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多次典型地震的灾后实地调查都表明震中附近的竖向地震力作用十分明显,而传统的斜坡动力响应分析仅考虑了水平地震力的作用。文中运用离散元数值模拟技术,对震中附近的斜坡体在具地域性和空间非均质性的地震纵横波时差耦合作用下产生崩滑破坏的动力全过程进行了研究,确定了地震动力作用触发的震中附近斜坡体崩滑破坏的形成机制及主控因素。研究表明:对于地震作用下震中附近的斜坡体崩滑破坏,由于纵横波作用的时间差较短,其崩滑形成机制多为受地震纵横波的耦合作用,即竖向周期拉压与水平周期剪切的耦合作用,在此基础上又以纵波的竖向拉伸作用占优,即表现为拉剪破坏形式;此外,在地震构造组合机制、岩体结构与构造、斜坡岩体风化程度及物理力学参数等因素既定的情况下,地震力作用(即地震纵波的周期拉压和地震横波的周期剪切耦合作用)是诱发斜坡体产生初期崩滑破坏的主控因素,而斜坡所处地形(如高程差、沟谷延伸方向)则是促使破坏后的斜坡体形成后续碰撞解体及碎屑流等运动过程的控制诱发因素。
The post-disaster field surveys of many typical earthquakes all showed that the vertical seismic force near the epicenter was very obvious, while the traditional slope dynamic response analysis only considered the horizontal seismic force. In this paper, the discrete element numerical simulation technique is used to study the whole process of the landslide near the epicenter under the coupling of seismic wave and shear wave with regional and spatial heterogeneity, and the dynamic process of the earthquake is triggered The formation mechanism and main controlling factors of landslide damage near the epicenter of the epicenter were analyzed. The results show that the slip-slip mechanism of the sloshing near the epicenter under seismicity is short due to the short time difference between the S-wave and the S-wave, On the basis of this, the vertical tensile action of longitudinal wave is dominant, which is the form of tensile shear failure. In addition, the mechanism of seismic tectonics, the structure and structure of rock mass, the weathering degree and physical Mechanical parameters and other factors given the circumstances, the role of seismic forces (that is, the seismic longitudinal wave compression and seismic shear wave shear coupling) is the main factor inducing slope collapse and collapse of the primary control factor, while the slope where the topography ( Such as elevation difference, extending direction of the valleys) is the predisposing factor that causes the destructive slope body to form the subsequent collision disintegration and debris flow.