Development of design criteria for working under weak rock masses

这是作者在过去十五（15）年中为运营商开发设计工具的研究的延伸。候选人的小组已开发出经验设计方法，并在世界各地的矿山设计中采用。这些主要是为被归类为良好的岩体开发的。采矿业现在正在开采需要在更困难的条件下开采的矿石，例如在较弱的岩体下。为人工进入方法开发的原始“跨度设计曲线”确定了给定岩体可以打开的临界跨度。它主要基于RMR超过55%或Q大于4.0且基本上无支撑的岩体。该建议着眼于扩展数据库，以纳入软弱岩体沿着，并量化支护对整个设计过程的影响。目标是建立一个安全的工程工作环境，因为采矿就在裸露的背部下方进行，对操作员造成最大的暴露。将编制一个扩大的数据库，特别强调加拿大的条件和做法。将从应力、结构和岩体的角度分析各个矿井开口，以评估背部稳定性，并为工程师制定标准，以确保工作场所的安全。将对破坏机制进行建模，并根据可变岩体的实际矿山观测条件进行校准。这将估计破坏的深度，从而估计可能作用在支架上的潜在载荷。这将产生不同支撑类别的设计曲线。将根据现场观察和测量结果对分析、经验和数值代码等工具进行校准，以得出可行的解决方案，用于给定支护类型的软弱岩体内的支护设计。

This is an extension of research performed by the author over the past fifteen(15) years in developing design tools for the operator. Empirical design approaches have been developed by the candidate's group that are employed in mine designs throughout the world. These have been developed largely for rock masses classified as being fair to good. The mining industry is now extracting ores that require mining under more difficult conditions such as under weaker rock masses. The original "Span Design Curve" as developed for man-entry methods  identifies the critical span that can be open for a given rock mass. It is largely based upon rock masses having an RMR in excess of 55% or Q greater than 4.0 that are largely unsupported. This proposal looks at extending the database to incorporate the weak rock masses along with quantifying the effect of support on the overall design process. The objective is to develop a safe engineered work environment as mining occurs immediately underneath the exposed back and causes the greatest exposure to the operator. An expanded database will be compiled with particular emphasis on Canadian conditions and practices. Individual mine openings will be analysed in terms of stress, structure and the rock mass in order to assess back stability and to develop criteria for the engineer to ensure a safe workplace. The failure mechanism will be modeled and calibrated to actual mine observed conditions for variable rock masses. This will estimate the depth of failure and consequently the potential loading that may act on the support. This will result in design curves for varying support categories. Tools such as analytical, empirical and numerical codes will be calibrated to site observations and measurements to arrive at a workable solution for purposes of design of backs within weak rock masses for a given support type.