Content
内容
2. Theoretical Background 2
2.理论背景2
2.2. Slope Instability 2
2.2.边坡不稳定性2
2.3. TSF Configurations 2
2.3.TSF 配置2
3. Soil Testing and Interpretation 4
3.土壤测试和解释4
3.1. Soil sample data for materials available for dams 4
3.1.大坝可用材料的土壤样本数据4
3.2. Tailings CPT data 5
3.2.尾矿 CPT 数据5
3.3. Seismic data in the region 6
3.3.区域 6 的地震数据
4. Design Basis and Assumption 7
4.设计基础和假设7
4.1. Design Codes and Guidelines 7
4.1.设计规范和指南7
5.1. Basic theory and design methods and digital analysis tools 9
5.1.基本理论和设计方法以及数字分析工具9
5.2. Verification of the instability in seepage and pipe 9
5.2.验证渗流和管道9 中的不稳定性
5.3. Verification of the Slope stability 10
5.3.边坡稳定性验证10
5.4. Validation of resistance to liquefaction 11
5.4.抗液化性验证11
6.1. Draft Sample 12
6.1.草稿样本12
6.2. Verification Results 12
6.2.验证结果12
7.1. Construction techniques and material properties 15
7.1.施工技术和材料特性15
Executive Summary
摘要
The design focuses on the storage of 7,000,000 cubic metres of tailings, and the client required the dam to be constructed in a rectangular area measuring 1,000 metres by 1,000 metres. At the beginning of the project design, three main dam materials were collected and selected. The report found that a single aggregate would result in an excessive amount of earth required for the dam, which would affect the overall efficiency of the project. Therefore, after repeated simulations and adjustments, the design concept of slag-rock layering was established, and the importance of the dam slope to prevent landslide outbursts was clarified, and appropriate drains were designed according to the hydraulic slope drop to cope with the risk of pipe surges.
该设计的重点是储存 7,000,000 立方米的尾矿,客户要求将大坝建在 1,000 米 x 1,000 米的矩形区域内。在项目设计之初,收集并选择了三种主要的大坝材料。该报告发现,单个骨料会导致大坝所需的泥土量过多,这将影响项目的整体效率。因此,经过反复模拟和调整,建立了渣石分层的设计理念,明确了坝体边坡防止滑坡突出的重要性,并根据水力边坡落差设计了合适的排水系统,以应对管道涌动的风险。
In addition, a thorough analysis of the geological data of the mine site provided by the National Geological Service (NGS) helped to ensure the adaptability and safety of the TSF. The results of the analyses confirmed that the TSF is fully capable of coping with the movement of local strata and preventing the risk of tailings liquefaction, providing assurance of the robustness of the project.
此外,美国国家地质局 (NGS) 提供的矿区地质数据的全面分析有助于确保 TSF 的适应性和安全性。分析结果证实,TSF 完全有能力应对当地地层的移动并防止尾矿液化的风险,为项目的稳健性提供了保证。
In addition, this report recommends that the construction and subsequent operation of the project be based on long-term stability. The design of the tailings impoundment places great emphasis on strict control of construction quality and material properties, which is achieved through a layered compaction process and an effective drainage system. The commitment to quality is further demonstrated by comprehensive monitoring, environmental restoration and multi-level risk assessments, all of which are critical to preventing potential hazards, managing extreme weather events and maintaining an ecological balance during operations.
此外,本报告建议项目的建设和后续运营应建立在长期稳定性的基础上。尾矿蓄水池的设计非常强调对施工质量和材料特性的严格控制,这是通过分层压实过程和有效的排水系统实现的。全面监测、环境恢复和多层次风险评估进一步证明了对质量的承诺,所有这些都对于预防潜在危害、管理极端天气事件和在运营期间保持生态平衡至关重要。
Introduction
介绍
In this project, the design scope of the tailings storage facility (TSF) covered a variety of aspects, including dam structure design, material selection, construction methods, ecological restoration and risk management. The project needed to ensure that a facility capable of safely storing approximately 7 million cubic metres of tailings was constructed within a rectangular area measuring 1 kilometre by 1 kilometre while meeting the required 0.7-metre freeboard requirement. The design work not only had to take into account the short-term construction objectives of the tailings storage facility but also had to ensure its stability and safety in long-term operation, a commitment that was a top priority throughout the project.
在这个项目中,尾矿储存设施 (TSF) 的设计范围涵盖了多个方面,包括大坝结构设计、材料选择、施工方法、生态恢复和风险管理。该项目需要确保在 1 公里 x 1 公里的矩形区域内建造一个能够安全储存约 700 万立方米尾矿的设施,同时满足所需的 0.7 米干舷要求。设计工作不仅必须考虑到尾矿储存设施的短期建设目标,还必须确保其长期运行的稳定性和安全性,这是整个项目的重中之重。
The primary design objective of the project was to construct a cost-effective, safe, reliable, and environmentally friendly tailings storage facility. The dam was constructed using layers of in-situ sand and slag to optimise material utilisation, reduce construction costs, and ensure the structural stability of the dam. The project design was aligned with the mine operator's requirements, ensuring that the tailings were deposited in a manner consistent with the previous gold mine. This alignment allowed for the continuation of the existing tailings management and operations model, providing a sense of continuity and security to the stakeholders.
该项目的主要设计目标是建造一个具有成本效益、安全、可靠和环保的尾矿储存设施。大坝使用原位沙和矿渣层建造,以优化材料利用、降低施工成本并确保大坝的结构稳定性。项目设计符合矿山运营商的要求,确保尾矿的沉积方式与以前的金矿一致。这种一致性允许现有的尾矿管理和运营模式继续存在,为利益相关者提供连续性和安全性。
During the design process, several constraints need to be considered, including geological conditions, spatial constraints and material properties. Firstly, the tailings impoundment had to be constructed to suit the unique geological conditions of the Yilgarn Craton area, ensuring that the dam would be able to cope with the potential impacts of ground movement. Secondly, the project area was constrained to a 1km by 1km rectangle, requiring a design that maximised tailings storage capacity within a limited space. In addition, the performance and long-term stability of the construction materials posed a design challenge, particularly when considering the performance of the in-situ sand and mine waste rock under varying moisture and compaction conditions and the need to ensure their stability throughout the life of the tailings storage facility.
