Integrated investigations on fracturing processes of highly stressed mine pillars

高应力矿柱破裂过程综合研究

• 批准号: RGPIN-2018-04038
• 负责人: Bahrani, Navid
• 金额: $ 2.26万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=712722
• 关键词: Integrated; investigations; fracturing; processes; highly

Mining contributes significantly to Canadian economy. According to the Mining Association of Canada, mining industry directly employed over 373,000 workers across the country in 2015, and contributed over $56 billion to Canada's Gross Domestic Product (GDP). In recent years, as mines progress to deeper levels (>1.5 km), a more reliable and efficient design of pillars has become increasingly important. A pillar is defined as a column of in-situ rock left between two or more underground openings. Pillars are used in almost all underground mining methods to provide support to mine openings and maintain a safe and stable environment for mine personnel and equipment. A better understanding of pillar mechanics can have a significant impact on the safety of mine personnel as well as the financial benefits of the mines. Pillars can be of different shapes and sizes. The size of pillars, usually expressed as the width-to-height (W/H) ratio, serves as an important design criterion. Typical pillar W/H ratios range between 0.5 and 2.5. Current engineering approaches for pillar design include empirical formulae from data based on in-situ pillar performances as well as numerical modeling, where the rock mass strength is estimated using empirical failure criteria. It is hypothesized that these approaches do not properly estimate the pillar strength at great depths (>1.5 km) due to the following reasons: 1) empirical pillar strength equations came from a database that is not appropriate for pillar design in deep mines; 2) common empirical rock mass strength estimation approaches tend to underestimate the confined strength of massive to moderately jointed rock masses; and 3) common pillar strength assessment approaches based on numerical modeling do not consider mining-induced stress changes, and their influences on progressive rock mass fracturing and strength degradation. The proposed research program aims at developing methods to improve the current understanding of fracturing processes and failure mechanisms of highly stressed pillars in massive to moderately jointed rock masses, subjected to mining-induced stress changes and non-uniform loading conditions. This research program consists of two main components: 1) laboratory-scale physical modeling; and 2) advanced numerical modeling using three-dimensional discontinuum modeling approaches. The outcome of this research program will provide future engineers with tools for a more reliable and economic pillar design in deep mines. This will have a direct impact on the financial and safety performance of Canadian mining companies, and will provide valuable opportunities for the training of Highly Qualified Personnel (HQP).

矿业对加拿大经济的贡献很大。根据加拿大矿业协会的数据，2015年，采矿业在全国直接雇佣了超过373,000名工人，为加拿大的国内生产总值（GDP）贡献了超过560亿美元。近年来，随着矿山向深部发展（约1.5公里），更可靠、更高效的矿柱设计变得越来越重要。矿柱被定义为在两个或多个地下洞口之间留下的原位岩柱。矿柱几乎在所有的地下开采方法中都有使用，为矿井开孔提供支撑，维护矿井人员和设备的安全稳定环境。更好地了解矿柱力学可以对矿山人员的安全以及矿山的经济效益产生重大影响。柱子可以有不同的形状和大小。柱的尺寸通常表示为宽高比（W/H），是重要的设计准则。典型的矿柱W/H比值在0.5 ~ 2.5之间。