A Spatial Numerical Approach for Heterogeneous Slope Stability Analysis in Open Pit Mines

露天矿非均质边坡稳定性分析的空间数值方法

• 批准号: RGPIN-2014-03992
• 负责人: Esmaeili, Kamran
• 金额: $ 1.75万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=679515
• 关键词: Spatial; Numerical; Approach; Heterogeneous; Slope

It is common practice in the preliminary stages of pit slope design to consider the engineering mechanical properties of rock masses, encountered at the mine site, as constant. The average parameter values obtained from sampling of each rock mass are considered to be characteristic of the mechanical properties of that rock unit. Deterministic conventional techniques used to characterize the engineering mechanical properties of rock masses take into account neither the spatial fluctuations of rock mass properties nor the uncertainty in the properties. This can result in over- or under-estimation of engineering rock mass properties and can have a significant impact on the results of any slope stability analysis. Under-estimation of engineering rock mass properties can result in the under-estimation of safety factors in pit slope design, entailing unnecessary stripping costs and imposing extra time and operational constraints. On the other hand, over-estimation of engineering rock mass properties can lead to the design of pit slopes with a higher risk of instability. **This research project aims to develop new advanced modeling approaches that will allow incorporation of the spatial variability of rock mass properties into the pit slope design process. The main objective of this work is to advance the understanding of the influence of spatial variability and anisotropy of rock masses on the mechanics of rock slope failure. This methodology would allow the inherent heterogeneity of rock masses to be taken into account in open pit mine planning and design, on the understanding that more accurate knowledge of the spatial distribution of rock mass mechanical properties promotes safe and economic pit design.**In the course of this research project, the geotechnical information (borehole database, ground mapping and core testing information) from two open pit mine sites will be used as known values of rock mass mechanical properties. The geological and geotechnical field information allows the boundaries and contacts of different geotechnical zones in the study area to be identified. In practice, each domain takes the form of a 3D solid model or envelope. This will be followed by division of the geotechnical domains into 3D blocks. A geostatistical simulation approach will be used to generate spatially variable properties of rock mass, based on the available sampling data. Several realizations of the spatial variability of the geomechanical properties will be created in the form of 3D block models. These block models together with discrete fracture network models will be used as inputs for generation of 3D continuum and brittle fracture numerical models for rock slope stability analysis. A Monte-Carlo simulation approach will be used for slope stability analyses of the stochastic numerical models. This allows to relate probability of slope failure to spatial variability of geomechanical properties and consequently better quantification of uncertainty and risk. These innovative spatial numerical models enable more effective assessment of pit slope design. Consequently, this will have a very positive impact on the economic and technical aspect of open pit mine planning and design.

在矿坑边坡设计的初始阶段，通常的做法是将矿场遇到的岩体的工程力学特性视为恒定。从每个岩体采样获得的平均参数值被认为是该岩石单元的力学特性的特征。用于表征岩体工程力学性质的确定性常规技术既没有考虑岩体性质的空间波动，也没有考虑性质的不确定性。这可能导致工程岩体特性的高估或低估，并对任何边坡稳定性分析的结果产生重大影响。低估工程岩体特性可能导致低估坑边坡设计中的安全系数，从而带来不必要的剥离成本并施加额外的时间和操作限制。另一方面，对工程岩体特性的高估会导致坑边坡设计具有较高的失稳风险。 **该研究项目旨在开发新的先进建模方法，将岩体特性的空间变化纳入矿坑边坡设计过程中。这项工作的主要目的是加深对岩体空间变异性和各向异性对岩质边坡破坏力学影响的理解。这种方法将允许在露天矿规划和设计中考虑岩体固有的非均质性，因为更准确地了解岩体力学特性的空间分布可以促进安全和经济的矿坑设计。**在在本研究项目过程中，来自两个露天矿场的岩土信息（钻孔数据库、地面测绘和岩心测试信息）将被用作岩体力学特性的已知值。地质和岩土领域信息可以识别研究区域中不同岩土区域的边界和接触。实际上，每个域都采用 3D 实体模型或封套的形式。随后将岩土领域划分为 3D 块。根据可用的采样数据，将使用地质统计模拟方法来生成岩体的空间可变特性。地质力学特性的空间变异性的几种实现将以 3D 块模型的形式创建。这些块模型与离散断裂网络模型一起将用作生成用于岩坡稳定性分析的 3D 连续体和脆性断裂数值模型的输入。蒙特卡罗模拟方法将用于随机数值模型的边坡稳定性分析。这样可以将边坡破坏的概率与地质力学特性的空间变化联系起来，从而更好地量化不确定性和风险。这些创新的空间数值模型可以更有效地评估矿坑边坡设计。因此，这将对露天矿规划和设计的经济和技术方面产生非常积极的影响。