在设计过程中,需要考虑几个约束条件,包括地质条件、空间约束和材料属性。首先,尾矿蓄水池的建造必须适应 Yilgarn Craton 地区独特的地质条件,确保大坝能够应对地表移动的潜在影响。其次,项目区域被限制在 1 公里 x 1 公里的矩形内,要求在有限的空间内最大限度地提高尾矿储存能力。此外,建筑材料的性能和长期稳定性也带来了设计挑战,尤其是在考虑原位沙子和矿山废石在不同水分和压实条件下的性能,以及确保它们在尾矿储存设施整个生命周期内的稳定性时。
In addition, the design team was committed to weighing construction, operational, and environmental considerations. This commitment ensured the tailings impoundment operated safely and minimised its impact on the surrounding ecosystem. The project was designed to comply with local and international environmental standards and regulations, demonstrating our dedication to sustainability.
此外,设计团队还致力于权衡施工、运营和环境因素。这一承诺确保了尾矿蓄水池的安全运行,并最大限度地减少了对周围生态系统的影响。该项目的设计符合当地和国际环境标准和法规,展示了我们对可持续发展的奉献精神。
Theoretical Background
理论背景
Understanding the fundamentals of seepage, slope instability, and tailings storage configuration is not just critical, but it is the cornerstone of ensuring the stability and safety of tailings storage facilities (TSFs) in the design and construction process. This section will not just briefly review but also provide a comprehensive understanding of the relevant theoretical background of these critical factors, empowering it with the knowledge to support subsequent analyses.
了解渗流、边坡不稳定性和尾矿储存配置的基础知识不仅至关重要,而且是在设计和施工过程中确保尾矿储存设施 (TSF) 稳定性和安全性的基石。本节不仅将简要回顾,还将提供对这些关键因素的相关理论背景的全面理解,使其具备支持后续分析的知识。
Seepage Flow
渗流
Seepage in tailings impoundments involves water movement through the tailings and the dam, which has important implications for structural integrity. The main theoretical framework for understanding seepage is Darcy's Law, which shows that the water flow rate is proportional to the hydraulic gradient. Controlling seepage is particularly important to prevent erosion, pipe surges or internal instability within the dam.
尾矿蓄水池的渗漏涉及水流经尾矿和大坝,这对结构完整性具有重要影响。理解渗流的主要理论框架是达西定律,该定律表明水流速与水力梯度成正比。控制渗漏对于防止大坝内的侵蚀、管道浪涌或内部不稳定尤为重要。
Seepage analyses typically employ numerical methods like finite element analysis to simulate water flow and predict pore water pressures in tailings impoundment structures. Effective drainage systems, such as filters and drainage layers, can control seepage and reduce pore water pressures, thereby preventing failure mechanisms such as pipe surges or slope instability
渗流分析通常采用有限元分析等数值方法来模拟水流并预测尾矿蓄水结构中的孔隙水压力。有效的排水系统,如过滤器和排水层,可以控制渗漏并降低孔隙水压力,从而防止管道浪涌或边坡失稳等故障机制.
Slope Instability
边坡失稳
Slope instability is one of the main risks of tailings storage dams, and slope stability failure can lead to catastrophic consequences such as tailings leakage. The stability of slopes is usually assessed by the limit equilibrium method, which calculates a factor of safety (FoS) by comparing the resisting force (shear strength of the material) with the driving force (gravity, pore water pressure). A commonly used theory to describe the shear strength of soil or tailings materials is the Moore-Cullen criterion, which is influenced by cohesion, angle of internal friction and effective stress.
边坡失稳是尾矿库坝的主要风险之一,边坡稳定性失效会导致尾矿泄漏等灾难性后果。边坡的稳定性通常通过极限平衡法进行评估,该方法通过比较阻力(材料的剪切强度)与驱动力(重力、孔隙水压)来计算安全系数 (FoS)。描述土壤或尾矿材料剪切强度的常用理论是 Moore-Cullen 准则,该准则受内聚力、内耗角和有效应力的影响。
Slope stability analyses require consideration of various factors, including material properties, dam geometry, and external conditions such as seismic activity or rainfall. Using a tool such as GEOSTUDIO, critical sliding surfaces can be identified, and thus, the risk of slope instability can be assessed under normal and extreme conditions
边坡稳定性分析需要考虑各种因素,包括材料特性、大坝几何形状和外部条件,例如地震活动或降雨。使用 GEOSTUDIO 等工具,可以识别关键的滑动表面,从而可以评估正常和极端条件下边坡不稳定的风险.
TSF Configurations
TSF 配置
The configuration of a tailings impoundment significantly impacts its overall stability and seepage behaviour. Typical tailings impoundment configurations include upstream, downstream, and centreline dams, each with unique characteristics. For example, downstream dams are more stable because each new dam layer is built on top of a compacted tailings layer, whereas upstream dams, although less costly, face a greater risk of instability under seismic or heavy rainfall conditions.
尾矿蓄水池的配置对其整体稳定性和渗流行为有重大影响。典型的尾矿蓄水配置包括上游、下游和中心线坝,每个都有独特的特性。例如,下游大坝更稳定,因为每个新的大坝层都建在压实的尾矿层之上,而上游大坝虽然成本较低,但在地震或强降雨条件下面临更大的不稳定风险。
In this tailings storage design, the dam structure consists of layered stacks of native sand and mine waste rock, with particular attention to seepage control and slope stability. The design must meet long-term storage requirements, ensuring that the dam can support the expected volume of tailings (7 million cubic metres) and maintain structural integrity throughout the life of the tailings storage. The configuration chosen should balance economics with stability requirements.
