桂林市岩质崩塌发育特征与影响因素
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摘要
对桂林市1980～2017年间记录或现存的118处岩质崩塌基本数据进行了统计分析和研究。结果显示:在时间上,桂林市岩质崩塌主要发生在每年3～7月份的雨季,这期间发生的岩质崩塌数占崩塌总数的62.7%,崩塌数量与降雨量成正相关,且从2005年起岩质崩塌有明显的增加趋势;空间上,桂林市岩质崩塌主要发生在上泥盆统桂林组(D_3g)、东村组(D_3d)和融县组(D_3r)厚层-块状灰岩侵蚀溶蚀作用形成的孤峰平原、峰丛洼地谷地和峰林平原地貌区,分布在这3个地貌区内的岩质崩塌分别占崩塌总数的46%、38%和15%,且大多数岩质崩塌发生在坡高50～200 m、坡角60°～90°的凸型或凹型的阳坡上;规模上,桂林市岩质崩塌以小型为主,规模一般在0.5～350 m~3。此外,桂林市岩质崩塌还具有明显的继发性特征,同一座山体(灾害点)发生的2次及2次以上崩塌数量占崩塌总数的37%。除降雨外,地质构造、人类工程活动和生物风化作用等也是引发岩质崩塌的主要诱因。桂林市岩质崩塌的失稳模式主要有拉裂-坠落模式、压剪-滑移模式、拉裂-倾倒模式、塑流-拉裂模式、孤石崩落模式和空间滑移模式,其中以孤石崩落模式和压剪-滑移模式岩质崩塌最为易发。
Study of the documented rockfall incidents during 1980-2017 and survey of 118 existing rockfalls in Guilin reveal that 62.7% of the rockfall incidents occurred during the rainy season of March through July. Apparently the likelihood of rockfall is positively proportional to the amount of rainfall and the city sees remarkably increased trend of rockfall incidents from 2005. The rockfalls occurred in karst poljes with isolated limestone towers(accounting for 46% of the total rockfalls), low land and valley areas with clustered towers(accounting for 38%), and poljes with clustered towers(accounting for 15%). These three types of karst topography are resulted from dissolution of thickly bedded limestone of the Upper Devonian Guilin(D_3g), Dongcun(D_3d) and Rongxian(D_3r) formations. Most of the rockfalls occurred on the south side of hills with slope height of 50-200 m and slope angle of 60-90°. Majority of the rockfalls in Guilin are rated at small scale(0.5-350 m~3), The survey also shows that 37% of the rockfall incidents occurred as resurgent incidents. In addition to rainfall, geological structures, biochemical weathering, such as root wedging, and human geotechnical activities, are major triggering factors for rockfalls. Failure modes of rockfall in Guilin area include tensional fracture falling, compressional shear and sliding, tensional fracture toppling, plastic flow and extensional fracturing, single-rock falling, and wedge sliding. The single-rock falling and compressional shear and sliding are dominant failure modes in Guilin.
Study of the documented rockfall incidents during 1980-2017 and survey of 118 existing rockfalls in Guilin reveal that 62.7% of the rockfall incidents occurred during the rainy season of March through July. Apparently the likelihood of rockfall is positively proportional to the amount of rainfall and the city sees remarkably increased trend of rockfall incidents from 2005. The rockfalls occurred in karst poljes with isolated limestone towers(accounting for 46% of the total rockfalls), low land and valley areas with clustered towers(accounting for 38%), and poljes with clustered towers(accounting for 15%). These three types of karst topography are resulted from dissolution of thickly bedded limestone of the Upper Devonian Guilin(D_3g), Dongcun(D_3d) and Rongxian(D_3r) formations. Most of the rockfalls occurred on the south side of hills with slope height of 50-200 m and slope angle of 60-90°. Majority of the rockfalls in Guilin are rated at small scale(0.5-350 m~3), The survey also shows that 37% of the rockfall incidents occurred as resurgent incidents. In addition to rainfall, geological structures, biochemical weathering, such as root wedging, and human geotechnical activities, are major triggering factors for rockfalls. Failure modes of rockfall in Guilin area include tensional fracture falling, compressional shear and sliding, tensional fracture toppling, plastic flow and extensional fracturing, single-rock falling, and wedge sliding. The single-rock falling and compressional shear and sliding are dominant failure modes in Guilin.
