ABSTRACT

Most pit boundaries at Sishen Mine in South Africa consist of Banded Iron Formation (BIF), which exhibits anisotropic behaviour on a rock mass scale. A generally applicable approach is to apply Synthetic Rock Mass (SRM) modelling to characterise rock mass anisotropy. To characterise the rock mass for slope stability analysis, the persistence of bedding planes is very important. Subsequently, a sensitivity analysis on the effect that bedding persistence has on rock mass strength, was performed. Results indicate that bedding plane sizes less than the sample dimensions, produce higher strengths due to the influence of rock bridges. SRM modelling therefore demonstrates that persistence is a critical factor in rock mass strength analysis and subsequent slope stability analyses. The definition of SRMs is completely reliant on data provided by high quality, bench-scale structural mapping. The importance of geotechnical mapping is discussed, as it is currently the only way to accurately determine persistence. The Sishen study is a case in point that geotechnical mapping remains an essential function to obtain the appropriate rock mass characteristics for slope design. Routine mapping exercises, performed by well-trained geotechnical engineers, will therefore remain critical to acquire the necessary input parameters to advance the cutting edge SRM approach.

摘要

南非Sishen矿的大多数矿井边界由带状铁层（BIF）组成，在岩体规模上表现出各向异性。一种普遍适用的方法是应用合成岩体（SRM）建模来表征岩体各向异性。为了表征岩质以进行边坡稳定性分析，层理面的持久性非常重要。随后，对层理持久性对岩体强度的影响进行了敏感性分析。结果表明，由于岩桥的影响，层理平面尺寸小于样品尺寸会产生更高的强度。因此，SRM建模表明，持久性是岩体强度分析和随后的边坡稳定性分析中的关键因素。SRM的定义完全依赖于高质量的台式规模结构图提供的数据。讨论了岩土制图的重要性，因为它是当前准确确定持久性的唯一方法。Sishen研究就是一个例子，岩土测绘仍然是获得适当的岩质特征以进行边坡设计的一项基本功能。因此，由训练有素的岩土工程师进行的常规测绘练习对于获取必要的输入参数以推进最先进的SRM方法仍然至关重要。Sishen研究就是一个例子，岩土测绘仍然是获得适当的岩质特征以进行边坡设计的一项基本功能。因此，由训练有素的岩土工程师进行的常规测绘练习对于获取必要的输入参数以推进最先进的SRM方法仍然至关重要。Sishen研究就是一个例子，岩土测绘仍然是获得适当的岩质特征以进行边坡设计的一项基本功能。因此，由训练有素的岩土工程师进行的常规测绘练习对于获取必要的输入参数以推进最先进的SRM方法仍然至关重要。