在这个尾矿储存设计中,大坝结构由原生沙子和矿山废石的分层堆积组成,特别注意渗流控制和边坡稳定性。设计必须满足长期储存要求,确保大坝能够支持预期的尾矿量(700 万立方米),并在尾矿储存的整个生命周期内保持结构完整性 。选择的配置应平衡经济性和稳定性要求。
In summary, the theoretical understanding of seepage, slope stability and tailings storage configuration forms the basis for subsequent detailed analyses. Proper control of these factors ensures the long-term safety and functionality of tailings impoundments
总之,对渗流、边坡稳定性和尾矿储存配置的理论理解构成了后续详细分析的基础。对这些因素的适当控制确保了尾矿蓄水池的长期安全性和功能性.
Soil Testing and Interpretation
土壤测试和解释
This section describes several data that have been obtained prior to the design of the project, describes their sources, and shows their respective limitations.
本节介绍在项目设计之前获得的几个数据,介绍它们的来源,并展示它们各自的局限性。
Soil sample data for materials available for dams
大坝可用材料的土壤样本数据
According to the information provided by Client A, there are three types of dam materials that can be used for this project: the in-situ sand, mine waste rock (hereinafter referred to as rock) and clay, and the following two tables are given to illustrate the soil parameters of the different soil samples.
根据客户 A 提供的信息,本项目可以使用的坝体材料有三种类型:原位砂、矿山废石(以下简称岩石)和粘土,下面给出两个表格来说明不同土壤样本的土壤参数。
Table 1. Properties of material available for constructing the TSF
表 1.可用于构建 TSF 的材料特性
Table 2. Results of particle size distribution tests carried out on the materials available on site
表 2.对现场可用材料进行的粒度分布测试结果
Both parameters are obtained by collecting field soil samples and returning them to the laboratory to undergo the appropriate experiments. It should be noted, therefore, that laboratory tests are essential for determining soil material properties such as permeability, compaction, shear strength, and particle size distribution, but laboratory data are objectively susceptible to variations from field data. However, while laboratory tests are more accurate under controlled conditions, they may not fully reflect field variability. Specifically, the sample size and homogeneity of the material tested may not be representative of large-scale field conditions. In addition, field conditions such as water table fluctuations and construction techniques may also affect the actual performance of materials
这两个参数都是通过收集田间土壤样本并将其送回实验室进行适当的实验而获得的。因此,应该注意的是,实验室测试对于确定土壤材料特性(如渗透性、压实度、剪切强度和粒度分布)至关重要,但实验室数据客观上容易受到现场数据变化的影响。然而,虽然实验室测试在受控条件下更准确,但它们可能无法完全反映场变化。具体来说,被测材料的样品量和均匀性可能无法代表大规模的现场条件。此外,地下水位波动和施工技术等现场条件也可能影响材料的实际性能.
Tailings CPT data
尾矿 CPT 数据
With respect to the primary object of interest in this report, the tailings and its soil sample data were obtained from on-site CPT test data from another mine site that has been mined in the vicinity of the mine. Briefly, CPTu testing measures soil resistance by pushing a cone into the ground, which is calculated to provide valuable data on soil stratification and strength. For this tailings impoundment project, the CPTu test showed changes in soil stratification, highlighting areas of weaker ground that required additional reinforcement
就本报告的主要关注对象而言,尾矿及其土壤样本数据是从矿山附近开采的另一个矿场的现场 CPT 测试数据中获得的。简而言之,CPTu 测试通过将锥体推入地下来测量土壤阻力,该测试经过计算以提供有关土壤分层和强度的宝贵数据。对于这个尾矿蓄水项目,CPTu 测试显示了土壤分层的变化,突出了需要额外加固的薄弱地面区域.
Chart 1 Tailing CPTu results
图 1 尾矿 CPTu results
However, as with laboratory data, field testing has limitations and can still be affected by weather conditions, site accessibility and equipment limitations. In addition, the variability of soils over large areas means that test results from specific locations may not be fully representative of the entire site.
然而,与实验室数据一样,现场测试也有局限性,并且仍然会受到天气条件、现场可达性和设备限制的影响。此外,大面积土壤的可变性意味着来自特定位置的测试结果可能无法完全代表整个场地。
Seismic data in the region
该地区的地震数据
By consulting the PGA maps provided by the Seismological Commission of Australia, it is clear that the Yilgarn Craton area, where the mine is located, has a PGA value of 0.05 g (Earthquakes@GA., 2024). This value is similar to that common to the vast majority of the State of Western Australia, and therefore it is further assumed that the highest seismicity that could be expected to hit the area would be a magnitude of 6.0 on the Richter Scale (AustraliaStandards, 2018)
通过查阅澳大利亚地震委员会提供的 PGA 地图,很明显,矿山所在的 Yilgarn Craton 地区的 PGA 值为 0.05 克(Earthquakes@GA,2024 年)。该值与西澳大利亚州绝大多数地区的常见值相似,因此进一步假设预计袭击该地区的最高地震活动将是里氏 6.0 级(AustraliaStandards,2018 年).
Design Basis and Assumption
设计基础和假设
This report on the design of a tailings storage facility (TSF) for a gold mine located in the Yilgarn Craton region of Western Australia interlinks a number of critical factors and forms the basis of the design approach covered in the report. This section then provides an overview of the design fundamentals, including material selection, geotechnical considerations and operational constraints, followed by a discussion of common assumptions made during the design process
这份关于位于西澳大利亚州 Yilgarn Craton 地区的金矿尾矿储存设施 (TSF) 设计的报告将许多关键因素联系起来,并构成了报告涵盖的设计方法的基础。然后,本节概述了设计基础知识,包括材料选择、岩土工程注意事项和操作限制,然后讨论了设计过程中做出的常见假设.
Design Codes and Guidelines
设计规范和指南
The TSF has been designed in recognition of the following pertinent codes and guidelines:
TSF 的设计考虑了以下相关规范和指南:
The Code of Practice for Tailings Storage Facilities in Western Australia (DMP, 2013) administered by DMIRS.
