摘要
大光包滑坡(12×108 m3)是2008年汶川Ms8.0级地震触发的最大滑坡。地震记录表明,滑坡区不仅遭受了强烈水平地震动,而且受到与之几乎相等的垂直地震动。采用考虑垂直地震力的改进Newmark模型,开展滑面抗剪强度参数影响下滑坡地震永久位移响应研究。结果表明,垂直地震动显著增大了滑坡地震累积永久位移(最大增幅达903%),同时垂直地震动对永久位移(累积总量和累积速率)贡献受到滑面内摩擦角的显著影响(影响幅度达87.8%~90.7%),而受黏聚力影响较小(影响幅度仅为5%~27.4%);地震过程滑坡永久位移最大累积速率发生时刻和时长决定于地震能量集中释放时段,大光包滑坡区120 s地震持时内,50%能量在30~50 s内集中释放,由此推测大光包滑坡失稳可能在地震初期。研究所采用的改进Newmark法可用于评价垂直地震动对地震滑坡启动的贡献。
The Daguangbao landslide(12×108 m3)is the largest landslide triggered by the Wenchuan Ms8.0 magnitude earthquake in 2008.The seismic records show that the landslide area not only suffered strong horizontal ground motions,but also received almost equal vertical ground motions.In this paper,an improved Newmark model considering vertical seismic force is used to study the influence of the shear strength parameters of the sliding surface on the earthquake permanent displacement response of the landslide.The results show that vertical ground motions increase the cumulative permanent displacement of the landslide(the maximum increase is 903%),and the contribution of vertical ground motion to the permanent displacement(cumulative total amount and cumulative rate)is significantly affected by the friction angle of the sliding surface(the influence level ranges from 87.8%to 90.7%),but is less affected by cohesion(the influence range is only 5%-27.4%).The maximum cumulative rate and duration of the permanent displacement of the landslide during the seismic process are determined by the concentrated release period of the seismic energy,and 50%of the energy is released within 30-50 s during the 120 s earthquake holding time in the Daguangbao landslide area.It is inferred that the instability of Daguangbao landslide may be in the early stage of earthquake.The improved Newmark method used in this paper can be used to evaluate the contribution of vertical ground motion to the initiation of the seismic landslide.
作者
何宇航
裴向军
崔圣华
HE Yuhang;PEI Xiangjun;CUI Shenghua(State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu,Sichuan 610059,China)
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2021年第S01期2738-2749,共12页
Chinese Journal of Rock Mechanics and Engineering
基金
国家重点研发计划(2017YFC1501002)
国家自然科学基金资助项目(41907254,41931296)。
关键词
边坡工程
大光包滑坡
垂直地震加速度
NEWMARK
滑坡启动
地震滑坡
slope engineering
Daguangbao landslide
vertical seismic acceleration
Newmark
landslide initiation
seismic landslide
