青川刨地里地震滑坡发育特征及其成因机制探讨  

Analysis of characteristics and failure mechanism of Paodili seismic landslide in Qingchuan County

作　　者：李均益 罗永红[1,2] 周赞 南凯 Li Junyi;Luo Yonghong;Zhou Zan;Nan Kai(College of Environment and Civil Engineering,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]成都理工大学环境与土木工程学院,成都610059 [2]成都理工大学地质灾害防治与地质环境保护国家重点实验室,成都610059

出　　处：《地震学报》2024年第3期514-525,共12页Acta Seismologica Sinica

基　　金：国家自然科学基金面上项目(42077257);地质灾害防治与地质环境保护国家重点实验室开放基金(SKLGP2019K024)联合资助。

摘　　要：以“5·12”汶川地震诱发的青川县刨地里滑坡为例,现场调查了滑坡的地质特征,并基于离散元软件(UDEC)分析了1号滑坡动力响应及变形破坏过程,探讨了滑坡的成因机制。现场调查表明,刨地里1号滑坡具有近水平“上硬下软”的地层结构,其中石坎断层穿过了滑坡后缘;滑坡堆积体的岩性分带特征表明,刨地里1号滑坡下部千枚岩先于上部硅质岩被破坏,且破坏时间早于2号和3号滑坡;数值模拟研究揭示,峰值加速度放大效应在断层带附近的千枚岩内最强,其放大系数达6.79,导致下层千枚岩首先沿陡倾面产生拉裂破坏,随后上层硅质岩体产生拉裂破坏,结果与现场调查堆积物特征较吻合;断层和上硬下软的地层结构对刨地里滑坡动力响应、变形及破坏起到了控制作用。该研究可为上硬下软且含断层的地震滑坡的评价提供参考。The problem of slope stability in high-intensity mountainous area is prominent.It is of great significance to study the relationship between geological structure and strata structure and the triggering mechanism of landslide under earthquake action.In this paper,the geological characteristics of the landslide in Qingchuan County are investigated,and the dynamic response and deformation and failure process of the 1st landslide are analyzed based on discrete element software(UDEC).The field investigation shows that the slope of Paodili 1st landslide has a near-horizontal “upper-hard,lower-soft” stratigraphic texture,in which faults pass through the back edge of the slope.The lithologic zonation of landslide deposits shows that the lower phyllite of Paodili 1st landslide was destroyed earlier than the upper siliceous rock,and the broken time was earlier than the 2nd and 3rd landslides.The numerical simulation research reveals that the peak acceleration amplification effect is strongest in phyllite near the fault zone,with an amplification factor of 6.79.This leads to the lower phyllite first experienced tensile failure along the steep dip surface,then the upper siliceous rock mass produced tension failure.The results are in good agreement with the characteristics of the deposits in the field investigation.The dynamic response,deformation,and failure of the landslide are controlled by the fault and the upper-hard,lower soft stratigraphic texture.This study can provide a reference for seismic landslides evaluation in regions characterized by faulting and “upper-hard,lower-soft” strata.

关 键 词：“5·12”汶川地震 地震滑坡 上硬下软地层 石坎断层 成因机制 

分 类 号：P315.9[天文地球—地震学]