引文
[1] 陶琦,李强,侯艳波.让美景远离险境——广西旅游景区地质灾害隐患专项排查整治观察[J].南方国土资源,2015,(4):13-15.TAO Qi,LI Qiang,HOU Yanbo.Let beautiful scenery far away from danger-special investigation and regulation observation of geological disaster hidden danger in Guangxi scenic spot[J].Land and Resources of Southern China,2015,(4):13-15.(in Chinese)
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[4] 谢廷勇,张桂林,张紫峰.桂林穿山公园西侧危岩体破坏机制及治理[J].矿产与地质,2015,29(2):243-246.XIE Tingyong,ZHANG Guilin,ZHANG Zifeng.Failure mechanism and treatment of the dangerous rock bodies in the west of Chuanshan Park in Guilin[J].Mineral Resources and Geology,2015,29(2):243-246.(in Chinese)
[5] DD2015-02活动断层与区域地壳稳定性调查评价规范[S].北京:中国地质调查局,2015.DD2015-02 Code for Active Fault and Regional Crustal Stability Assessment[S].Beijing:China Geological Survey,2015.(in Chinese)
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[8] 广西壮族自治区地质矿产局.1/5万桂林幅区域地质调查报告[R].广西:广西壮族自治区地质矿产局,1990.Bureau of Geology and Mineral of Guangxi Zhuang Autonomous Region.The Investigation Report of Regional Geological in Guilin(1:50000) [R].Guangxi:Bureau of Geology and Mineral of Guangxi Zhuang Autonomous Region,1990.(in Chinese)
[9] 广西壮族自治区地质矿产局.桂林市地质系列图集[M].广西:广西壮族自治区地质矿产局,1988.Bureau of Geology and Mineral of Guangxi Zhuang Autonomous Region.Atlas of Geology in Guilin[M].Guangxi:Bureau of Geology and Mineral of Guangxi Zhuang Autonomous Region,1988.(in Chinese)
[10] 国土资源部.县(市)地质灾害调查与区划基本要求[Z].北京:国土资源部,2006.Ministry of Land and Resources of the People's Republic of China.Geological Hazards Investigating and Zoning of Counties and Cities[Z].Beijing:Ministry of Land and Resources of the People's Republic of China,2006.(in Chinese)
[11] Hoek E,Bray J.Rock slope engineering[J].Engineering Geology,1981,9(1):92-93.
[12] Goodman,Richard E.Introduction to Rock Mechanics,2nd ED [M].New York:John Wiley & Sons,1989.
[13] 胡厚田.崩塌分类的初步探讨[J].铁道学报,1985,7(2):90-100.HU Houtian.Preliminary investigation on the classification of landfalls[J].Journal of The China Railway Society,1985,7(2):90-100.(in Chinese)
[14] 刘宝臣,潘宗源,郑金.桂林市喀斯特危岩体发育特征及稳定性分析[J].自然灾害学报,2013,22(1):183-189.LIU Baochen,PAN Zongyuan,ZHENG Jin.Development characteristics and stability analysis of karst dangerous rock mass in Guilin City[J].Journal of Natural Disasters,2013,22(1):183-189.(in Chinese)
[15] Goodman R E,Kieffer D S.Behavior of rock in slopes[J].Journal of Geotechnical & Geoenvironmental Engineering,2000,126(8):675-684.
[16] 刘传正.重庆武隆鸡尾山形成与崩塌成因分析[J].工程地质学报,2010,18(3):297-304.LIU Chuanzheng.Mechanism analysis on the Jiweishan rockfall disaster happened in Wulong,Chongqing[J].Journal of Engineering Geology,2010,18(3):297-304.(in Chinese)
[17] 陈洪凯,王蓉,唐红梅.危岩研究现状及趋势综述[J].重庆交通学院学报,2003,22(3):18-22.CHEN Hongkai,WANG Rong,TANG Hongmei.Review on current situation to study and trend of dangerous rock mass [J].Journal of Chongqing Jiaotong University,2003,22(3):18-22.(in Chinese)
[18] Zheng D,Frost J D,Huang R Q,et al.Failure process and modes of rockfall induced by underground mining:A case study of Kaiyang Phosphorite Mine rockfalls[J].Engineering Geology,2015,197:145-157.
