Strainburst potential identification and support of stress-fractured ground

尽管目前财政拮据，但采矿业仍在增长，周期可能很长，这为加拿大扩大矿产生产创造了独特的经济机会。然而，找到一个新的矿体需要数年时间，获得一个新矿的许可和运营通常需要8到15年。因此，向深部扩展矿山寿命是最具吸引力的。不幸的是，深层开采成本更高，投资者只有在项目对工人、投资者、社会和环境的风险较低的情况下才愿意投入资金。本研究主要集中在前两个方面。*作为研究接受者的利益相关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)对高应力（裂隙）地基进行支护设计，优化施工可施工性，实现高进度。两者都是确保深度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。根据现场观测，指出了当前岩石工程的两个主要缺陷：*(1)应变冲击潜力识别-岩爆评估和支护设计的标准方法是基于造成破坏的能量来自地震事件（断层滑动）的前提。这种方法忽略了基坑附近储存的能量，因此存在很大的不足。此外，假设应变破裂的潜在位置与局部变形的潜力有关。如果得到验证，将通过菌株爆发潜在识别方法在创建更安全的工作场所方面取得进展。*(2)应力断裂地面的支撑-在深度上，如果不在开挖周围形成应力断裂地面，就不可能进行采矿。由于深层岩石的硬岩性质，这种压裂过程与几何体积增加有关，称为膨胀，这对支撑系统施加了严重的压力。目前基于力平衡或能量耗散平衡的设计方法是不充分的，拟议的研究将发展基于变形的支撑设计程序。*将对岩石压裂过程进行评估，以更好地识别应变冲击潜力和膨胀特性，并改进相应的地面表征技术。*这项研究包括基础研究、实地监测/观察和反向分析，将发展适当的方法来描述岩石的深度特征，以便识别应变冲击潜力和设计支护。*拟议的研究是独特的，因为基本假设已被确定和定性验证，因此工业界愿意资助安装监测设备，为这项研究提供数据。*研究结果在执行到采矿作业时，其潜在价值是巨大的。虽然难以量化，但据估计，单次运营就能带来数亿美元的利润。它将有助于创造更安全的工作场所，减少投资者的风险，减少恢复成本，减少生产延误，并可能减少矿石损失。一位行业代表表示，拟议研究项目的潜在价值可能在10亿美元左右。

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.