贵州纳雍“8·28”崩塌破坏过程与变形破坏机理初探
|
摘要
2017年8月28日,贵州省纳雍县张家湾镇普洒村发生山体崩塌,崩塌方量约6×10~5m~3,造成35人遇难。本文通过应急调查、过程还原及工程地质分析,对崩塌破坏过程及机理初步研究,以期有益于后续防治及类似灾害防范。研究发现,崩塌主要发生在三叠系下统夜郎组灰岩和粉砂岩地层中,岩层面近水平,受构造和卸荷作用,发育有平行于坡面的陡倾节理,受长期重力作用和风化作用影响,溶蚀漏斗和塌陷发育,节理在长期的风化过程中形成裂隙带和沉陷带;崩塌过程还原显示,崩塌可分为"沉陷带变形崩塌-坡面局部崩塌-整体溃屈崩塌-撞击地面-碎屑流"五个阶段;根据崩塌变形和运动特征,崩塌可分为崩塌源区、崩积区、碎屑流区和变形区四个区;崩塌体在降雨和采矿作用影响下,拉裂沉陷带和水体的楔形侧向挤压和劈裂作用加剧了坡顶临空岩土体的变形,崩塌发生前的降雨过程对崩塌的发生有重要的促进作用。
A rock collapse with volume of about 6 × 10~5 m~3 occurred in Pusa village,Zhangjiawan Town,Nayong County,Guizhou Province on August 28,2017,causing 35 deaths. A preliminary study on the failure process and mechanism of this disaster is conducted in this paper by a series of emergency investigation,failure evolution reproducing and engineering geological analysis,aiming at a better management of the problems induced by this collapse and prevention of similar disasters in the future. This study suggests that the collapse mainly occurred in the limestone and siltstones layers which belong to the Yelang Formation of lower Trias. Due to the structural activities and unloading effects,the sub-horizontal strata have many steep joints which are parallel to the slope surface. Because of the long-term gravity and weathering effects,the corrosion funnels and subsidence are developed,and the fissure zone and subsidence area are formed. By reproducing the failure process,it is shown that the collapse can be divided into five stages as follows:( 1) deformation and collapse of the subsidence area;( 2) local collapse of the slope surface;( 3) complete collapse;( 4)impacting the ground; and( 5) formation of debris flow. According to the deformation and movement characteristics,the collapse area can be divided into four zones:( 1) the source zone,( 2) the collapsedeposits zone;( 3) the debris flow zone; and( 4) the deformation zone. Influenced by rainfall and mining activities,the deformation of the upper rock mass and soil are enhanced owing to the extension induced subsidence area as well as the lateral wedge splitting effects of the water,therefore the rainfall played an important role in the occurrence of this collapse. In addition,the risk of high-speed debris flow should be studied based on the investigation,evaluation,monitoring,warning and prevention of high collapse.
A rock collapse with volume of about 6 × 10~5 m~3 occurred in Pusa village,Zhangjiawan Town,Nayong County,Guizhou Province on August 28,2017,causing 35 deaths. A preliminary study on the failure process and mechanism of this disaster is conducted in this paper by a series of emergency investigation,failure evolution reproducing and engineering geological analysis,aiming at a better management of the problems induced by this collapse and prevention of similar disasters in the future. This study suggests that the collapse mainly occurred in the limestone and siltstones layers which belong to the Yelang Formation of lower Trias. Due to the structural activities and unloading effects,the sub-horizontal strata have many steep joints which are parallel to the slope surface. Because of the long-term gravity and weathering effects,the corrosion funnels and subsidence are developed,and the fissure zone and subsidence area are formed. By reproducing the failure process,it is shown that the collapse can be divided into five stages as follows:( 1) deformation and collapse of the subsidence area;( 2) local collapse of the slope surface;( 3) complete collapse;( 4)impacting the ground; and( 5) formation of debris flow. According to the deformation and movement characteristics,the collapse area can be divided into four zones:( 1) the source zone,( 2) the collapsedeposits zone;( 3) the debris flow zone; and( 4) the deformation zone. Influenced by rainfall and mining activities,the deformation of the upper rock mass and soil are enhanced owing to the extension induced subsidence area as well as the lateral wedge splitting effects of the water,therefore the rainfall played an important role in the occurrence of this collapse. In addition,the risk of high-speed debris flow should be studied based on the investigation,evaluation,monitoring,warning and prevention of high collapse.
