【摘要】 分层岩土介质的爆炸效应是一个复杂的动力学问题,运用离散元框架内的三维梁–颗粒模型模拟分层岩土介质的爆炸效应。把介质用颗粒单元离散化,在相邻颗粒间添加梁,这样研究对象就成为一个由颗粒单元与梁网络形成的复合结构。梁的作用是使颗粒的集合体具有与初始对象近似的强度性质。用离散元法描述颗粒单元的运动,并通过相邻颗粒间的相对位移计算梁的变形,根据梁的强度准则判别梁是否存在;裂纹的产生及碎块的形成通过梁的消失来体现。然后采用矩阵位移法计算梁的受力,并反作用于对应的颗粒单元上。模拟结果表明,梁–颗粒模型可以克服以连续介质力学为基础的有限元等数值方法对于模拟大变形时的局限性,可以逼真地体现爆炸载荷下裂纹的生成、扩展以及碎块的形成及飞离母体等大运动特征,且模拟结果与试验结果基本一致,该方法可用于爆炸效应数值模拟,是一种有效的手段。更多还原

【Abstract】 It is a very complicated problem to simulate the blasting effects of multi-layer geomaterials.Three-dimensional beam-particle model in the frame of DEM(discrete element method) is used to simulate the blasting effects of multi-layer geomaterials.The media have been discretized by spherical elements;and the elements in contacts are connected by beams.So the media are simplified into compound structure,which is composed of particles and beams.The aggregate of particles had the similar strength to the initial media because of the action of beams.The DEM is employed to simulated movements of particle,and the deformations of beams are calculated by the relative displacements between particles in contact.A strength law of beams is used to verify whether a deformed beam exists or not.The emergence of cracks and formation of fragments can be simulated by removed beams whose deformations meet the strength rule.The matrix-displacement method is used to calculate forces of beams,and the forces of beams are exerted on particles as opposite forces.The results show that the large deformations of geomaterials induced by blast can be simulated well by the particle-beam model than those of finite element method based on the continuous mechanics.The model can realistically reflect the crack generation and extension,and the shivers formation and materials shifting away from matrix.The simulation results are approximately coincident with test results.So,the beam-particle model is a valid method to simulate mechanical behaviors with high loading rate.更多还原