Collapse of granular material is usually accompanied by long run-out granular flows in natural hazards, e.g. rock/debris flow and snow avalanches. This paper presents a novel multi-scale approach for modelling granular column collapse with large deformation. This approach employs the smoothed particle hydrodynamics (SPH) method to solve large deformation boundary value problems, while using a micromechanical model to derive the nonlinear material response required by the SPH method. After examining the effect of initial cell size, the proposed approach is subsequently applied to simulate the flow of granular column in a rectangular channel at a low water content by varying the initial aspect ratio. The numerical results show good agreement with various experimental observations on both collapse process and final deposit morphology. Furthermore, the meso-scale behaviour is also captured owing to the advantages of the micromechanical model. Finally, it was demonstrated that the novel multi-scale approach is helpful in improving the understanding of granular collapse and should be an effective computational tool for the analysis of real-scale granular flow.

颗粒状物质的崩塌通常伴随着自然灾害（例如岩石/泥石流和雪崩）中长期流失的颗粒状流动。本文提出了一种新的多尺度方法，用于建模具有大变形的粒状柱倒塌。该方法采用平滑粒子流体动力学（SPH）方法来解决较大的变形边界值问题，同时使用微力学模型来推导SPH方法所需的非线性材料响应。在检查了初始孔尺寸的影响后，通过改变初始长宽比，随后将所提出的方法应用于模拟低水含量矩形通道中粒状柱的流动。数值结果与崩塌过程和最终沉积形态的各种实验观察结果吻合良好。此外，由于微力学模型的优势，中尺度行为也被捕获。最后，证明了新颖的多尺度方法有助于增进对颗粒塌陷的理解，并且应该是分析真实尺度颗粒流的有效计算工具。