Development of a Rockbolt Support Element for Discontinuous Deformation Analysis

用于不连续变形分析的岩石锚杆支撑元件的开发

• 批准号: 0201577
• 负责人: Mary MacLaughlin
• 金额: $ 6.96万
• 依托单位: Montana Technological University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-01 至 2005-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0201577&HistoricalAwards=false
• 关键词: Development; Rockbolt; Support; Element; Discontinuous; Development; Rockbolt; Support; Element; Discontinuous

CMS-0201577PI: Mary MacLaughlinInstitution: Montana TechTitle: "Development of a Rockbolt Support Element for Discontinuous Deformation Analysis"Astract:The primary objective of this research project is to develop a rockbolt support element that is capable of modeling actual rockbolt behavior, particularly nonlinear movement between the bolt and the rock which is critical for numerical modeling. Discontinuous Deformation Analysis, DDA, has several unique features that make it a perfect candidate for development of a bolt element that has the ability to characterize rockbolt behavior to a much higher degree of realism and accuracy than has previously been possible. DDA is an implicit discrete element method that already has the capacity to model "blocks" of any irregular shape, and the contact routines are specifically designed to efficiently capture contact between blocks with both convex and concave vertex angles. The method accounts for frictional, cohesive, and tensional forces which are present at the contacts, and allows blocks to slide, separate, and impact without penetrating. A rockbolt element will be implemented as a "block" with a particular geometry and special material properties consistent with those of a typical rockbolt. The support-rock interaction mechanics will then be incorporated into the model as manifested by displacement between the bolt element and the surrounding rock blocks. This capability to model bolt behavior, especially pull-out failure, will make the DDA rockbolt element a more accurate modeling tool than other previously developed numerical rockbolt support elements. Mark (2000) states that "the reinforcement mode is actually dictated to the bolts by the ground, rather than the reverse." One of the real strengths of the DDA approach is that this outcome is a natural result of the analysis. The behavior and failure mode do not have to be specified before or during the analysis - they are part of the calculated results.The NIOSH Spokane Research Laboratory, which was a branch of the US Bureau of Mines until 1995 and is now part of the National Institute for Occupational Safety and Health, has invested significant resources into the development, installation and testing of instrumented rockbolts since the mid-1980's. Analysis of the data collected using the instrumented rockbolts has contributed a great deal to the general understanding of the behavior of rockbolt supports, and collaboration with NIOSH personnel is an important component of this project.The development of the bolt element will involve bolt type selection, theoretical development, algorithm development and implementation. The PI and Ms. Kathryn Clapp, the Montana Tech graduate student involved in this project, will jointly work on all of these aspects, with assistance from Mr. Steve Signer of NIOSH. One fairly unique aspect of this project is that once the theoretical development is finished and the rockbolt algorithms have been implemented into the software, validation will be performed using the large archive of NIOSH instrumented rockbolt data which has already been collected. This is a tremendous advantage and will allow the project to be completed in a relatively short period of time, with a modest budget. Ms. Clapp will perform the bulk of the validation activities, which will entail constructing DDA models corresponding to each of the different laboratory test configurations used, and performing analyses with model conditions specified to represent the lab tests as closely as possible. The DDA calculations of the head displacement and load values at points along the bolt will be recorded and compared to actual bolt behavior as observed during the tests.Reference: Mark, C. (2000). "Design of Roof Bolt Systems." In C. Mark, D.R. Dolinar, and R. Tuchman, eds. New Technology for Coal Mine Roof Support, Proceedings of the NIOSH Open Industry Briefing, NIOSH IC 9453, pp. 111-132.

CMS-0201577PI：Mary Maclaughlininstitution：Montana Techtitle：“开发不连续变形分析的岩石支撑元素” ASTRAST：该研究项目的主要目标是开发一个能够建模实际的岩石行为，尤其是螺栓和岩石之间的非线性运动，尤其是对数字模型的非线性运动。 不连续的变形分析DDA具有几个独特的功能，使其成为开发螺栓元件的理想候选者，该元素能够以比以前可能更高的现实主义和准确性来表征摇滚行为。 DDA是一种隐式离散元素方法，它已经具有模拟任何不规则形状的“块”的能力，并且触点例程是专门设计的，可以有效地捕获具有凸面和凹面顶点角度的块之间的接触。 该方法解释了触点处存在的摩擦，凝聚力和紧张力，并允许块在不穿透的情况下滑动，分离和撞击。 摇滚元件将作为“块”实现，具有特定的几何形状和特殊的材料属性，与典型的岩螺栓一致。 然后，支撑摇滚相互作用的力学将被合并到模型中，这是由螺栓元件和周围岩石块之间的位移所表现出来的。 与其他先前开发的数值摇滚支撑元件相比，这种模拟螺栓行为的能力，尤其是拉出故障，将使DDA Rockbolt元件成为更准确的建模工具。 马克（Mark，2000）指出：“加固模式实际上是由地面指向螺栓的，而不是反向。” DDA方法的真正优势之一是该结果是分析的自然结果。 在分析之前或分析期间，不必指定行为和失败模式 - 它们是计算结果的一部分。直到1995年，Niosh Spokane Research Laboratory一直是美国矿业局的一个分支，现在已成为美国国家职业安全与健康研究所的一部分，已将大量资源投资于自1月1980年中期以来的岩石上的开发，安装和测试。 对使用仪表式螺栓收集的数据的分析为对Rockbolt支持的行为的一般理解做出了很大的贡献，与NIOSH人员的合作是该项目的重要组成部分。螺栓元素的开发将涉及螺栓类型选择，理论开发，算法开发和实施。 蒙大拿州科技研究生的PI和Kathryn Clapp女士将在Niosh的Steve Signer先生的协助下共同致力于所有这些方面。 该项目的一个相当独特的方面是，一旦理论开发完成并已将岩石算法实施到软件中，将使用已经收集的大型NIOSH仪器摇滚数据进行验证。 这是一个巨大的优势，将允许该项目在相对较短的时间内完成，预算适中。 Clapp女士将执行大部分验证活动，这将需要构造与所使用的每种不同实验室测试配置相对应的DDA模型，并使用指定的模型条件进行分析，以尽可能地表示实验室测试。 将记录沿螺栓点的头部位移和负载值的DDA计算，并将其与测试过程中观察到的实际螺栓行为进行比较。参考：Mark，C。（2000）。 “屋顶螺栓系统的设计。” 在C. Mark，D.R。 Dolinar和R. Tuchman编辑。煤矿屋顶支持的新技术，NIOSH开放行业简报会议论文集，Niosh IC 9453，第111-132页。