由 DMIRS 管理的 西澳大利亚尾矿储存设施操作规范(DMP,2013 年)。
The Australian National Commission on Large Dam’s Guidelines on Tailings Dams; Planning Design, Construction, Operation and Closure (ANC, 2012)
澳大利亚国家大型大坝委员会的尾矿坝指南;规划设计、施工、运营和关闭 (ANC, 2012).
The Guide to the preparation of a design report for tailings storage facilities (DMP, Guide to the preparation of a design report for tailings storage facilities, 2015)
尾矿储存设施设计报告编制指南(DMP,尾矿储存设施设计报告编制指南,2015 年)
The (previous) Department of Minerals and Energy’s Guidelines on the Safe Design and Operating Standards for Tailings Storage (DME, 1999)
矿产和能源部关于尾矿储存安全设计和操作标准的指南(DME,1999 年).
AS 1170.4-2007. Structural design actions Earthquake actions in Australia (Reconfirmed 2018) (AustraliaStandards, 2018)
AS 1170.4-2007 年。结构设计行动 澳大利亚地震行动 (2018 年再次确认) (AustraliaStandards, 2018)
Design Basis
设计基础
The primary design objective of the tailings impoundment was to store approximately 7 million cubic metres of tailings in a rectangular area measuring 1 kilometre by 1 kilometre. Based on the operational and safety requirements, several criteria were established during the design process as follows:
尾矿蓄水池的主要设计目标是 在 1 公里 x 1 公里的矩形区域内储存约 700 万立方米的尾矿。根据操作和安全要求,在设计过程中建立了几个标准,如下所示:
Free Height Requirement: The tailings impoundment must maintain a free height of at least 0.7 metres under maximum operating conditions to prevent overflow. This free height takes into account the possible accumulation of water due to rainfall and helps to avoid the risk of tailings spills.
自由高度要求:在最大操作条件下,尾矿蓄水池必须保持至少 0.7 米的自由高度,以防止溢流。这个自由高度考虑到了降雨可能造成的积水,有助于避免尾矿溢出的风险。
GEOTECHNICAL CONDITIONS: The site is located within the ancient and stable Yilgarn Shield geological formation. Based on geological survey data, soil and bedrock conditions indicate a low seismic risk in the area, reducing the likelihood of tailings liquefaction but emphasising the importance of seepage control and slope stability measures.
岩土工程条件:该场地位于古老而稳定的 Yilgarn Shield 地质构造内。根据地质调查数据,土壤和基岩条件表明该地区的地震风险较低,降低了尾矿液化的可能性,但强调了渗流控制和边坡稳定性措施的重要性。
MATERIAL SELECTION: The dam will be constructed using in-situ sand and mine waste rock. To optimise material use and cost-effectiveness, a layered construction method will be used, with the mine waste rock providing core stability and the sand ensuring proper drainage.
材料选择:大坝将使用原位沙子和矿山废石建造。为了优化材料使用和成本效益,将采用分层施工方法,矿山废石提供核心稳定性,沙子确保适当排水。
Seepage control: Given the high permeability of the sand layer, drainage systems such as toe drains and filtration layers will be integrated into the design to manage seepage and avoid the build-up of pore water pressures within the dam, which could compromise stability.
防渗:鉴于沙层的高渗透性,设计中将整合排水系统,如脚排水管和过滤层,以管理渗漏并避免大坝内孔隙水压的积累,这可能会损害稳定性。
OPERATIONAL CONSIDERATIONS: The tailings impoundment will be constructed using similar tailings impoundment methods to those used at nearby gold mines. The operator will use thickened tailings to reduce water content and minimise the risk of failure associated with slurry flow. Continuous monitoring will be required throughout the life of the tailings impoundment to track critical parameters such as settlement and pore pressure
运营考虑:尾矿蓄水池将采用与附近金矿类似的尾矿蓄水方法建造。运营商将使用增稠的尾矿来降低含水量,并将与矿浆流动相关的故障风险降至最低。需要在尾矿蓄水池的整个生命周期内进行持续监测,以跟踪沉降和孔隙压力等关键参数.
Assumptions
假设
Design assumptions are critical for dealing with uncertainty and providing a practical framework for decision-making. The following key assumptions were made in this tailings storage project
设计假设对于处理不确定性和为决策提供实用框架至关重要。在这个尾矿储存项目中做出了以下关键假设:
Soil and Material Characteristics: It is assumed that the geotechnical characteristics of the in-situ sand and mine waste rock, such as shear strength, permeability, and compaction characteristics, will be consistent across the site; it is also assumed that the surface soil parameters established by the TSF will be consistent with the in-situ sand. This assumption simplifies the material selection and construction process, but field testing will be conducted to verify the assumption.
土壤和材料特性:假设原位沙子和矿山废石的岩土工程特性,例如剪切强度、渗透性和压实特性,在整个场地上是一致的;还假设 TSF 建立的表层土壤参数将与原位沙子一致。此假设简化了材料选择和施工过程,但将进行现场测试以验证该假设。
Seepage: Seepage in the dam is assumed to follow Darcy's Law, which sets a constant hydraulic gradient based on the tailings and dam configuration. The drainage system is expected to be able to handle seepage flows adequately and not result in significant pore water pressure build-up.
渗流:假设大坝中的渗流遵循达西定律,该定律根据尾矿和大坝配置设定恒定的水力梯度。排水系统应能够充分处理渗流,并且不会导致明显的孔隙水压力积聚。
Slope Stability: The dam slope design assumes a factor of safety of at least 1.5 under normal operating conditions and 1.3 during extreme events such as heavy rainfall or minor seismic activity. This conservative assumption ensures adequate margins against failure.
边坡稳定性:大坝边坡设计假设安全系数在正常运行条件下至少为 1.5,在极端事件(如强降雨或小型地震活动)期间为 1.3。这种保守的假设确保了足够的边际来防止失败。
Long-Term Material Degradation: It is assumed that the long-term performance of mine waste rock and sand will remain stable under environmental conditions. However, given the potential for weathering and material degradation, regular inspections and potential reinforcement measures are planned as part of the tailings storage maintenance strategy.
