The effect of excavation boundary conditions on the design of mine backfills

矿山充填是一种或多种材料，用于填充采矿产生的地下采掘，以经济地建立和保持安全的工作条件。如今，高质量的回填混合料可以在减少水泥含量的情况下设计，能够满足更严格的生产和环境要求，并将对运营的风险降至最低。设计良好的充填设计、工艺或实践必须是安全的，特别是对于采用底切采矿方法的作业。尽管充填混合料的工程设计已经得到了很好的发展，但充填体与开挖边界之间的相互作用仍有许多未知、理解或应用的地方，特别是在处理充填(底切开采)情况下的采矿时。当在充填下开采时，充填柱的底部完全暴露，由于托换最少，充填体可能会失效，造成严重后果。目前的充填设计和布置仍需进行一些改进，以建立更安全、更有效和成本更低的底切采矿做法。本研究旨在探讨开挖边界参数，如壁面粗糙度及封闭度等，对不同尺寸开挖之不同垫层回填混合料性能之影响。一台30克吨的离心机构成了主要的建模工具，并辅之以分析和数值建模方法。这项研究的预期意义是开发一种改进的和准确的地垫设计程序，并将改进现有的基于经验和试错法的技术。将为硅胶垫的工业设计制定详细的方法、测试协议和基准程序。

Mine backfill is the material, or materials, used to fill underground excavations created by mining so as to establish and retain safe working conditions economically. Today, high quality backfill mixes can be engineered at reduced cement content and are able to meet stricter production and environmental requirements with minimal risk to the operations. A well-engineered backfill design, process or practice must be safe, in particular for operations employing undercut mining methods. Even though the engineering design of backfill mixes has been well developed, there is much in the interaction between the backfill mass and the excavation boundaries that is not known, understood or applied, particularly when dealing with mining under fill (undercut mining) situations. When mining under fill, the bottom of the fill column is fully exposed and, because of minimum underpinning, the fill mass could fail with dramatic consequences. A number of improvements in current backfill design and placement are still required to establish safer, more efficient and less costly undercut mining practices. This research aims at establishing the effect of critical excavation boundary parameters, such as wall roughness and wall closure on the performance of different backfill mixes used for sillmat construction placed in excavations of differing dimensions. A 30 g-ton centrifuge constitutes the primary modeling tool, supported by analytical and numerical modeling methods. The expected significance of this research is the development of an improved and accurate procedure for sillmat design and will improve present techniques that are based on experience and trial and error methods. Detailed methodologies, test protocols and benchmark procedures for industrial designs of sillmats will be developed.