唐家山滑坡变形运动机制的离散元模拟
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摘要
地震是滑坡灾害的一个重要触发因素,而这类形式的滑坡通常危害较大。以汶川地震触发的唐家山滑坡为例,在野外现场调查基础上,采用离散元数值模拟技术,对滑坡由变形累积到破坏滑动的全过程进行模拟,以研究地震作用下顺层岩质滑坡的变形破坏过程。结果表明:在地震力及滑体重力作用下,坡顶首先形成应力集中,滑体沿中后部的软弱面产生蠕变变形,随着持续的地震动力输入,应力不断向中前部的锁固段集中,使得变形沿接触面不断向坡脚方向扩展,最终从坡脚剪出,破裂面贯通形成滑带;通过滑动过程模拟表明,唐家山滑坡运动模式为:启动→高速滑动→碰撞停积→自稳过程,滑坡滑动过程中,斜坡表层部分块体在地震水平力作用下发生临空抛射现象,表层岩体在滑动过程中,受地震竖向作用力而发生垂直抛落现象;地震力作用下坡体中质点加速度、速度具有高程放大效应,表现为水平加速度放大系数大于竖向加速度放大系数、水平速度放大系数大于竖向速度放大系数,对比结构面监测点和基岩监测点加速度、速度放大系数,表明滑坡启动时具有较大的加速度,也说明不连续结构面对岩质边坡的动力反应起着控制性作用。
Earthquake is considered as one of the main factors of the generation of a landslide which always causes severe disasters.Taking Tangjiashan landslide,a typical bedding rockslide triggered by the Ms 8.0 Wenchuan earthquake,as the study site,and discrete element numerical simulation is carried out to simulate the initial and subsequent movement of the rockslide.It is found that under seismic loading,stress concentration occurred first at the top of the slope and then expanded from the top towards the toe along the sliding plane,sheared out from the toe in the end and resulting in failure of the slope.The simulation of the subsequent movement of the slope shows that the movement mode of Tangjiashan landslide is starting-up→high-speed sliding→colliding down→self-stabilizing.It also shows that some blocks of the surface exhibit horizontal throwing and vertical jumping under seismic loading.Topographic amplification effects are also observed from both acceleration and velocity of the monitoring points of the slope,indicating that the amplification factor of horizontal acceleration exceeds that of vertical acceleration,and the amplification factor of horizontal velocity exceeds that of vertical velocity.By contrasting the amplification effect of structural plane and the underlying bedrock,it is found that there was a high acceleration when the landslide was at the stage of starting-up,and it also shows that the existence of persistent structural plane plays a controlling role in the dynamic response of the rock slope.
Earthquake is considered as one of the main factors of the generation of a landslide which always causes severe disasters.Taking Tangjiashan landslide,a typical bedding rockslide triggered by the Ms 8.0 Wenchuan earthquake,as the study site,and discrete element numerical simulation is carried out to simulate the initial and subsequent movement of the rockslide.It is found that under seismic loading,stress concentration occurred first at the top of the slope and then expanded from the top towards the toe along the sliding plane,sheared out from the toe in the end and resulting in failure of the slope.The simulation of the subsequent movement of the slope shows that the movement mode of Tangjiashan landslide is starting-up→high-speed sliding→colliding down→self-stabilizing.It also shows that some blocks of the surface exhibit horizontal throwing and vertical jumping under seismic loading.Topographic amplification effects are also observed from both acceleration and velocity of the monitoring points of the slope,indicating that the amplification factor of horizontal acceleration exceeds that of vertical acceleration,and the amplification factor of horizontal velocity exceeds that of vertical velocity.By contrasting the amplification effect of structural plane and the underlying bedrock,it is found that there was a high acceleration when the landslide was at the stage of starting-up,and it also shows that the existence of persistent structural plane plays a controlling role in the dynamic response of the rock slope.
