Strainburst potential identification and support of stress-fractured ground

应力断裂地基的应变爆发潜力识别和支护

• 批准号: RGPIN-2014-06251
• 负责人: Kaiser, Peter
• 金额: $ 2.48万
• 依托单位: Laurentian University of Sudbury
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=654992
• 关键词: Strainburst; potential; identification; support; stress

Despite the current financial constraints, the mining sector is growing, likely with a long cycle period, creating a unique economic opportunity for Canada to expand its mineral production. Finding a new ore body, however, takes years and getting a new mine permitted and operational typically takes 8 to 15 yrs. Hence, it is most attractive to expand the mine life by going deeper. Unfortunately, mining at depth is more costly and investors are only willing to commit capital if a project can be executed at low risk to workers, investors, society and the environment. This research focuses on the first two aspects. *The stakeholders, as recipients of research, have identified two geomechanics aspects needing funda-mental and applied research: (1) Assessment and mitigation of risk from strain bursting; and (2) design of support for highly stressed (fractured) ground for optimal constructability to achieve high rates of ad-vance. Both are key elements of ensuring reliability in production at depth.*The proposed research deals with challenges identified through recent experiences from deep under-ground construction and mines. Based on field observations, two key deficiencies in current rock engi-neering are identified: *(1) Strainburst potential identification - standard approaches for rockburst assessment and support design are based on the premise that the damage causing energy comes from a seismic event (fault slip). This approach ignores the energy stored in near the excavation and thus is highly deficient. Furthermore, the potential location for strainbursting is hypothesized to be related to the potential for localized defor-mation. IF validated, progress will be made in creating safer work places through strainburst potential identification methods.* (2) Support of stress fractured ground - at depth it is impossible to mine without creating a skin of stress-fractured ground around an excavation. Because of the hard rock nature of the rock at depth, this fracturing process is associated with geometric volume increase, called bulking, that impose severe strains on support systems. Current design approaches based on force equilibrium or energy dissipation equilib-rium is inadequate and the proposed research will develop deformation-based support design procedures.*The rock fracturing process needed to better identify both strainburst potential and bulking properties will be assessed and respective ground characterizations techniques will be improved.*The research, involving fundamental studies, field monitoring / observations, and back-analyses, will develop means to properly characterize rock at depth for strainburst potential identification and support design.*The proposed research is unique in that underlying hypotheses have been identified and verified qualita-tively such that industry is willing to fund the installation of monitoring equipment to provide the data for this research.*The potential value of the research findings, when implemented into mining operations, is substantial. While hard to quantify, it is estimated to contribute in the hundreds of millions of dollars to the bottom line of a single operation. It will assist in creating safer work places, in reducing investor risks, reducing rehabilitation costs, reducing production delays, and possibly in reducing ore loss. One industry repre-sentative suggested that the potential value of the proposed research program could be in the billion dollar range.

尽管目前存在财政限制，但采矿业正在增长，可能会有一个很长的周期，为加拿大扩大其矿产生产创造了一个独特的经济机会。 然而，寻找一个新的矿体需要数年时间，而获得一个新矿山的许可和运营通常需要8到15年。因此，通过更深的开采来延长矿山寿命是最有吸引力的。 不幸的是，深海采矿成本更高，投资者只愿意在对工人、投资者、社会和环境风险低的情况下实施项目。 本研究主要集中在前两个方面。 * 利益相关者作为研究的接受者，已经确定了需要进行基础和应用研究的两个地质力学方面：（1）评估和减轻应变破裂的风险;（2）设计高应力（断裂）地面的支撑，以实现最佳施工性，从而实现高进步率。两者都是确保深海生产可靠性的关键因素。*拟议的研究涉及通过最近的深地下建筑和矿山经验确定的挑战。 基于现场观测，指出了当前岩石工程中的两个主要缺陷：（1）应变爆可能性识别--岩爆评估和支护设计的标准方法是基于这样一个前提，即引起破坏的能量来自地震事件（断层滑动）。这种方法忽略了在开挖附近储存的能量，因此是非常不足的。 此外，应变破裂的潜在位置被假设为与局部变形的潜力。 如果得到验证，将通过应变爆发潜在识别方法在创造更安全的工作场所方面取得进展。(2)应力破碎地面的支撑-在深部，不可能在开挖周围不产生应力破碎地面的表皮而进行开采。由于深部岩石的坚硬岩石性质，这种压裂过程与几何体积增加（称为膨胀）有关，这对支撑系统施加了严重的应变。 目前基于力平衡或能量耗散平衡的设计方法是不够的，拟议的研究将开发基于变形的支撑设计程序。将对更好地确定应变破裂潜力和膨胀特性所需的岩石破裂过程进行评估，并将改进相应的地面表征技术。这项研究涉及基础研究、现场监测/观察和反分析，将开发适当表征深部岩石的方法，以确定应变破裂的可能性和支护设计。拟议的研究是独一无二的，因为基本假设已经被定性地确定和验证，因此行业愿意资助安装监测设备，为这项研究提供数据。研究结果的潜在价值，当实施到采矿业务，是巨大的。虽然很难量化，但据估计，一次行动的底线就有数亿美元。 它将有助于创造更安全的工作场所，降低投资者风险，减少恢复成本，减少生产延误，并可能减少矿石损失。一位行业代表认为，拟议的研究计划的潜在价值可能在10亿美元的范围内。