基于闵科夫斯基差和优化波前法的二维天然堆石料生成方法及应用

Generation and application of rockfill based on the Minkowski difference and the optimized advance front method

提出一种新的二维天然堆石料生成方法,该方法生成的二维堆石料模型含有与天然块石形态一致的复杂块石,且同时满足任意块石粒径、倾角、长短轴比分布。首先采用数字图像处理技术,获取大量天然块石的形态信息,建立天然块石的形态库;然后基于碰撞判定中的闵科夫斯基差,实现块石的快速重叠判定和新块石的快速堆叠计算;最后结合高体积率的颗粒优化波前堆叠法,生成最终二维天然堆石料模型。与现有方法相比,新方法生成的块石形态与天然块石形态一致,可以同时考虑任意块石粒径、倾角、长短轴比分布,且生成的堆石料模型具有较高的生成效率和块石堆叠体积率,Matlab环境下常规矩形堆石料堆叠速度>800个/s,堆叠体积率>75%。通过天然堆石料生成案例和3个不同粒径堆石料的UDEC直剪试验模拟,表明提出的新方法可以准确描述二维天然堆石料的块石形态和细观结构特征,从而可以广泛用于二维天然堆石料的力学性能分析。

A new conditional algorithm for generating granular packing is proposed,by which the granular has the same complex geometries with the realistic granular and follows the target particle size,orientation angle and aspect ratio distributions. Firstly,amounts of morphology information of realistic granular is obtained through original particle image and a database is established. Secondly,by using the Minkowski difference for collision detection,the particle overlap check and the new particle packing could be carried out efficiently. Finally,in combination with the optimized advance front method,a particle packing model is generated,particle-by-particle. Compared with the existing methods,the granular generated by the developed method has the same complex geometries as the realistic particles and can consider arbitrary particle size,orientation angle and aspect ratio distributions. In addition,the granular packing model generated has a higher packing rate and packing volume ratio,for instance,respectively more than 800/s and 75% for rectangle particles in the MATLAB environment. A generation of complex granular material demonstrates the particle packing generated by the method can represent the same geometries and microstructure of realistic granular. Three direct shear test simulations carried out by the discrete element software of UDEC reveal that the developed method can be widely used in the analysis of mechanical properties of granular materials.