[19] 叶万军,董西好,杨更社,等.倾倒型黄土崩塌稳定性判据及其影响范围研究[J].岩土力学,2013,34(S2):242-246,251.YE Wanjun,DONG Xihao,YANG Gengshe,et al.Stability criterion and influencing zone of loess collapse with toppling style[J].Rock and Soil Mechanics,2013,34(S2):242-246,251.(in Chinese)
[20] 何潇,陈洪凯,唐红梅,等.长江三峡灰岩区危岩形成机理及稳定性分析研究[J].西南大学学报(自然科学版),2014,36(6):155-160.HE Xiao,CHEN Hongkai,TANG Hongmei,et al.Research on the mechanism of the development of unstable rocks in the limestone area in the Three Gorges and stability analysis for the rocks[J].Journal of Southwest University (Natural Science Edition),2014,36(6):155-160.(in Chinese)
[21] 赵鹏,李清,何潇,等.三峡库区高陡危岩软弱基座力学特性研究——以望霞危岩炭质页岩基座为例[J].自然灾害学报,2017,26(5):191-197.ZHAO Peng,LI Qing,HE Xiao,et al.Research on soft foundation mechanical properties of unstable rock on steep slope in Three Gorges Reservoir area:A case study in Wangxia[J].Journal of Natural Disasters,2017,26(5):191-197.(in Chinese)
[22] 何思为,胡官通.桂林野狗山滑坡分析[J].桂林冶金地质学院学报,1987,7(3):207-210.HE Siwei,HU Guantong.An analysis of wild dog mountain slide in Guilin[J].Journal of Guilin University of Geology,1987,7(3):207-210.(in Chinese)
[23] Luckman B H.Rockfalls and rockfall inventory data:Some observations from surprise valley,Jasper National Park,Canada[J].Earth Surface Processes & Landforms,2010,1(3):287-298.
[24] Guzzetti F,Reichenbach P,Wieczorek G F.Rockfall hazard and risk assessment in the Yosemite Valley,California,USA[J].Natural Hazards & Earth System Sciences,2003,3(6):491-503.
[25] 胡玉凤,陈筠,谢兴能,等.贵州崩塌发育特征分析[J].贵州大学学报(自然科学版),2014,31(2):40-44.HU Yufeng,CHEN Jun,XIE Xingneng,et al.Analysis of collapse development characteristics in Guizhou[J].Journal of Guizhou University(Natural Sciences),2014 ,31(2):40-44.(in Chinese)
[26] 刘传正.中国崩塌滑坡泥石流灾害成因类型[J].地质论评,2014,60(4):858-868.LIU Chuanzheng.Genetic types of landslide and debris flow disasters in China[J].Geological Review,2014,60(4):858-868.(in Chinese)
[27] Peng J,Fan Z,Wu D,et al.Heavy rainfall triggered loess–mudstone landslide and subsequent debris flow in Tianshui,China[J].Engineering Geology,2015,186(24):79-90.
