某尾矿坝稳定性分析

以某尾矿库为实例,分析尾矿的沉积规律和尾矿坝的稳定性。假定地下水流网为简单方格型,坝体为均质,针对坝体堆积现状标高和设计终期标高,分别考虑正常运行和洪水运行2种工况,用瑞典圆弧法和简化Bishop法分别进行稳定性计算。根据计算成果分析危险滑弧的分布规律和2种方法所得安全系数的差异。指出为了得出准确的计算结果,需要全面收集资料,建立符合实际的模型,采用合理的计算参数,进行现场浸润线和孔隙水压力监测。     

细粒尾矿特性研究及其堆坝工程实践

细粒尾矿的堆存问题是尾矿处理遇到的技术难题之一。在总结以往研究的基础上,以云南某尾矿库为背景开展细粒尾矿特性研究。首先,阐述了尾矿库因入库尾矿粒度细,导致出现筑坝困难、坝体排渗不畅、沉积滩坡度缓、稳定性差等问题;其次,从堆坝工艺、降低浸润线及坝体稳定性三方面综合考虑,提出了以模袋法堆积子坝、三维立体排渗盲沟、铺设土工格栅等为核心的细粒尾矿堆坝技术;最后,通过典型工程案例分析,论证了该技术在细粒尾矿处置中的有效性和合理性。该成果对于今后细粒尾矿库的设计、施工以及运行管理等具有指导意义。     

基于属性识别理论的降雨诱发尾矿坝失稳动态评价模型研究

考虑到不同降雨条件对尾矿库坝体稳定性影响的差异性,为提高尾矿库坝体稳定性评估的可靠性和准确度,引入属性识别理论,建立了不同降雨条件下尾矿库坝体稳定性动态评估模型。首先,从工程、管理、地质、降雨4个方面选取了13个典型指标,构建了尾矿库坝体稳定性综合评价指标体系,并确定了指标分级标准;其次,应用G1法确定了5种降雨条件下的动态指标权重,根据指标分级情况建立了单指标属性测度函数,并计算综合属性测度值,基于属性识别准则评估稳定性等级;最后,以广东省云浮市某尾矿库为例,运用所建立的综合评价模型进行尾矿库坝体稳定性动态评估。结果显示:随着降雨强度增大,各指标权重呈现非线性动态变化特征,尾矿坝稳定性等级也随之降低,数学评价模型与专家讨论结论相一致,表明建立的动态评价模型可适应于尾矿坝稳定性评价。     

神经网络预测尾矿沉积规律的方法

基于神经网络特性，探讨了用于预测尾矿库沉积滩上尾矿颗粒沉积规律神经网络的设计，并将其用于某尾矿沉积滩沉积规律的预测，说明神经网络用于预测尾矿的沉积规律是可行的。     

基于Geo-Studio的降雨条件下尾矿坝体稳定性分析

为研究降雨对尾矿坝体稳定性影响,以广东云浮某尾矿库为例,应用Geo-Studio软件,基于极限平衡理论的简化Bishop法,计算强降雨和连续降雨2种工况条件下的尾矿坝体最小安全系数,评估尾矿坝体稳定性状态。结果显示：2种工况条件下尾矿坝体最小安全系数均大于尾矿库安全规程明确的最小安全系数,表明该尾矿坝体稳定性满足生产要求,不存在重大生产安全事故隐患。结合工程实际,提出了简要的工程建议。     

某尾矿坝边坡稳定性计算与安全分析

介绍了边坡稳定性的分析方法和研究现状。引进理正岩土软件,建立某尾矿库2D仿真模型,阐述理正岩土软件在尾矿坝边坡稳定性计算与安全分析中的应用,采用Fellenius法、简化Bishop法、Janbu法对某尾矿坝坝体稳定性进行计算。计算结果表明该坝体在正常运行条件下是安全稳定的。应用结果表明将理正岩土软件应用到矿山领域完全可行。     

基于GEO-Studio的某尾矿坝动力稳定性分析

针对某尾矿坝动力稳定性问题,基于尾矿库实测地形图与岩土地层勘察资料,依据地形概化的方法,建立反映尾矿库地形、地质结构特征的数值计算模型。运用GEO-Studio的QUAKE分析模块进行现状及最终尾矿坝动力稳定性分析,研究了该尾矿坝在地震波作用下的液化情况、加速度响应、位移变化、安全系数的规律,研究结果表明,该尾矿坝可在洪水工况下稳定运行,可以作为工程设计的参考依据。     

