾区地质背景及次生斜坡灾害空间发育规律[J].工程地质学报,2009,17(1):44~48]
[2]State Bureau of Techuical Supervisioy,Minsty of Coustmctiou of Peo-ple.Republic of Chnia Stamlarrl for Classification of Eaignieernig Rock Masses(GB50218-94).Beijing:Chnia Planning Press,1995[国家技术监督局、中华人民共和国建设部.工程岩体分级标准(GB50218-94)[S].北京:中国计划出版社,1995]
[3]Hung Runqiu,Xu Qiang.Catastrophic Landslides in China[M].Bei-jing:Science Press,2008[黄润秋,许强.中国典型灾害性滑坡[M].北京:科学出版社,2008]
[4]Parsons T,Chen J,Kirby E.Stress changes from the2008Wenchuan earthquake and increased hazard in the Sichuan basin[J].Nature,2008,454:509~510
[5]Keefer,D.K.Statistical analysis of an earthquake induced landslide distribution the1989Lom a Prieta,California eveat[J].Engineering Geology,2000,58:231~249
[6]Liu Hanchao,Chen Mingdong,Li Kewu,et al.Evaluation of Environ-mental Geology in the Reservoir Area[M].Chengdu:Chengdu Sci-ence and Technology University Press,1993:16~27[刘汉超,陈明东,黎克武,等.库区环境地质评价研究[M].成都:成都科技大学出版社,1993:16~27]
[2]State Bureau of Techuical Supervisioy,Minsty of Coustmctiou of Peo-ple.Republic of Chnia Stamlarrl for Classification of Eaignieernig Rock Masses(GB50218-94).Beijing:Chnia Planning Press,1995[国家技术监督局、中华人民共和国建设部.工程岩体分级标准(GB50218-94)[S].北京:中国计划出版社,1995]
[3]Hung Runqiu,Xu Qiang.Catastrophic Landslides in China[M].Bei-jing:Science Press,2008[黄润秋,许强.中国典型灾害性滑坡[M].北京:科学出版社,2008]
[4]Parsons T,Chen J,Kirby E.Stress changes from the2008Wenchuan earthquake and increased hazard in the Sichuan basin[J].Nature,2008,454:509~510
[5]Keefer,D.K.Statistical analysis of an earthquake induced landslide distribution the1989Lom a Prieta,California eveat[J].Engineering Geology,2000,58:231~249
[6]Liu Hanchao,Chen Mingdong,Li Kewu,et al.Evaluation of Environ-mental Geology in the Reservoir Area[M].Chengdu:Chengdu Sci-ence and Technology University Press,1993:16~27[刘汉超,陈明东,黎克武,等.库区环境地质评价研究[M].成都:成都科技大学出版社,1993:16~27]
版权所有：© 2023 中国地质图书馆 中国地质调查局地学文献中心