长期材料降解:假设矿山废石和沙子的长期性能在环境条件下将保持稳定。然而,考虑到潜在的风化和材料降解,作为尾矿储存维护策略的一部分,计划定期检查和可能的加固措施 。
Tailings Characterisation: The tailings material is assumed to have the same characteristics as tailings from nearby gold mines, extrapolated based on historical data. This includes similar particle size distribution, moisture content and shear strength, simplifying design and operational planning
尾矿特征:根据历史数据推断,假设尾矿材料与附近金矿的尾矿具有相同的特性。这包括相似的粒度分布、水分含量和剪切强度,从而简化了设计和操作规划.
Overall, the design of the gold mine tailings storage facility emphasises the integration of multiple considerations for the surrounding geotechnical analysis, material selection and operational considerations. Furthermore, this report builds on these design assumptions to provide a framework for assessment and design to manage uncertainties in soil properties, seepage control and long-term stability.
总体而言,金矿尾矿储存设施的设计强调整合了周围岩土工程分析、材料选择和运营考虑因素的多种因素。此外,本报告基于这些设计假设,为评估和设计提供了一个框架,以管理土壤特性、渗流控制和长期稳定性方面的不确定性。
Methodology
方法论
Basic theory and design methods and digital analysis tools
基本理论和设计方法以及数字分析工具
The design of a tailings storage facility (TSF) is highly dependent on an in-depth understanding of geotechnical engineering theory. One of the key theoretical concepts is the practical stress theory, which determines how stresses are transmitted through the soil and directly affect the stability of the tailings dam body. Closely related to this is the understanding of pore water pressure, which is an essential factor in assessing the potential for liquefaction and instability under static and dynamic conditions. Slope stability analyses, a key component in TSF design, are typically performed using the limit equilibrium method (LEM) and the finite element method (FEM) to identify potential destabilisation mechanisms and to assess the safety of the dam body under different loading conditions.
尾矿储存设施 (TSF) 的设计在很大程度上依赖于对岩土工程理论的深入理解。关键的理论概念之一是实用应力理论,它决定了应力如何通过土壤传递并直接影响尾矿坝体的稳定性。与此密切相关的是对孔隙水压力的理解,这是评估静态和动态条件下液化和不稳定可能性的重要因素。边坡稳定性分析是 TSF 设计的关键组成部分,通常使用极限平衡法 (LEM) 和有限元法 (FEM) 进行,以识别潜在的失稳机制并评估坝体在不同载荷条件下的安全性。
In terms of seepage analyses, Darcy's Law is the basis for understanding water flow in tailings and dam materials. Accurate seepage control is essential to prevent excessive pore water pressures, which may lead to a decrease in the stability of the dam. Filter layers and drainage systems are often introduced into the design to ensure that tailings impoundments remain stable during long-term operation.
在渗流分析方面,达西定律是了解尾矿和坝体材料中水流的基础。精确的渗流控制对于防止孔隙水压过大至关重要,这可能会导致大坝的稳定性降低。设计中经常引入过滤层和排水系统,以确保尾矿蓄水池在长期运行期间保持稳定。
Specifically, this report uses tools such as GEOSTUDIO (including modules such as SEEP/W & SLOPE/W.) that make it possible to perform detailed numerical simulations of seepage and slope stability. These tools are able to simulate complex real-world conditions, including the effects of phased construction, tailings-dam interactions, and the response of structures to extreme climatic events such as heavy rainfall or seismic activity.
具体来说,这份报告使用了如GEOSTUDIO(包括像SEEP/W和SLOPE/W这样的模块)的工具,使得对渗流和边坡稳定性进行详细的数值模拟成为可能。这些工具能够模拟复杂的真实条件,包括分阶段施工的影响、尾矿坝相互作用以及结构对极端气候事件(如强降雨或地震活动)的响应。
For example, with SEEP/W, this report simulates infiltration flow in a TSF, which in turn identifies areas of high pore water pressure and assesses the effectiveness of drainage design. Meanwhile, there is also SLOPE/W to help analyse slope stability and assess potential sliding surfaces and their safety margins in detail.
例如,使用 SEEP/W,该报告模拟 TSF 中的渗透流,进而识别高孔隙水压区域并评估排水设计的有效性。同时,还有 SLOPE/W 来帮助分析边坡稳定性并详细评估潜在的滑动表面及其安全裕度。
In addition to this, specialist geological calculation sheets are utilised to assist in the calculation and assessment of tailings liquefaction resistance.
除此之外,还使用专业的地质计算表来协助计算和评估尾矿的抗液化性。
Verification of the instability in seepage and pipe
V渗流和管道不稳定的
This report completes the verification of the instability in seepage and pipe surges by using GEOSTUDIO as follows:
本报告使用 GEOSTUDIO 完成对渗流和管道浪涌不稳定性的验证,如下所示:
Defining the geometric model
定义几何模型
Create a 2D or 3D geometric model of the tailings storage facility (TSF). Include the dam body, foundation layer and upstream and downstream areas.
创建尾矿储存设施 (TSF) 的 2D 或 3D 几何模型。包括坝体、基础层以及上游和下游区域。
Key in material parameters
关键材料参数
Input the permeability coefficient, volumetric water content curve (SWCC), saturated/unsaturated permeability and other parameters of each material layer.
输入各物料层的渗透系数、体积含水率曲线 (SWCC)、饱和/非饱和渗透率等参数。
Setting boundary conditions
设置边界条件
Upstream, set the water table height to simulate water storage or rainfall conditions.
在上游,设置地下水位高度以模拟蓄水或降雨条件。
Downstream, a seepage outlet or free-drainage boundary is set to ensure a reasonable outlet for the water flow.
在下游,设置渗流口或自由排水边界,以确保水流的合理出口。
Seepage analysis
渗流分析
Run seepage simulations using SEEP/W to assess flow paths, free surface locations and pore water pressure distributions.
使用 SEEP/W 运行渗流模拟,以评估流路、自由表面位置和孔隙水压力分布。
Focus on the free surface and infiltration gradient, as high infiltration gradients are prone to pipe surges.