尾砂分级综合利用对尾矿库安全稳定的影响

开展尾砂分级综合利用是当下矿山资源综合利用的趋势。研究尾矿分级粒径的选取对尾矿库安全稳定的影响问题,并阐明获得科学合理的尾矿分级粒径取值的技术路径。结果表明：尾矿分级取走一定数量的粗粒尾矿对尾矿堆积筑坝及尾矿库排洪的安全稳定性产生一定的影响,如果尾砂分级粒径选取不合理,取走的粗粒尾矿数量超过安全范围,造成细粒(包括黏性)尾砂占比增加,可能导致尾矿堆积坝出现渗透变形破坏,严重时甚至会造成尾矿坝坍滑失稳;同时可能导致尾矿沉积滩面坡度变缓,减少尾矿库的调洪库容,降低尾矿库的排洪安全性。研究获得安全合理的尾矿分级粒径取值对于尾矿库的安全稳定性至关重要。为了实现这一目标,必须以尾矿库的安全(包括尾矿坝的稳定安全和尾矿库的排洪安全)为中心展开一系列的研究论证工作,才能确保尾砂分级粒径取值的科学、合理。主要研究内容包括：研究分级后的尾矿物理力学特性变化情况、尾矿沉积滩平均坡度变化情况,以及尾砂粒径改变之后,对尾矿坝沉积分布规律产生的影响;基于多种工况条件,重新进行尾矿坝渗流分析计算、尾矿库调洪演算和尾矿坝稳定分析计算,必要时还需要进行尾矿库溃坝试验研究。研究成果可指导国内外尾矿分级综合利用工程技术实...     

洪水工况下某尾矿坝动力稳定性分析

对四川某高堆尾矿库地质勘查资料进行整理,合理概化了坝体主轴剖面,采用等效黏弹性模型,对处于洪水工况下的该尾矿坝用GeoStudio有限元软件进行数值模拟研究,研究了该尾矿坝在EI Centro地震波作用下的反应加速度、位移变化、液化范围、安全系数、动力稳定性的规律,研究结果显示该尾矿坝可在洪水工况下稳定运行,为其他尾矿坝的动力稳定性分析提供参考。     

用模糊综合评价法评估铀水冶厂尾矿库应急能力

通过分析铀水冶厂尾矿库应急要素,构建了应急能力评估三级指标体系;运用模糊综合评价法评估铀水冶厂尾矿库的应急能力并构建评估模型,采用层次分析法和Delphi法对各级评估指标进行赋权,并选取某铀水冶厂尾矿库进行实例应用检验,得出的评估结果基本上可反映该尾矿应急能力的实际情况。     

PSO优化算法在尾矿库空间预测中的应用

由于尾矿库的空间变异特殊性,传统的插值法预测精度不高,误差很大。为解决这一问题,考虑到粒子群算法在求解非线性问题时具有更强的全局搜索能力、并行性和多样性、适应性和自适应性,提出了一种基于粒子群算法优化Kriging模型来拟合尾矿库内部参数数据的克里格空间预测算法,旨在提高尾矿库内部参数信息的拟合精度,减少误差。为验证改进算法的有效性,采用多种预测评价指标进行分析,并与传统Kriging进行交叉验证分析,确定优化算法的可靠性。结果表明：相比于传统的加权最小二乘法拟合法,采用PSO算法拟合 Kriging 模型参数时,内摩擦角平均误差率降低了23.36%,黏聚力平均误差率降低了8.45%,证明算法可行和有效。     

Numerical Study of the Effects of Drainage Systems on Saturated/Unsaturated Seepage and Stability of Tailings Dams

The stability of tailings dams is affected by seepage characteristics such as the location of the phreatic surface inside the dam, the effects of the capillary fringe, and the unsaturated zone above the zero pore pressure level. In this study, the performance of drainage systems in tailings dams was investigated by analyzing saturated and unsaturated seepage in the dam, considering the effects of the construction method, tailings properties, and the type of drainage systems. First, general seepage characteristics in tailings dams were studied and the effects of non-homogeneity were investigated. Our results show that in a silty tailings dam with a height of 15 m, unsaturated plus capillary seepage flux can reach 13% of the total seepage. The total head vs. discharge volume curves under various conditions were compared and their practical implications are presented. Then, stability analyses were carried out using the results of seepage analyses for different construction methods, material properties, and drainage systems. Finally, a number of practical conclusions are drawn regarding dam stability and the efficiency of toe, blanket, and chimney drains in different construction methods. Using a blanket and/or a chimney drain can increase the stability safety factor by up to two times, depending on the type of material.     

