Parallel numerical analysis of the failure characteristics of earthquake-induced landslides
Parallel numerical analysis of the failure characteristics of earthquake-induced landslides
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DOI：
10.1007/s12303-015-0056-8
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发表时间：
2016-11
影响因子：
1.2
通讯作者：
Zhenzhen Yan;Xiaoping Du;Xiangtao Fan
中科院分区：
文献类型：
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作者：
Zhenzhen Yan;Xiaoping Du;Xiangtao Fan
地震滑坡是一种严重的自然灾害，在世界许多山区造成了巨大的人员伤亡和经济损失。然而，由于地震动力学与同震滑坡之间的复杂关系，地震滑坡的预测和防治是非常困难的。目前，从地震动力学机制的角度对地震滑坡的认识还不够全面。本文采用弹塑性谱元并行计算方法，通过半结构化六面体网格建立了一个真实的三维边坡模型，研究了地震诱发滑坡的动力破坏特征。边坡的动力特性采用基于连续介质的方法和Mohr-Coulomb屈服准则进行模拟。位移场的计算使用剪切强度折减技术。采用拟静力地震加载方法定量评价边坡稳定性，并考虑复杂地形条件。北川县新中滑坡是汶川大地震引发的破坏性崩塌滑坡之一，因此被选作研究案例。计算结果的三维可视化定量表明，三维数值模型较好地再现了地震同震滑坡响应及其基本的动力破坏模式，而单纯的二维数值模型无法通过地理信息系统（GIS）和遥感（RS）技术捕捉到这些特征。数值结果还表明，拉伸和剪切断裂的破坏面的发展的性质有显着的影响。此外，地震荷载的存在会对边坡的稳定性产生明显的扰动。对比分析表明，与正常重力条件下的边坡相比，地震作用下的边坡剪切面较短，拉裂面较深。滑坡主要发生在坡体上部向下部的过渡段，表明边坡地形是导致边坡失稳的重要因素之一。虽然该模型是在不存在预先存在的破坏面的情况下构建的，但比较分析表明，通过数值模拟获得的破坏面与破坏后调查的破坏面非常一致。研究结果有助于更好地理解滑坡与地震动力机制的关系。该研究对有效预防和减轻地震诱发滑坡灾害具有现实意义。
Earthquake-induced landslides are serious natural hazards that shocked us with tremendous casualties and great economic losses in many mountainous areas around the world. However, predicting and preventing the earthquake-induced landslides is very difficult due to the complicated relationship between seismic dynamics and coseismic landsliding. Comprehensive understanding of earthquake-induced landslides from the perspective of seismic dynamic mechanism remains inadequate at present. This study employs an elastoplastic spectral element method incorporating parallel computing and represents a realistic three-dimensional slope model via a semi-structured hexahedral mesh to investigate the dynamic failure characteristics of earthquake-induced landslides. Dynamic behaviours of slopes are simulated using a continuumbased approach with a Mohr-Coulomb yield criterion. Displacement fields are calculated using the shear strength reduction technique. Pseudo-static seismic loading is performed to assess the slope stability quantitatively and complex topography is taken into consideration. The Xinzhong landslide that occurred in Beichuan Country is one of destructively collapsing landslides triggered by the Wenchuan earthquake and is therefore selected as a case study for discussion. Three-dimensional visualization of the calculated results quantitatively demonstrated that the three-dimensional numerical model well reproduced the coseismic landsliding response and its essential dynamic failure pattern, which could not be purely captured by Geographic Information Systems (GIS) and Remote Sensing (RS) technologies and calculated using simply two-dimensional numerical model. The numerical results also showed that tensile and shear fractures had significant influences on the nature of the failed surface development. In addition, the presence of seismic loading in the slope could cause obvious disturbances for the slope stability. Comparative analysis indicated that the shear surface of the earthquake-induced slope was shorter and the tension crack surface was deeper than that of the normal gravity condition. Moreover, the landslide mainly occurred in the transition from the upper to lower part of the slope, indicating that the slope topography was one of the crucial factors resulting in slope failure. Although the model was constructed without the presence of a pre-existing failure surface, comparative analysis addressed that the failure surface obtained by the numerical simulation was in close agreement with that by the post-failure investigations. The results could provide insight into better understanding of the relationship between landslide and seismic dynamic mechanism. The study has practical significance for the effective prevention and mitigation of earthquake-induced landslide hazards.