In practical rock engineering, Universal Distinct Element Code (UDEC) is one of the most widely used two-dimensional software packages for simulating discontinuum behaviors of rocks and rockmasses. Over the years, this software has been used to study phenomena, such as grain-scale fracturing in laboratory specimens, spalling around tunnels and roadways, shearing and separation along discontinuities in jointed rockmasses, etc. One of the lesser discussed topics in context of explicit time-stepping discontinuum modeling in UDEC is the damping mode employed for such simulations. For static analysis, the ‘local’ (default) and ‘combined’ damping modes are generally used, but their effects on the emergent model response as well as their suitability to a particular problem are not well documented in the literature. To help bridge this gap, this study contrasts the responses of a laboratory-scale model, a hypothetical granite pillar model and a hypothetical coal mine entry model with ‘Local’ and ‘Combined’ damping modes. It was found that in small-scale simulations, the results using ‘Local’ and ‘Combined’ damping modes were similar, but the differences were significant in the field-scale models. In particular, ‘Local’ damping mode tended to suppress large deformations, predicted high pillar strengths and increased model run-time significantly. Although it is difficult to definitively establish which of the two damping mode leads to more realistic excavation-scale behavior in a given scenario, the authors suggest the use of ‘Combined’ damping for models of individual excavations where large deformations and block separations are expected.

在实际的岩石工程中，Universal Distinct Element Code (UDEC) 是应用最广泛的用于模拟岩石和岩体不连续体行为的二维软件包之一。多年来，该软件已被用于研究各种现象，例如实验室标本中的颗粒尺度破裂、隧道和巷道周围的剥落、节理岩体中沿不连续面的剪切和分离等。 显式上下文中讨论较少的主题之一UDEC 中的时间步进不连续建模是用于此类模拟的阻尼模式。对于静态分析，通常使用“局部”（默认）和“组合”阻尼模式，但它们对紧急模型响应的影响以及它们对特定问题的适用性在文献中没有很好的记录。为了帮助弥合这一差距，本研究将实验室规模模型、假设的花岗岩柱模型和假设的煤矿入口模型的响应与“本地”和“组合”阻尼模式进行了对比。发现在小规模模拟中，使用“局部”和“组合”阻尼模式的结果相似，但在现场规模模型中差异显着。特别是，“局部”阻尼模式倾向于抑制大变形，预测高支柱强度并显着增加模型运行时间。尽管很难确定在给定情况下两种阻尼模式中的哪一种会导致更真实的开挖规模行为，但作者建议将“组合”阻尼用于预计会出现大变形和块体分离的单个开挖模型。