散粒体中锚杆间距的锚固效应研究

采用细观数值模拟方法研究散粒体的锚固效应,基于随机模拟技术生成三维多面体颗粒及其在空间中的分布,在随机散粒体不连续变形模型的基础上将砾石锚固试验进行数值实现,分析加锚散粒体材料的宏观与细观力学性能,研究加锚密度及其与颗粒粒径的关系对散粒体力学性质的影响,并探讨锚杆在散粒体材料中的作用机制。分别建立不同锚杆间距和不同颗粒粒径的数值试样,数值模拟结果表明:散粒体锚固数值试验能够较好地反映不同加锚散粒体结构的变形规律与锚固效应;散粒体材料的宏观特性与其细观组构的演化密切相关;锚杆加固散粒体的作用机制为加锚散粒体内形成压缩区,挤压加固作用提高了散粒体间的接触作用力,散粒体结构的整体性得到加强并能承受一定荷载;不考虑锚杆长度的情况下,当锚杆间距小于3倍的散粒体平均粒径时,锚杆能够有效地加固散粒体形成稳定结构。

Study of anchoring effect of anchor spacing in granular mixture

The anchoring effect of granular mixture is studied using the mesoscopic numerical simulation method. Three-dimensional polyhedral particles and their distributions are built based on stochastic simulation technology. With the stochastic granule discontinuous deformation model and the simulation of anchors, the numerical implementation of the bolted gravel experiment is realized. The macroscopic and mesoscopic mechanical performances of anchored granular material are analyzed. The impact of the anchor density and its relationship with the particle size on the mechanical properties of granular mixture is studied; and the anchorage mechanism of granular mixture is discussed. Samples with different anchor spacings and different particle sizes are generated. The simulated results show that the numerical anchored granular mixture experiment can well reflect the deformation and anchoring effect of the different anchored granular structures; and their macroscopic properties have some relationship with the evolution of mesoscopic fabric. The anchorage mechanism is that the compression zone is formed in granular mixture, and the contact forces between granular materials are reinforced by the squeeze effect. Granular structural integrity has been strengthened and the structure is able to withstand a certain load. Without considering the anchor length, when the anchor spacing is less than three times the average particle size of granular mixture, the anchors can effectively reinforce granular mixture and a stable structure can be formed.