[28] 张江伟,李小军,迟明杰,等.滑坡灾害的成因机制及其特征分析[J].自然灾害学报,2015,24(6):42-49.ZHANG Jiangwei,LI Xiaojun,CHI Mingjie,et al.Analysis of formation mechanism and characteristics of landslide disasters[J].Journal of Natural Disasters,2015,24(6):42-49.(in Chinese)
[2] 覃兰丽,曾宪斌,张云良.桂林市岩溶区典型地质灾害危险性评估[J].地质灾害与环境保护,2009,20(3):28-33.QIN Lanli,ZENG Xianbin,ZHANG Yunliang.Hazard evaluation of typical geological disasters in Karst area in Guilin[J].Journal of Geological Hazards and Environment Preservation,2009,20(3):28-33.(in Chinese)
[3] 刘宝臣,郑金,向志坤.桂林市屏风山西侧危岩成因及稳定性分析[J].地质灾害与环境保护,2012,23(2):60-64.LIU Baochen,ZHENG Jin,XIANG Zhikun.Formation and stability of unstable rocks at the west slope of screen mount in Guilin city[J].Journal of Geological Hazards and Environment Preservation,2012,23(2):60-64.(in Chinese)
[4] 谢廷勇,张桂林,张紫峰.桂林穿山公园西侧危岩体破坏机制及治理[J].矿产与地质,2015,29(2):243-246.XIE Tingyong,ZHANG Guilin,ZHANG Zifeng.Failure mechanism and treatment of the dangerous rock bodies in the west of Chuanshan Park in Guilin[J].Mineral Resources and Geology,2015,29(2):243-246.(in Chinese)
[5] DD2015-02活动断层与区域地壳稳定性调查评价规范[S].北京:中国地质调查局,2015.DD2015-02 Code for Active Fault and Regional Crustal Stability Assessment[S].Beijing:China Geological Survey,2015.(in Chinese)
[6] 袁道先.中国岩溶学[M].北京:地质出版社,1993.YUAN Daoxian.Chinese Karst Science[M].Beijing:Geological Publishing House,1993.(in Chinese)
[7] 冯佐海,梁金城,李晓峰,等.桂林市岩溶塌陷成因类型与时空分布特征[J].自然灾害学报,2001,10(3):92-97.FENG Zuohai,LIANG Jincheng,LI Xiaofeng,et al.Genetic types and distributive characters of Karst collapses in Guilin[J].Journal of Natural Disasters,2001,10(3):92-97.(in Chinese)
[8] 广西壮族自治区地质矿产局.1/5万桂林幅区域地质调查报告[R].广西:广西壮族自治区地质矿产局,1990.Bureau of Geology and Mineral of Guangxi Zhuang Autonomous Region.The Investigation Report of Regional Geological in Guilin(1:50000) [R].Guangxi:Bureau of Geology and Mineral of Guangxi Zhuang Autonomous Region,1990.(in Chinese)
[9] 广西壮族自治区地质矿产局.桂林市地质系列图集[M].广西:广西壮族自治区地质矿产局,1988.Bureau of Geology and Mineral of Guangxi Zhuang Autonomous Region.Atlas of Geology in Guilin[M].Guangxi:Bureau of Geology and Mineral of Guangxi Zhuang Autonomous Region,1988.(in Chinese)
[10] 国土资源部.县(市)地质灾害调查与区划基本要求[Z].北京:国土资源部,2006.Ministry of Land and Resources of the People's Republic of China.Geological Hazards Investigating and Zoning of Counties and Cities[Z].Beijing:Ministry of Land and Resources of the People's Republic of China,2006.(in Chinese)
[11] Hoek E,Bray J.Rock slope engineering[J].Engineering Geology,1981,9(1):92-93.
[12] Goodman,Richard E.Introduction to Rock Mechanics,2nd ED [M].New York:John Wiley & Sons,1989.
[13] 胡厚田.崩塌分类的初步探讨[J].铁道学报,1985,7(2):90-100.HU Houtian.Preliminary investigation on the classification of landfalls[J].Journal of The China Railway Society,1985,7(2):90-100.(in Chinese)
[14] 刘宝臣,潘宗源,郑金.桂林市喀斯特危岩体发育特征及稳定性分析[J].自然灾害学报,2013,22(1):183-189.LIU Baochen,PAN Zongyuan,ZHENG Jin.Development characteristics and stability analysis of karst dangerous rock mass in Guilin City[J].Journal of Natural Disasters,2013,22(1):183-189.(in Chinese)
[15] Goodman R E,Kieffer D S.Behavior of rock in slopes[J].Journal of Geotechnical & Geoenvironmental Engineering,2000,126(8):675-684.
