摘要
岩质滑坡通常受控于一系列与断层、褶皱和剪切带等相关的复杂岩体构造损伤面和软弱带,为滑坡启动提供了潜在破坏边界。为研究断裂与背斜构造背景下岩体损伤和不连续地质界面对滑坡三维边界形成和启动模式的影响,选择2008年汶川Ms8.0级特大地震在大水闸背斜两翼碳酸盐岩地层触发的4处大型滑坡为实例,开展了详细的工程地质调查、结构面测量、岩体强度测试及GSI岩体质量评价。结果表明:断裂活动与背斜演化导致的构造损伤差异显著,岩体质量从背斜轴部向两翼总体呈逐渐增加趋势,仅局部显著降低,并对滑坡的启动位置有着重要控制作用;同时,构造损伤背景下,特定岩体结构面与构造软弱带共同控制着滑坡启动机制,并将控制类型归纳为"控制侧滑型"、"控制底滑型"、"控制滑体型"及"控制基座型";此外,地震滑坡与非地震滑坡的GSI对比表明,强震可能通过降低岩体质量条件促使滑坡快速启动,进而加快构造损伤区的地貌侵蚀过程。考虑复杂构造环境岩体损伤对评估强震潜在大型滑坡发生位置、启动机制和模式有重要作用。
Rock landslides are generally controlled by a series of discontinuities that relate to faults,folds and shear zones,which provide potential failure boundaries.To study the influences of rock mass damage and discontinuous geological interface on the formation and initiation of landslides under the background of fault and anticline,four large landslides triggered by the Wenchuan Ms8.0 earthquake in the carbonate strata of two wings of Dashuizha anticline are selected as examples to carry out detailed engineering geological investigation,structural plane survey,rock testing and rock quality assessment of GSI.The results show that there are clear differences in structural damage caused by fault and anticline.Gradually,the rock mass quality increases from the axis of anticline to the two wings,only decreases significantly locally,and controls the formation position of landslides.Meanwhile,under the background of structural damage,the structural plane and weak zone of specific rock jointly determine the initiation mechanism,and the types are summarized as"control side sliding type","control bottom sliding type","control sliding body type"and"control base type".In addition,the comparison of GSI of seismic and non-seismic landslides reveals that strong earthquake may promote the rapid start of landslides by reducing the rock mass quality,and then accelerate the process of geomorphic erosion in the structural damage area.Finally,it is believed that considering the rock mass damage in complex tectonic environment is very important to assess the location and initiation mechanism of potential large-scale landslides caused by strong earthquakes.
作者
梁靖
崔圣华
裴向军
黄润秋
LIANG Jing;CUI Sheng-hua;PEI Xiang-jun;HUANG Run-qiu(State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059,China;No.405 Geological Party,Sichuan Bureau of Geology and Mineral Exploration and Development,Chengdu 611800,China)
出处
《岩土工程学报》
EI
CAS
CSCD
北大核心
2021年第6期1039-1049,共11页
Chinese Journal of Geotechnical Engineering
基金
国家重点研发计划项目(2017YFC1501002)
国家自然科学基金项目(41907254,41931296)
四川省重点研发计划项目(2019YFG0460)。
关键词
地震滑坡
GSI
构造损伤
岩体质量
构造软弱带
启动机制
earthquake-induced landslide
GSI
structural damage
rock mass quality
structural weak zone
initiation mechanism