引文
[1]王来贵,赵娜,李天斌.强震诱发单一弱面斜坡塌滑有限元模拟[J].岩石力学与工程学报,2009,28(增1):3 163-3 167.(WANG Laigui,ZHAO Na,LI Tianbin.Finite element simulation of collapse and sliding of slope with single weak plane induced by strong earthquake[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(Supp.1):3 163-3 167.(in Chinese))
[2]冯文凯,许强,黄润秋.斜坡震裂变形力学机制初探[J].岩石力学与工程学报,2009,28(增1):3 124-3 130.(FENG Wenkai,XU Qiang,HUANG Runqiu.Preliminary study on mechanical mechanism of slope earthquake-induced deformation[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(Supp.1):3 124-3 130.(in Chinese))
[3]唐春安,左宇军,秦洒凤,等.汶川地震中的边坡浅层碎裂与抛射模式及其动力学解释[C]//汶川大地震工程震害调查分析与研究.[S.l.]:[s.n.],2009:258-262.(TANG Chun′an,ZUO Yujun,QIN Safeng,et al.Slope shallow chipped and aerosol propellant mode and its dynamics explanation in Wenchuan earthquake[C]//Wenchuan Earthquake Engineering Disaster Investigation Analysis and Research.[S.l.]:[s.n.],2009:258-262.(in Chinese))
[4]郑颖人,叶海林,黄润秋.地震边坡破坏机制及其破裂面的分析探讨[J].岩石力学与工程学报,2009,28(8):1 714-1 723.(ZHENG Yingren,YE Hailin,HUANG Runqiu.Analysis and discussion of failure mechanism and fracture surface of slope under earthquake[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(8):1 714-1 723.(in Chinese))
[5]毕忠伟,张明,金峰,等.地震作用下边坡的动态响应规律研究[J].岩土力学,2009,30(增1):180-183.(BI Zhongwei,ZHANG Ming,JIN Feng,et al.Dynamic response of slopes under earthquakes[J].Rock and Soil Mechanics,2009,30(Supp.1):180-183.(in Chinese))
[6]佟海宁,姚令侃.松散堆积体边坡地震成灾模式与防治对策[J].路基工程,2009,(6):26-27.(TONG Haining,YAO Lingkan.Earthquake flood-gates mode and control countermeasures of loose stained slope[J].Subgrade Engineering,2009,(6):26-27.(in Chinese))
[7]薄景山,齐文浩,刘红帅,等.汶川特大地震汉源烈度异常原因的初步分析[J].地震工程与工程振动,2009,29(6):53-64.(BO Jingshan,QI Wenhao,LIU Hongshuai,et al.Abnormality of seismic intensity in Hanyuan during Wenchuan earthquake[J].Journal of Earthquake Engineering and Engineering Vibration,2009,29(6):53-64.(in Chinese))
[8]杨庆华,姚令侃,杨明.地震作用下松散堆积体崩塌的颗粒流数值模拟[J].西南交通大学学报,2009,44(4):580-584.(YANG Qinghua,YAO Lingkan,YANG Ming.Particle flow numerical simulation of landslip of loose slope under seismic loading[J].Journal of Southwest Jiaotong University,2009,44(4):580-584.(in Chinese))
[9]BARDET J P,SCOTT R F.Seismic stability of fracture rock masses with the distinct element method[C]//Proceedings of the 26th U.S.Symposium on Rock Mechanics(USRMS).Rotterdam:A.A.Balkema,1985:139-149.
[10]ZHANG C H,PEKAU O A,JIN F,et al.Application of distinct element method in dynamic analysis of high rock slopes and blocky structures[J].Soil Dynamics and Earthquake Engineering,1997,16(6):385-394.
[11]胡卸文,黄润秋,施裕兵,等.唐家山滑坡堵江机制及堰塞坝溃坝模式分析[J].岩石力学与工程学报,2009,28(1):181-189.(HU Xiewen,HUANG Runqiu,SHI Yubing,et al.Analysis of blocking river mechanism of Tangjiashan landslide and dam-breaking mode of its barrier dam[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(1):181-189.(in Chinese))
[12]Itasca Consulting Group Inc..Universal distinct element code(version 4.0)user′s guide[R].Minneapolis:Itasca Consulting Group,Inc.,2004.
[13]崔芳鹏.地震P-S波时差耦合作用的斜坡崩滑效应研究[博士学位论文][D].北京:中国科学院地质与地球物理研究所,2009.(CUI Fangpeng.Study on collapsing and sliding response of slope triggered by single and combined action with time difference of p and s seismic waves[Ph.D.Thesis][D].Beijing:Institute of Geology and Geophysics,Chinese Academy of Sciences,2009.(in Chinese))
[14]崔芳鹏,胡瑞林,殷跃平,等.纵横波时差耦合作用的斜坡崩滑效应离散元分析——以北川唐家山滑坡为例[J].岩石力学与工程学报,2010,29(2):319-327.(CUI Fangpeng,HU Ruilin,YIN Yueping,et al.Discrete element analysis of collapsing and sliding response of slope triggered by time difference coupling effects of P and S seismic waves—taking Tangjiashan landslide in Beichuan County for example[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(2):319-327.(in Chinese))
[15]KUHLEMEYER R L,LYSMER J.Finite element method accuracy for wave propagation problems[J].Journal of the Soil Mechanics and Foundations Division,ASCE,1973,99(5):421-417.
