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

矿山回填体是为了经济地建立和保持安全的工作条件，用于充填采矿所形成的地下坑道的一种或多种材料。如今，高质量的回填混合物可以减少水泥含量，能够满足更严格的生产和环境要求，同时对作业的风险最小。精心设计的回填设计、工艺或实践必须是安全的，特别是对于采用侧切采矿方法的作业。尽管回填体的工程设计已经很发达，但在充填体质量与开挖边界之间的相互作用方面，特别是在处理充填体下开采（侧切开采）的情况下，还存在许多未知、不理解或不应用的问题。在充填体下开采时，充填柱底部完全暴露，由于支撑最小，充填体可能会破坏，造成严重后果。为了建立更安全、更高效、成本更低的挖矿方法，目前的回填设计和布置仍然需要进行一些改进。本研究的目的是建立关键的开挖边界参数，如墙壁粗糙度和墙壁闭合对不同尺寸的基坑中不同填土混合料用于基础垫层施工的性能的影响。一个30克吨的离心机构成了主要的建模工具，辅以分析和数值模拟方法。这项研究的预期意义在于开发一种改进的、准确的silmat设计程序，并将改进目前基于经验和试错方法的技术。将制定工业设计的详细方法、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.