矿山尾砂胶结充填体抗拉强度测试方法研究进展

Research progress on test methods for measuring tensile strength of cemented tailings backfill

矿山尾砂胶结充填是实现金属矿绿色开采的重要技术载体,尾砂胶结充填体抗拉力学性能是影响矿山采场充填体整体稳定性以及确保相邻采场安全高效充填采矿的关键要素。科学、准确测量尾砂胶结充填体抗拉强度是确保矿山充填材料强度合理设计的重要环节。尾砂胶结充填材料属于低强度材料,我国尚无针对尾砂胶结充填材料抗拉性能的统一试验方法或测试标准。系统回顾了矿山充填材料抗拉强度测试方法的应用情况,并指出了当前借鉴混凝土、岩土工程等领域抗拉强度测试方法存在的问题。从抗拉强度直接拉伸测试方法、抗拉强度间接拉伸测试方法和适用于尾砂胶结充填材料的抗拉强度测试方法创新3个方面介绍了最新的测试方法研究应用进展。首先系统梳理总结了4种直接拉伸测试方法及其应用场景,然后研究分析了3种间接拉伸测试方法及其应用条件,并对比分析了两大类不同测试方法的优缺点。在研究分析上述测试方法的基础上,并考虑尾砂胶结充填材料的力学特性,创新发明了一种“工字型”尾砂胶结充填体抗拉强度测试法,研发了相应的压-拉转换装置,实现了用单轴压缩的方式开展胶结充填体试样直接拉伸测试。经中国和加拿大相关矿山和研究机构验证,该方法是适用于矿山尾砂胶结充填材料抗拉性能测试的科学方法,目前已被国际矿业咨询机构—Paterson&Cooke公司、加拿大2家矿业公司、中国3家矿业公司采用,可为国内外金属矿山充填采矿研究与设计提供参考与技术支撑。

The utilization of cemented tailings backfill technology plays a pivotal role in achieving eco-friendly mining of metal ores.The tensile strength of the cemented tailings backfill is a crucial factor that influences its stability and guarantees safe and effective mining with backfill in adjacent stopes.Ensuring rational mine backfill design requires accurate measurement of cemented tailings backfill tensile strength.Cemented tailings backfill,due to its low-strength characteristics,lacks a unified test method or standard for its tensile properties in China.This article presents a systematic review of the application of tensile strength test methods for cemented tailings backfill.It also identifies the current issues with the existing testing methods referenced from concrete,geotechnical engineering,and other fields.The recent developments in the field of tensile testing methods were discussed in this article,focusing on three aspects:direct and indirect test methods,as well as innovations in test methods for measuring the tensile strength of cemented tailings backfill.Firstly,four direct tensile test methods and their application scenarios are systematically sorted out and summarized,and then three indirect tensile test methods and their application conditions are studied and analyzed,and the advantages and disadvantages of the two different types of test methods are compared and analyzed.Based on research and analysis of the above test methods,Prof.Guo of BGRIMM developed a new method of testing the tensile strength of cemented tailings backfill.This method involves using a compression to tensile load converter on dog-bone-shaped specimens,which enables direct tensile strength testing through uniaxial compression.The innovation takes into account the mechanical characteristics of the cemented tailings backfill and provides more accurate results.The method has been scientifically verified by relevant mines and research institutes in China and Canada for evaluating the tensile properties of cemented tailings backfill.It has been adopted by Paterson and Cooke,an international mine backfill consultancy firm,as well as two Canadian mining companies and three mining companies in China.The method can provide references and technical support for the research and design of metal mine backfill both domestically and internationally.