含大石块泥石流冲击作用下框架结构房屋动力响应研究

Dynamic response of frame structure building under impact of debris flow with large stones

基于光滑粒子流体动力学-有限元法(smoothed particle hydrodynamics-finite element method,SPH-FEM)耦合的数值方法,分别从结构破坏形态、冲击力时程、关键点位移和速度、系统能量等方面,研究含大石块泥石流冲击作用下框架结构房屋的动力响应和破坏机理。计算结果表明:SPH-FEM耦合方法能够较好地模拟泥石流冲击爬高、绕流扩散、淤积稳定过程。考虑了三种泥石流强度等级,在低、中强度冲击情况下,框架房屋填充墙受到破坏,房屋结构整体保持稳定;在高强度冲击情况下,可以观察到框架房屋的逐步倒塌过程,框架柱损坏模式体现了剪切破坏或塑性铰链失效机制。对于房屋结构而言,泥石流的冲击破坏能力主要来自龙头的冲击力,龙身冲击力相对于龙头降幅约34.2%,大石块的集中作用是结构柱体局部破坏的主要原因。系统能量主要通过泥石流动能转化为结构内能(17.8%)和摩擦耗能(82.8%)。

Here,based on SPH-FEM(smoothed particle hydrodynamics-finite element method)coupled numerical method,dynamic response and failure mechanism of frame structure building under impact of debris flow with large stones were studied from aspects of structural failure morphology,impact force time history,key point displacement and velocity and system energy.The calculation results showed that SPH-FEM coupled method can better simulate processes of debris flow impact climb,flow diffusion and sedimentation stability;3 levels of debris flow intensity are considered,under low and medium intensity impact conditions,infill walls of frame houses are damaged,and the overall structure of house keeps stable;under high-strength impact conditions,gradual collapse process of frame houses can be observed,and failure modes of frame columns reflect shear failure or plastic hinge failure mechanism;for building structure,impact failure ability of debris flow mainly comes from impact force of dragon head;impact force of dragon body decreases by about 34.2% compared to that of dragon head,and the concentrated effect of large stones is the main reason for local failure of structural columns;system energy change exhibits kinetic energy of debris flow being converted into structural internal energy about 17.8% and frictional energy about 82.8%.