强降雨条件下某铅锌矿尾矿堆积坝安全稳定性分析

强降雨是影响尾矿坝安全的重要因素之一,同时尾矿堆积坝在建造的过程中随着选矿工艺的改变堆坝尾砂的粒径分布也随之变化。为了研究不同组构尾矿堆积坝在强降雨条件下的稳定性,以湖南某铅锌矿尾矿堆积坝为研究对象,在分析该尾砂坝各级堆积子坝的尾矿砂物理力学性质的基础上,采用数值模拟方法研究了该尾矿坝在强降雨作用下不同时期堆积子坝的稳定性。研究表明:1)不同高度堆积子坝的尾砂组构不同,其不均匀系数、曲率系数以及黏聚力不同,尾矿堆积坝的安全系数与尾砂黏聚力呈正相关关系,与尾砂的不均匀系数呈正比,与曲率系数呈反比;2)相同降雨强度,降雨时长的增加对尾矿堆积坝整体稳定性影响小,但对坝坡表面及一定深度的尾砂有影响,其负孔隙水压力减小,坝体松散,影响坝坡稳定;3)尾矿堆积坝各部位能承受的最大剪应变与尾砂的黏聚力呈正相关关系,且黏聚力大的坝体的最大剪应变在各个区域都较黏聚力小的坝体有较大剪应变。实际堆积坝施工过程中可通过尾砂组构来分析坝体在强降雨作用下的稳定性。     

How to Prevent Flow Failures in Tailings Dams

Based on research carried out at 67 tailings dams in Spain: (1) tailings dams contain alternating sedimentary layers with contractive and dilative geomechanical behaviours; (2) tailings saturate quickly but drain more than 10 times slower due to the high-suction capacity of the porous sediments (2–300 MPa); and (3) over the long-term, a stationary flow regime is attained within a tailings basin. Four temporal and spatial conditions must all be present for a tailing dams flow failure to occur: (1) the tailings must experience contractive behaviour; (2) the tailings must be fully saturated; (3) the effective stress due to static or dynamic load must approach zero; and (4) the shear stress must exceed the tailings residual shear stress. Our results also indicate that the degree of saturation (S_r) is the most influential factor controlling dam stability. The pore-pressure coefficient controls geotechnical stability: when it exceeds 0.5 (S_r = 0.7), the safety factor decreases dramatically. Therefore, controlling the degree of tailings saturation is instrumental to preventing dam failures, and can be achieved using a double drainage system, one for the unconsolidated foundation materials and another for the overlying tailings.

     

Reinforced terraced fields method for fine tailings disposal

New mining technologies can exploit low-grade ores but they produce high volumes of waste, such as tailings. Further, current mineral processing techniques produce more and more fine tailings. How to dispose of these tailings is a key issue in the sustainable operation of a mine. A traditional method is to construct a settling or tailings pond for storage. Such a method requires sufficient coarse particles to raise a dam or embankment. However, the fine tailings contain little coarse particles and have poor mechanical properties. The stability of a tailings dam thus becomes a major issue if the traditional method is used. According to statistical data, all fine tailings dams or ponds in China have failed or have failure potential. Therefore, fine tailings disposal is a challenge to mine operators and new disposal methods should be explored for the stability improvement of tailings dams. In this paper, an innovative method of reinforced terraced fields is presented to satisfy the specific requirement of fine tailings disposal. By using an actual mine, this paper reports in detail the design concept and procedures for this method. Its feasibility is evaluated and its fundamental are analyzed.     