重点关注自由表面和渗透梯度,因为高渗透梯度容易出现管道喘振。
Pipe surge validation
管道喘振验证
Determine if there is a risk of pipe surges by analysing the infiltration gradient downstream of the dam, especially near the dam base.
通过分析大坝下游的渗透梯度,尤其是大坝底部附近,确定是否存在管道浪涌的风险。
Areas of high infiltration gradients may cause soil particles to move, triggering tube surges.
高渗透梯度区域可能会导致土壤颗粒移动,从而引发管涌。
Monitor the pore water pressure in the dam body to assess whether hydraulic action may lead to soil instability.
监测坝体中的孔隙水压力,以评估水力作用是否会导致土壤不稳定。
Analysis of results
结果分析
Output the results of seepage path, free surface location and pore water pressure distribution.
输出渗流路径、自由表面位置和孔隙水压力分布的结果。
If the infiltration gradient is found to be too high in a local area of the dam body, it may be necessary to enhance the drainage design or optimise the dam body material to reduce the risk of pipe surges.
如果发现坝体局部区域的渗透坡度过高,则可能需要加强排水设计或优化坝体材料,以降低管道浪涌的风险。
Model calibration and optimisation
模型校准和优化
Based on the results, adjust the design or optimise the impermeable structure to ensure that the seepage and pipe surge risks are within control.
根据结果,调整设计或优化防渗结构,以确保渗漏和管道浪涌风险得到控制。
Run the optimisation model and re-analyse until the design requirements are met.
运行优化模型并重新分析,直到满足设计要求。
Verification of the Slope stability
V边坡稳定性
This report completes the Verification of the Slope stability by using GEOSTUDIO as follows:
本报告使用 GEOSTUDIO 完成边坡稳定性验证,如下所示:
Defining the geometric model
定义几何模型
A two-dimensional geometric model of the tailings dam or slope is established to accurately represent the shape, slope, and different material layers of the slope.
建立尾矿坝或边坡的二维几何模型,以准确表示边坡的形状、坡度和不同的材料层。
Input material parameters
输入材质参数
Define the strength parameters of each material layer, such as cohesion, friction angle, and unit weight.
定义每个材料层的强度参数,例如内聚力、摩擦角和单位重量。
Setting boundary conditions
设置边界条件
Different boundary conditions are set according to the site conditions and design requirements, including external loads, groundwater level and pore water pressure.
根据现场条件和设计要求设置不同的边界条件,包括外部荷载、地下水位和孔隙水压力。
By importing SEEP/W seepage analysis results, the effect of pore water pressure on slope stability can be automatically applied.
通过导入 SEEP/W 渗流分析结果,可以自动应用孔隙水压力对边坡稳定性的影响。
Defining potential sliding surfaces
定义潜在的滑动表面
SLOPE/W automatically generates and searches for potential sliding surfaces by the Janbu method.
SLOPE/W 通过 Janbu 方法自动生成和搜索潜在的滑动面 。
Slope stability analysis
边坡稳定性分析
Run SLOPE/W to analyse the Factor of Safety (FOS), which is the ratio of the sliding force to the resistance to sliding.
运行 SLOPE/W 以分析安全系数 (FOS),即滑动力与滑动阻力的比率。
Analysis of results
结果分析
Key results such as the factor of safety and the location of potential sliding surfaces are output.
输出关键结果,例如安全系数和潜在滑动面的位置。
If the Factor of Safety is lower than the target value of 1.5, the slope design should be optimised by adjusting the material parameters, slope or adding reinforcement.
如果安全系数低于目标值 1.5,则应通过调整材料参数、坡度或添加钢筋来优化坡度设计。
Model optimisation
模型优化
Based on the results of the analysis, adjust the design optimisation model to reduce the landslide risk, e.g. by reducing the slope, adding drainage or using anti-slip piles.
根据分析结果,调整设计优化模型以降低山泥倾泻风险,例如减少坡度、增加排水系统或使用防滑桩。
Re-run the model to verify the effectiveness of the optimisation scheme.
重新运行模型以验证优化方案的有效性。
Validation of resistance to liquefaction
抗液化性验证
The sensitivity of the soil samples to cyclic liquefaction and static liquefaction was analysed using the Plewes method in conjunction with CPTu data and assumptions, and recommendations were made for the overall design (Torres-Cruz, 2021)
使用 Plewes 方法结合 CPTu 数据和假设分析土壤样品对循环液化和静态液化的敏感性,并对整体设计提出建议(Torres-Cruz,2021 年).
Result
结果
Draft Sample
草稿样本
Figure 1 Designing Draft
图 1 设计草稿
The design elevation of the dam is 7.8 metres with an additional freeboard margin of 0.7 metres, resulting in a CREST elevation of 8.5 metres.
大坝的设计标高为 7.8 米,额外的干舷边缘为 0.7 米,因此 CREST 标高为 8.5 米。
The total length of the dam is 27 metres and the Crest is 3 metres wide; the TSF is designed as a square storage area with a lower bottom edge length of 943 metres and a top design edge length of 952 metres, with a design capacity of 7,002,551 cubic metres.
大坝总长 27 米,坝顶宽 3 米;TSF 设计为方形存储区,下底边长 943 米,顶边长 952 米,设计容量为 7,002,551 立方米。
The theme of the dam is constructed from in-situ sand, with an additional mine waste rock as a Shell to enhance its landslide resistance. The left shell is 5 metres wide, the right shell is 8 metres wide and the cone is 14 metres wide.
大坝的主题是由原位沙子建造的,并增加了一个矿山废石作为外壳,以增强其抗滑坡能力。左壳宽 5 米,右壳宽 8 米 ,圆锥体宽 14 米。
Verification Results
验证结果
Figure 2 Dam Toe Seepage Instability Verification via GEOSTUDIO
图2 通过 GEOSTUDIO 验证坝脚渗流不稳定性
The GEOSTUDIO simulation shows that the maximum hydraulic slope drop (i) at the dam base is only 0.4. And the maximum allowable hydraulic slope drop (ic) can be calculated as follows:
GEOSTUDIO 仿真显示,坝基处的最大水力坡度落差 (i) 仅为 0.4。最大允许水力斜率下降 (ic) 可计算如下:
Thus, ; It is OK.