[16] 刘传正.重庆武隆鸡尾山形成与崩塌成因分析[J].工程地质学报,2010,18(3):297-304.LIU Chuanzheng.Mechanism analysis on the Jiweishan rockfall disaster happened in Wulong,Chongqing[J].Journal of Engineering Geology,2010,18(3):297-304.(in Chinese)
[17] 陈洪凯,王蓉,唐红梅.危岩研究现状及趋势综述[J].重庆交通学院学报,2003,22(3):18-22.CHEN Hongkai,WANG Rong,TANG Hongmei.Review on current situation to study and trend of dangerous rock mass [J].Journal of Chongqing Jiaotong University,2003,22(3):18-22.(in Chinese)
[18] Zheng D,Frost J D,Huang R Q,et al.Failure process and modes of rockfall induced by underground mining:A case study of Kaiyang Phosphorite Mine rockfalls[J].Engineering Geology,2015,197:145-157.
[19] 叶万军,董西好,杨更社,等.倾倒型黄土崩塌稳定性判据及其影响范围研究[J].岩土力学,2013,34(S2):242-246,251.YE Wanjun,DONG Xihao,YANG Gengshe,et al.Stability criterion and influencing zone of loess collapse with toppling style[J].Rock and Soil Mechanics,2013,34(S2):242-246,251.(in Chinese)
[20] 何潇,陈洪凯,唐红梅,等.长江三峡灰岩区危岩形成机理及稳定性分析研究[J].西南大学学报(自然科学版),2014,36(6):155-160.HE Xiao,CHEN Hongkai,TANG Hongmei,et al.Research on the mechanism of the development of unstable rocks in the limestone area in the Three Gorges and stability analysis for the rocks[J].Journal of Southwest University (Natural Science Edition),2014,36(6):155-160.(in Chinese)
[21] 赵鹏,李清,何潇,等.三峡库区高陡危岩软弱基座力学特性研究——以望霞危岩炭质页岩基座为例[J].自然灾害学报,2017,26(5):191-197.ZHAO Peng,LI Qing,HE Xiao,et al.Research on soft foundation mechanical properties of unstable rock on steep slope in Three Gorges Reservoir area:A case study in Wangxia[J].Journal of Natural Disasters,2017,26(5):191-197.(in Chinese)
[22] 何思为,胡官通.桂林野狗山滑坡分析[J].桂林冶金地质学院学报,1987,7(3):207-210.HE Siwei,HU Guantong.An analysis of wild dog mountain slide in Guilin[J].Journal of Guilin University of Geology,1987,7(3):207-210.(in Chinese)
[23] Luckman B H.Rockfalls and rockfall inventory data:Some observations from surprise valley,Jasper National Park,Canada[J].Earth Surface Processes & Landforms,2010,1(3):287-298.
[24] Guzzetti F,Reichenbach P,Wieczorek G F.Rockfall hazard and risk assessment in the Yosemite Valley,California,USA[J].Natural Hazards & Earth System Sciences,2003,3(6):491-503.
[25] 胡玉凤,陈筠,谢兴能,等.贵州崩塌发育特征分析[J].贵州大学学报(自然科学版),2014,31(2):40-44.HU Yufeng,CHEN Jun,XIE Xingneng,et al.Analysis of collapse development characteristics in Guizhou[J].Journal of Guizhou University(Natural Sciences),2014 ,31(2):40-44.(in Chinese)
[26] 刘传正.中国崩塌滑坡泥石流灾害成因类型[J].地质论评,2014,60(4):858-868.LIU Chuanzheng.Genetic types of landslide and debris flow disasters in China[J].Geological Review,2014,60(4):858-868.(in Chinese)
[27] Peng J,Fan Z,Wu D,et al.Heavy rainfall triggered loess–mudstone landslide and subsequent debris flow in Tianshui,China[J].Engineering Geology,2015,186(24):79-90.
[28] 张江伟,李小军,迟明杰,等.滑坡灾害的成因机制及其特征分析[J].自然灾害学报,2015,24(6):42-49.ZHANG Jiangwei,LI Xiaojun,CHI Mingjie,et al.Analysis of formation mechanism and characteristics of landslide disasters[J].Journal of Natural Disasters,2015,24(6):42-49.(in Chinese)