饱和尾矿稳态特性研究

饱和尾矿的稳态强度和变形特性是尾矿坝能否发生流滑破坏的关键因素,通过试验充分了解尾矿的稳态特性是尾矿坝稳定性评价的重要内容。以江西九江某尾矿坝体的尾矿为对象,进行三轴固结不排水剪切试验,研究饱和尾矿的稳态特性。结果表明：饱和松散尾矿的三轴固结不排水剪切曲线具有明显的软化特性,曲线软化程度随围压的增大而减小,同一围压下孔隙比越小软化现象越不明显。根据试验结果建立尾矿的稳态线,论证了稳态是尾矿的固有属性,即稳态线具有唯一性。指出稳态内摩擦角是尾矿变形最终可动用的有效内摩擦角,并求出尾矿稳态内摩擦角。     

Stability analysis of a copper tailings dam via laboratory model tests: A Chinese case study

The upstream method is a popular method for raising tailings dams. Currently in China there are more than 12,000 tailings impoundments and almost 95% of them use the upstream method for the construction of the dam. Statistical data has shown that the tailings impoundment is one of the main sources of risk in the mining industry. Failures of tailings impoundments have resulted in the loss of many lives, considerable property damage, and irreversible pollution in downstream areas. Therefore, the safety of tailings management facilities has been of increasing concern to governments and local communities. The management of a conventional tailings storage facility requires the maintenance of a high level of structural stability. Therefore, according to the relevant mine Acts, the mine operators are required to conduct stability analyses for all types of tailings facilities, whether they are new, active, or decommissioned. For the stability analysis of tailings dams, the accurate profile of the tailings dam is very important. The profiles are easily obtained for both active and decommissioned tailings facilities because their data can be collected through field investigations. However, collecting basic data from newly constructed tailings facilities is difficult. In this paper, a laboratory physical model test has been performed. The construction process for new tailings impoundment has been physically simulated in the laboratory, where the tailings particle composition and distribution below a beach, the change of phreatic surface of the dam, and the engineering properties of the tailings of the dam profiles have been measured. A new tailings facility, Yangtianqin tailings impoundment, owned by Tongchang copper mine of Yuxi Mine Co., was used as a case study to illustrate the physical modeling of the tailings dam. In the model test, the geometrical model of pond area was constructed according to the scale factor, λ_L, of 1:200 (model:prototype), and the tailings discharge system was also established, the tailings slurry then being discharged based on the design data. Finally, on the basis of the model test results on profiles, the stability analysis of the tailings dam at different heights was conducted under different conditions. The model test results and stability analysis show that the height of the tailings dam should be less than that originally planned. The original design of Yangtianqing tailings impoundment should therefore be revised for the safety of the tailings impoundment.     

Effects of Nonhomogenity of Permeability on Tailings Dams

This paper has the objective of showing the influence of the permeability gradient during the construction of tailings dams, built by the upstream method, using the hydraulic fill technique. During the hydraulic disposition, two mechanisms affect the tailings permeability: the hydraulic segregation and the consolidation due the staged construction procedure. These mechanisms influence considerably the permeability distribution along the fill and, consequently, the behaviour of the dam. Results show that the pore pressure immediately after deposition may reach quite high values (532 kPa), but dissipates in a short period of time (1 to 10 days). Then, this effect should be taken into account in a short-term stability analysis of tailings dams. On the other hand, after pore pressure dissipation, there is a gain in the shear strength (13 %), which should also be considered, but in a long-term stability analysis of tailings dams.     

基于强度折减法的尾矿库渗流稳定性分析

尾矿库在渗流条件下的稳定性是影响整个矿山安全的重要因素。本文以国内某上游法堆筑尾矿库为研究对象,采用强度折减法对尾矿库在渗流条件下的稳定性进行了系统的分析,对比了不同失稳判别准则在尾矿库稳定性分析中的适用性和局限性,提出了以初期坝附近尾砂出现指向坝外、向上的变形矢量为标志的"变形矢量图准则"。研究结果表明,基于强度折减法进行尾矿库稳定性分析时,采用"变形矢量图准则"可以更准确高效地获得尾矿库的稳定安全系数。     

细粒尾矿堆积坝的地震稳定性分析

在分析地震对尾矿坝造成破坏特点的基础上，介绍了尾矿坝地震稳定性分析方法。以龙都尾矿库细粒尾矿堆积坝为例，分析了在当地发生七级地震情况下，尾矿坝在不同状态下的结果，为矿山进行尾矿库的安全管理提供了科学依据。