因此, ;还行。
Figure 3 Seepage Instability Verification via GEOSTUDIO
图3 通过 GEOSTUDIO 进行渗流不稳定性验证
The GEOSTUDIO simulation shows that there is a high hydraulic gradient near the right side of the dam at a height of 7.5 metres, which indicates that there is some risk of pipe failure. As a solution, it was decided to lay a drainage pipe every 10 metres to mitigate the potential pipe failure.
GEOSTUDIO 模拟显示,大坝右侧附近有 7.5 米高的水力坡度,这表明存在一些管道故障的风险。作为解决方案,决定每 10 米铺设一根排水管,以减少潜在的管道故障。
Figure 4 Slope Stability Verification via GEOSTUDIO
图4:通过 GEOSTUDIO 进行边坡稳定性验证
The GEOSTUDIO simulation shows that the slope stability of the dam body is good and meets the FoS design value of 1.5, which is a reasonable and effective design result.。
GEOSTUDIO仿真表明,坝体边坡稳定性良好,满足1.5的FoS设计值,是一个合理有效的设计结果。。
Chart 2 Tailing Seimic Parameter
图 2 尾矿 地震参数
Analysing the calculations using the Plewes method and related tables, it can be seen that the tailings themselves have a low sensitivity to static liquefaction, even for an earthquake of magnitude 6.0 on the Richter scale, with a high degree of design redundancy. However, the tailings are moderately sensitive to cyclic liquefaction, mainly at a depth of 10 metres, possibly due to abrupt changes in soil stratification at 10 metres below ground level. Although additional samples are required to revalidate this data, the tailings are sufficiently robust to the potential cyclic liquefaction risk associated with a 6.0 Richter scale earthquake.
使用 Plewes 方法和相关表格分析计算结果,可以看出,尾矿本身对静态液化的敏感性很低,即使对于里氏 6.0 级地震也是如此,具有高度的设计冗余。然而,尾矿对循环液化中度敏感,主要在 10 米深度,这可能是由于地面以下 10 米的土壤分层突然变化所致。尽管需要额外的样本来重新验证这些数据,但尾矿对与里氏 6.0 级地震相关的潜在周期性液化风险具有足够的抵抗力。
Recommendations
建议
While the above design results have largely met the project requirements, the following recommendations are made to safeguard the smooth progress of the project and the subsequent operational quality and risk management.
虽然上述设计结果已基本满足项目要求,但为保障项目顺利进行以及后续的运营质量和风险管理,我们提出以下建议。
Construction techniques and material properties
构造技术和材料特性
Layered construction and quality control: Considering the design concept of using in-situ sand and slag stone in layered stacking, the thickness, compaction and water content of each layer of material should be strictly controlled during construction to ensure the overall stability of the dam. It is recommended that a special quality inspection team be set up at the construction site to regularly test the compaction and water content to ensure that the construction quality meets the design requirements.
分层施工和质量控制:考虑到分层堆放采用原位砂石和矿渣石的设计理念,施工时应严格控制每层材料的厚度、压实度和含水量,以确保大坝的整体稳定性。建议在施工现场成立专门的质检组,定期检测压实度和含水率,确保施工质量符合设计要求。
Construction of Emergency Drainage System: During the construction of the dam, it is recommended that an effective drainage system be constructed synchronously to avoid the accumulation of water under extreme rainfall conditions or during the construction process, resulting in dam instability or pipe surge failure. Facilities such as drainage ditches and infiltration pipes can be installed on the downstream side of the dam to direct the discharge of seepage and rainwater.
应急排水系统的建设:在大坝建设过程中,建议同步建设有效的排水系统,以避免在极端降雨条件下或施工过程中积水,导致大坝失稳或管道喘振失效。可以在大坝的下游侧安装排水沟和渗透管等设施,以引导渗水和雨水的排放。
Long-term stability of material performance: It is recommended that the performance of in-situ sand and mine waste rock under long-term compaction and moisture changes be further assessed at the design stage to ensure that the performance of the materials will not be degraded by environmental changes throughout the operation of the tailings impoundment. If necessary, the resistance to compression and erosion can be enhanced by the addition of stabilisers or other materials.
材料性能的长期稳定性:建议在设计阶段进一步评估原位砂和矿山废石在长期压实和水分变化下的性能,以确保材料的性能在整个尾矿运行过程中不会因环境变化而退化蓄水。如有必要,可以通过添加稳定剂或其他材料来增强抗压缩和抗侵蚀性。
Operations management and maintenance
运营管理和维护
It is recommended that slope stability monitoring equipment, such as inclinometers and surface deformation monitoring devices, be installed after construction is completed to detect and prevent potential landslide risks in a timely manner. In addition, vegetation cover or the use of erosion control nets may be considered for the surface layer of the slope to reduce the impact of wind and water erosion.
建议在施工完成后安装边坡稳定性监测设备,如测斜仪和地表变形监测装置,以便及时发现和预防潜在的滑坡风险。此外,可以考虑对斜坡的表层进行植被覆盖或使用侵蚀控制网,以减少风和水侵蚀的影响。
In addition, a comprehensive monitoring system should be established during the operation of the tailings storage facility to monitor parameters such as dam settlement, displacement, seepage volume, surface cracks, etc., to ensure the long-term stability of the dam. It is recommended that key monitoring points be inspected in detail at least quarterly and that timely maintenance measures be taken based on the monitoring results.