引文
[1]刘传正,郭强,陈红旗.贵州省纳雍县岩脚寨危岩崩塌灾害成因初步分析[J].中国地质灾害与防治学报,2004,15(4):120-121.LIU Chuanzheng,GUO Qiang,CHEN Hongqi.Investigation of rockfall hazard at Yanjiao in Nayong of Guizhou Province[J].The Chinese Journal of Geological Hazard and Control,2004,15(4):120-121.
[2]殷跃平,朱继良,杨胜元.贵州关岭大寨高速远程滑坡-碎屑流研究[J].工程地质学报,2010,18(4):445-454.YIN Yueping,ZHU Jiliang,YANG Shengyuan.Investigation of a high speed and long run-out rockslide-debris flow at Dazhai in Guanling of Guizhou Provinve[J].Journal of Engineering Geology,2010,18(4):445-454.
[3]刘传正.贵州关岭大寨崩滑碎屑流灾害初步研究.工程地质学报[J].2010,18(5):623-630.LIU Chuanzheng.Preliminary findings on Dazhai landslide-debris flow disaster in Guizhou province[J].Journal of Engineering Geology,2010,18(5):623-630.
[4]陈泽富,孔纪名,王成华.贵州纳雍成灾机理及其避灾警示作用[J].中国地质灾害与防治学报,2006,17(3):32-35.CHEN Zefu,KONG Jiming,WANG Chenghua.Characteristics of the falling-slide type landslide in Nayong in Guizhou province and the lessons learned for disaster mitigation in other areas[J].The Chinese Journal of Geological Hazard and Control,2006,17(3):32-35.
[5]董秀军,裴向军,黄润秋.贵州凯里龙场镇山体崩塌基本特征与成因分析[J].中国地质灾害与防治学报,2015,26(3):3-9.DONG Xiujun,PEI Xiangjun,HUANG Runqiu.The Longchangzhen collapse in Kaili,Guizhou:characteristics and failure causes[J].The Chinese Journal of Geological Hazard and Control,2015,26(3):3-9.
[6]殷跃平.云南镇雄特大滑坡灾害的启示[J].中国地质灾害与防治学报,2013,24(1):Ⅰ-Ⅱ.YIN Yueping.The revelation of the Zhenxiong catastrophic landslide disaster[J].The Chinese Journal of Geological Hazard and Control,2013,24(1):Ⅰ-Ⅱ.
[7]刘传正.论地质灾害风险识别问题[J].水文地质工程地质,2017,44(4):1-7.LIU Chuanzheng.Research on the risk recognition of geological disasters[J].Hydrogeology&Engineering Geology,2017,44(4):1-7.
[2]殷跃平,朱继良,杨胜元.贵州关岭大寨高速远程滑坡-碎屑流研究[J].工程地质学报,2010,18(4):445-454.YIN Yueping,ZHU Jiliang,YANG Shengyuan.Investigation of a high speed and long run-out rockslide-debris flow at Dazhai in Guanling of Guizhou Provinve[J].Journal of Engineering Geology,2010,18(4):445-454.
[3]刘传正.贵州关岭大寨崩滑碎屑流灾害初步研究.工程地质学报[J].2010,18(5):623-630.LIU Chuanzheng.Preliminary findings on Dazhai landslide-debris flow disaster in Guizhou province[J].Journal of Engineering Geology,2010,18(5):623-630.
[4]陈泽富,孔纪名,王成华.贵州纳雍成灾机理及其避灾警示作用[J].中国地质灾害与防治学报,2006,17(3):32-35.CHEN Zefu,KONG Jiming,WANG Chenghua.Characteristics of the falling-slide type landslide in Nayong in Guizhou province and the lessons learned for disaster mitigation in other areas[J].The Chinese Journal of Geological Hazard and Control,2006,17(3):32-35.
[5]董秀军,裴向军,黄润秋.贵州凯里龙场镇山体崩塌基本特征与成因分析[J].中国地质灾害与防治学报,2015,26(3):3-9.DONG Xiujun,PEI Xiangjun,HUANG Runqiu.The Longchangzhen collapse in Kaili,Guizhou:characteristics and failure causes[J].The Chinese Journal of Geological Hazard and Control,2015,26(3):3-9.
[6]殷跃平.云南镇雄特大滑坡灾害的启示[J].中国地质灾害与防治学报,2013,24(1):Ⅰ-Ⅱ.YIN Yueping.The revelation of the Zhenxiong catastrophic landslide disaster[J].The Chinese Journal of Geological Hazard and Control,2013,24(1):Ⅰ-Ⅱ.
[7]刘传正.论地质灾害风险识别问题[J].水文地质工程地质,2017,44(4):1-7.LIU Chuanzheng.Research on the risk recognition of geological disasters[J].Hydrogeology&Engineering Geology,2017,44(4):1-7.