“6.1”芦山地震作用下宝兴新华村滑坡动力响应与失稳过程离散元模拟  

Discrete element simulation of the dynamic response and instability process of the Xinhua Village landslide in Baoxing County under the "6.1" Lushan earthquake

作　　者：周赞 罗永红[1,2] 南凯 李均益 马潇 ZHOU Zan;LUO Yonghong;NAN Kai;LI Junyi;MA Xiao(College of Environment&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：《地质科技通报》2024年第2期226-237,共12页Bulletin of Geological Science and Technology

基　　金：国家自然科学基金项目(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项目(SKLGP2019K024)。

摘　　要：斜坡浅表层是各类地震地质灾害发育的潜在破坏位置,坡面形态和坡体结构往往造成斜坡动力响应及破坏的复杂化。为探究不稳定斜坡浅表潜在滑动层动力响应特征与失稳过程,以芦山M_(s)6.1级地震触发的新华村滑坡为例,基于现场调查采用离散元方法建立了二维计算模型,分析了该斜坡潜在滑动层及坡面形态的动力响应特征并对其失稳过程进行了模拟。结果表明:(1)斜坡浅表潜在滑动层具有强烈动力放大效应;(2)微地貌对于潜在不稳定斜坡坡面的放大效应具有明显的影响,浅表潜在滑动层水平向及竖直向加速度在凸出部位的放大效应显著,凹陷部位相较于凸出部位放大效应较低;(3)研究揭示新华村滑坡在微地貌的作用下凸起地形呈现先于凹陷地形遭受破坏,其失稳过程分为震动放大局部震裂-凸出地形破坏-凹陷地形破坏-完全破坏整体下滑-重力堆积5个阶段。该研究结果有助于提升防灾人员对地震诱发潜在不稳定斜坡失稳的认识,为防灾减灾提供理论和数据支撑。[Objective] The shallow potential sliding layer of a slope is an important feature in seismic geological disasters.Its characteristics,such as slope shape and slope structure,tend to complicate the dynamic response and slope damage.[Methods] In this paper,the landslide in Xinhua Village,triggered by the Lushan M_(s) 6.1 earthquake,is taken as a case study,and two-dimensional discrete element computational models are developed based on a field investigation.The dynamic response and simulate instability are investigated by comparing numerical simulations of homogeneous and heterogeneous models,representing pure terrain and a shallow potential sliding layer,respectively.[Results] The findings are as follows:(1) The potential sliding layer at the shallow surface of the slope exhibits significant dynamic amplification,which typically increases nonlinearly with height;(2)The slope surface shape has an obvious influence on the slope amplification effect.In the convex part,the amplification effect of the horizontal and vertical acceleration of the slope surface is significant,while the amplification effect of the concave part is lower than that of the convex part;(3) In the Xinhua Village landslide,the convex terrain is destroyed before the concave terrain under the effect of micromorphology,and its instability process is divided into five stages,namely,local seismic cracking of vibration amplification,convex terrain destruction,concave terrain destruction,complete destruction of the overall slide and gravity accumulation.[Conclusion] The research results are helpful for deepening the understanding of potential unstable slopes induced by earthquakes and shedding light on disaster prevention and mitigation.

关 键 词：芦山M_(s)6.1级地震 地震滑坡 动力响应 变形破坏模型 二维离散元模拟 新华村滑坡 

分 类 号：P642.22[天文地球—工程地质学]