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为有效描述动力灾变过程中挡土墙附近土体的细观特性,并大量减小离散元模拟的颗粒数目,节省计算时间,利用离散-连续耦合动力数值模型,模拟了已有离心机试验中重力式挡土墙的地震响应。靠近挡土墙的土体区域用相互作用的离散颗粒模拟,远离挡土墙的土体采用连续模型模拟,编写结构的动力有限元程序并嵌入离散元软件中来模拟挡土墙。通过离散元软件PFC2D和有限差分软件FLAC2D的交互运算实现耦合过程。耦合方法的核心在于:①在离散-连续土体的交界面保证连续性;②模拟中离散区域土体的宏观性质与连续土体模型一致。为进一步满足以上两点,分别提出了新的边界耦合力提取方法和自振柱模拟方法。研究表明耦合方法可以从细观尺度上有效描述土体与结构的相互作用和关心区域的土体特性。
In order to effectively describe the mesoscopic characteristics of soil around the retaining wall during dynamic catastrophic process and to reduce the number of particles in the discrete element simulation greatly and save the calculation time, the discrete-continuous coupled dynamic numerical model is used to simulate the existing centrifuge test Seismic response of gravity retaining wall. The soil near the retaining wall is modeled by interacting discrete particles. The soil away from the retaining wall is modeled continuously. The structural dynamic finite element program is programmed and embedded in the discrete element software to simulate the retaining wall. Through the discrete element software PFC2D and finite difference software FLAC2D interactive computing coupling process. The core of the coupling method is as follows: (1) continuity is ensured at the interface between discrete and continuous soils; (2) the macroscopic properties of soils in the discrete area are consistent with the continuous soil model. In order to further satisfy the above two points, a new method of boundary coupled force extraction and self-oscillating column simulation are proposed. The research shows that the coupling method can effectively describe the interaction between soil and structure and the soil characteristics of the concerned region from the mesoscopic scale.