[16]许强,黄润秋.5.12汶川大地震诱发大型崩滑灾害动力特征初探.工程地质学报,2008,16(6):721-729.(XU Qiang,HUANG Runqiu.Kinetics characteristics of large landslides triggered by May 12th Wenchuan earthquake[J].Journal of Engineering Geology,2008,16(6):721-729.(in Chinese))
[2]冯文凯,许强,黄润秋.斜坡震裂变形力学机制初探[J].岩石力学与工程学报,2009,28(增1):3 124-3 130.(FENG Wenkai,XU Qiang,HUANG Runqiu.Preliminary study on mechanical mechanism of slope earthquake-induced deformation[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(Supp.1):3 124-3 130.(in Chinese))
[3]唐春安,左宇军,秦洒凤,等.汶川地震中的边坡浅层碎裂与抛射模式及其动力学解释[C]//汶川大地震工程震害调查分析与研究.[S.l.]:[s.n.],2009:258-262.(TANG Chun′an,ZUO Yujun,QIN Safeng,et al.Slope shallow chipped and aerosol propellant mode and its dynamics explanation in Wenchuan earthquake[C]//Wenchuan Earthquake Engineering Disaster Investigation Analysis and Research.[S.l.]:[s.n.],2009:258-262.(in Chinese))
[4]郑颖人,叶海林,黄润秋.地震边坡破坏机制及其破裂面的分析探讨[J].岩石力学与工程学报,2009,28(8):1 714-1 723.(ZHENG Yingren,YE Hailin,HUANG Runqiu.Analysis and discussion of failure mechanism and fracture surface of slope under earthquake[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(8):1 714-1 723.(in Chinese))
[5]毕忠伟,张明,金峰,等.地震作用下边坡的动态响应规律研究[J].岩土力学,2009,30(增1):180-183.(BI Zhongwei,ZHANG Ming,JIN Feng,et al.Dynamic response of slopes under earthquakes[J].Rock and Soil Mechanics,2009,30(Supp.1):180-183.(in Chinese))
[6]佟海宁,姚令侃.松散堆积体边坡地震成灾模式与防治对策[J].路基工程,2009,(6):26-27.(TONG Haining,YAO Lingkan.Earthquake flood-gates mode and control countermeasures of loose stained slope[J].Subgrade Engineering,2009,(6):26-27.(in Chinese))
[7]薄景山,齐文浩,刘红帅,等.汶川特大地震汉源烈度异常原因的初步分析[J].地震工程与工程振动,2009,29(6):53-64.(BO Jingshan,QI Wenhao,LIU Hongshuai,et al.Abnormality of seismic intensity in Hanyuan during Wenchuan earthquake[J].Journal of Earthquake Engineering and Engineering Vibration,2009,29(6):53-64.(in Chinese))
[8]杨庆华,姚令侃,杨明.地震作用下松散堆积体崩塌的颗粒流数值模拟[J].西南交通大学学报,2009,44(4):580-584.(YANG Qinghua,YAO Lingkan,YANG Ming.Particle flow numerical simulation of landslip of loose slope under seismic loading[J].Journal of Southwest Jiaotong University,2009,44(4):580-584.(in Chinese))
[9]BARDET J P,SCOTT R F.Seismic stability of fracture rock masses with the distinct element method[C]//Proceedings of the 26th U.S.Symposium on Rock Mechanics(USRMS).Rotterdam:A.A.Balkema,1985:139-149.
[10]ZHANG C H,PEKAU O A,JIN F,et al.Application of distinct element method in dynamic analysis of high rock slopes and blocky structures[J].Soil Dynamics and Earthquake Engineering,1997,16(6):385-394.
[11]胡卸文,黄润秋,施裕兵,等.唐家山滑坡堵江机制及堰塞坝溃坝模式分析[J].岩石力学与工程学报,2009,28(1):181-189.(HU Xiewen,HUANG Runqiu,SHI Yubing,et al.Analysis of blocking river mechanism of Tangjiashan landslide and dam-breaking mode of its barrier dam[J].Chinese Journal of Rock Mechanics and Engineering,2009,28(1):181-189.(in Chinese))
[12]Itasca Consulting Group Inc..Universal distinct element code(version 4.0)user′s guide[R].Minneapolis:Itasca Consulting Group,Inc.,2004.
[13]崔芳鹏.地震P-S波时差耦合作用的斜坡崩滑效应研究[博士学位论文][D].北京:中国科学院地质与地球物理研究所,2009.(CUI Fangpeng.Study on collapsing and sliding response of slope triggered by single and combined action with time difference of p and s seismic waves[Ph.D.Thesis][D].Beijing:Institute of Geology and Geophysics,Chinese Academy of Sciences,2009.(in Chinese))
[14]崔芳鹏,胡瑞林,殷跃平,等.纵横波时差耦合作用的斜坡崩滑效应离散元分析——以北川唐家山滑坡为例[J].岩石力学与工程学报,2010,29(2):319-327.(CUI Fangpeng,HU Ruilin,YIN Yueping,et al.Discrete element analysis of collapsing and sliding response of slope triggered by time difference coupling effects of P and S seismic waves—taking Tangjiashan landslide in Beichuan County for example[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(2):319-327.(in Chinese))
[15]KUHLEMEYER R L,LYSMER J.Finite element method accuracy for wave propagation problems[J].Journal of the Soil Mechanics and Foundations Division,ASCE,1973,99(5):421-417.
[16]许强,黄润秋.5.12汶川大地震诱发大型崩滑灾害动力特征初探.工程地质学报,2008,16(6):721-729.(XU Qiang,HUANG Runqiu.Kinetics characteristics of large landslides triggered by May 12th Wenchuan earthquake[J].Journal of Engineering Geology,2008,16(6):721-729.(in Chinese))
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