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: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=610768
• 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.

在坑坡设计的初步阶段，这是常见的实践，它考虑了在矿场遇到的岩石块的工程机械性能，这是恒定的。从每个岩体的采样获得的平均参数值被认为是该岩石单元的机械性能的特征。用于表征岩体工程机械性能的确定性常规技术既不考虑岩体质量特性的空间波动，也不考虑到特性的不确定性。这可能会导致工程质量质量特性过高或低估，并可能对任何坡度稳定性分析的结果产生重大影响。估计工程岩石质量的估计可能导致坑坡设计中的安全因子低估，需要不必要的剥离成本，并施加额外的时间和操作限制。另一方面，工程质量质量特性的过度估计会导致设计山坡的设计，并具有较高的不稳定性风险。 该研究项目旨在开发新的高级建模方法，以允许将岩体质量特性的空间变异性纳入坑坡设计过程。这项工作的主要目的是促进对岩石质量空间变异性和各向异性对岩石斜率故障力学的影响的理解。这种方法将使岩石块的固有异质性在露天矿山计划和设计中考虑到以下理解，即更准确地了解岩体机械性能的空间分布会促进安全和经济的坑设计。 在该研究项目的过程中，来自两个开放坑矿场的岩土技术信息（钻孔数据库，地面映射和核心测试信息）将用作岩体机械性能的已知值。地质和岩土田地信息允许确定研究区域不同岩土区域的边界和接触。实际上，每个域采用3D实体模型或信封的形式。然后将岩土域分为3D块。基于可用的采样数据，将使用一种地理模拟方法来生成岩体质量的空间可变特性。将以3D块模型的形式创建地质力学特性的空间变异性的几个实现。这些块模型以及离散断裂网络模型将用作生成3D连续体和脆性断裂数值模型的输入，用于岩石斜率稳定性分析。蒙特 - 卡洛模拟方法将用于随机数值模型的斜率稳定性分析。这允许将斜率失效的概率与地质力学特性的空间变异性联系起来，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对坑斜率设计进行更有效的评估。因此，这将对开放坑矿山计划和设计的经济和技术方面产生非常积极的影响。