此外,在尾矿储存设施运行期间,应建立全面的监测系统,监测坝体沉降、位移、渗流量、表面裂缝等参数,确保坝体的长期稳定性。建议至少每季度对重点监控点进行详细检查,并根据监控结果及时采取维护措施。
Conclusion
结论
For the design of the Tailings Storage Facility (TSF) for this project, we undertook a comprehensive design and analysis of 7,000,000 cubic metres of tailings located in the Yilgarn Craton region of Western Australia. Through detailed theoretical background studies, materials testing, design basis assumptions and the application of numerical analysis tools, we reached the following key conclusions:
为了设计该项目的尾矿储存设施 (TSF),我们对位于西澳大利亚州 Yilgarn Craton 地区的 7,000,000 立方米尾矿进行了全面设计和分析。通过详细的理论背景研究、材料测试、设计基础假设和数值分析工具的应用,我们得出了以下关键结论:
Seepage and slope stability: Using GEOSTUDIO's SEEP/W and SLOPE/W modules, we successfully simulated the seepage behaviour and slope stability of the TSF. The results show that the design solution is effective in controlling seepage, reducing the risk of pipe surges and ensuring slope stability under normal operating conditions. Our design takes into account the worst-case seepage and landslide risks and optimises the stability of the facility through appropriate material configuration and slope design.
渗流和边坡稳定性:使用 GEOSTUDIO 的 SEEP/W 和 SLOPE/W 模块,我们成功地模拟了 TSF 的渗流行为和边坡稳定性。结果表明,该设计方案在控制渗流、降低管道喘振风险和确保正常运行条件下的边坡稳定性方面是有效的。我们的设计考虑了最坏情况下的渗漏和山泥倾泻风险,并通过适当的材料配置和斜坡设计来优化设施的稳定性。
MATERIAL TESTING AND LIMITATIONS: Laboratory and field soil testing provided critical data for the design. Although the test results have limitations to some extent (e.g., sample representativeness and effects of experimental conditions), we have fully considered these limitations in the design and ensured the reliability and practicality of the design by making reasonable assumptions and adjusting the material parameters.
材料测试和限制: 实验室和现场土壤测试为设计提供了关键数据。尽管测试结果在一定程度上存在局限性(例如,样品代表性和实验条件的影响),但我们在设计中充分考虑了这些局限性,并通过做出合理的假设和调整材料参数来确保设计的可靠性和实用性。
Design Basis and Assumptions: We set reasonable design parameters and assumptions based on the existing geological conditions and design specifications during the design process. These assumptions include the slope of the dam, the thickness of the material layer and the setting of the drainage system. All design parameters have been checked in detail to ensure that they are in line with the actual conditions and engineering requirements.
设计基础和假设:我们在设计过程中根据现有的地质条件和设计规范设定合理的设计参数和假设。这些假设包括大坝的坡度、材料层的厚度和排水系统的设置。所有设计参数都经过详细检查,以确保它们符合实际情况和工程要求。
Recommendations and Follow-up: To ensure the long-term stability and safety of the TSF, we recommend continued monitoring and maintenance of the facility during construction and operation, especially under extreme weather conditions. It is also recommended to further optimise the drainage system and slope stability measures to address potential seepage and landslide risks. In addition, regular disaster simulation drills and updating of the contingency plan are also necessary to improve the response to emergencies.
建议和跟进:为确保 TSF 的长期稳定性和安全性,我们建议在建设和运营期间持续监测和维护设施,尤其是在极端天气条件下。此外,还建议进一步优化排水系统和斜坡稳定性措施,以应对潜在的渗漏和山泥倾泻风险。此外,定期进行灾害模拟演习和更新应急计划对于提高对紧急情况的响应也是必要的。
Overall, through comprehensive design and analysis, we have provided a scientific and reliable design solution for the TSF project, which ensures the safety and stability of the tailings storage facility and lays a solid foundation for the smooth implementation of the project.
总体而言,通过全面的设计和分析,我们为TSF项目提供了科学可靠的设计方案,确保了尾矿储存设施的安全稳定,为项目的顺利实施奠定了坚实的基础。
Reference
Department of Mines and Petroleum. (2013). Code of practice for tailings storage facilities in Western Australia. Department of Mines, Industry Regulation and Safety.
矿业和石油部。(2013). 西澳大利亚尾矿储存设施操作规范。 矿业、工业监管和安全部。
Australian National Commission on Large Dams. (2012). Guidelines on tailings dams: Planning, design, construction, operation, and closure. Australian National Committee on Large Dams.
澳大利亚国家大型水坝委员会。(2012). 尾矿坝指南:规划、设计、施工、运营和关闭。 澳大利亚大型水坝国家委员会。
Department of Mines and Petroleum. (2015). Guide to the preparation of a design report for tailings storage facilities. Department of Mines, Industry Regulation and Safety.
矿业和石油部。(2015). 尾矿储存设施设计报告准备指南。 矿业、工业监管和安全部。
Department of Minerals and Energy. (1999). Guidelines on the safe design and operating standards for tailings storage. Department of Minerals and Energy.
矿产和能源部。(1999). 尾矿储存安全设计和操作标准指南。 矿产和能源部。
Standards Australia. (2018). AS 1170.4-2007: Structural design actions: Earthquake actions in Australia (Reconfirmed 2018). Standards Australia.
澳大利亚标准。(2018). AS 1170.4-2007:结构设计行动:澳大利亚的地震行动(2018 年再次确认)。 澳大利亚标准。
Earthquakes@GA. (n.d.). Retrieved September 08, 2024 from https://earthquakes.ga.gov.au/
Earthquakes@GA(日期不详)。2024 年 9 月 8 日从 https://earthquakes.ga.gov.au/ 检索
Torres-Cruz, L. A. (2021). The Plewes Method: A Word of Caution. Mining, Metallurgy & Exploration, 38, 1329–1338. https://doi.org/10.1007/s42461-021-00392-0​:contentReference[oaicite:0]{index=0}​:contentReference[oaicite:1]{index=1}
洛杉矶托雷斯-克鲁兹(2021 年)。Plewes 方法:一句警告。采矿、冶金与勘探,38,1329-1338。 https://doi.org/10.1007/s42461-021-00392-0​:contentReference[oaicite:0]{index=0}​:contentReference[oaicite:1]{index=1}