动力荷载下散粒体的锚杆加固效应

Anchoring effect of granular mixture under dynamic loads

采用细观数值模拟方法研究动力荷载下散粒体的锚杆加固效应,采用随机散粒体不连续变形方法建立加锚散粒体的三维数值试样,对试样施加水平方向的动力荷载,分析散粒体材料在动力荷载条件下的宏观和细观力学特性.分别建立不同锚杆间距、颗粒粒径以及无锚杆的散粒体试样,研究其对动力荷载条件下的散粒体的力学性质影响.数值模拟结果表明:随机散粒体不连续变形方法可以研究动力荷载下散粒体的变形规律及加固效应;锚杆加固可以有效限制散粒体在动力情况下的变形,显著提高散粒体的整体性;与静力加载相同,由于锚杆的挤压使散粒体产生侧向压力,加强了颗粒间的接触作用力;锚杆长度相同的情况下,加锚密度越大,散粒体试样的抗震稳定性越好;当锚杆间距与散粒体平均粒径的比值小于2.35时,锚杆可以很好地提高散粒体结构的自稳能力而保持整体稳定.

In this paper the anchoring effect of granular mixture under dynamic loads is studied by using mesoscopic numerical simulation method. With the stochastic granular discontinuous deformation method, three-dimensional numerical models of anchored granular mixture are built based on stochastic numerical simulation technology. A horizontal seismic acceleration time-history is input to applying the dynamic load. The macroscopic and mesoscopic mechanical performance of anchored granular material under dynam- ic loads is analyzed. Numerical models with different anchor spacings and different particle sizes are gener- ated respectively; meanwhile, a numerical model without anchor is built for comparison, whose impact is studied on the mechanical properties of granular mixture under dynamic loads. The numerical simulation results show that the stochastic granular discontinuous deformation method can study the deformation and reinforcement effect of granular mixture with different anchor densities; anchor reinforcement can effec- tively constrain the deformation and outstandingly improve the structure integrity of granular mixture. Lateral pressure in granular mixture is produced and the contact forces between granular materials are rein- forced due to the squeeze of anchor. In the condition of the same anchor length, aseismic stability of granu- lar mixture is better with the increasing anchor density. When the ratio of anchor spacing and the average particle size of granular mixture is less than 2.35, the anchors will be able to improve the self-stability and remain the overall stability of granular mixture.