几个尾矿坝垮塌事故的案例分析与教训

从国内外几个典型尾矿坝事故分析入手,就导致尾矿坝失事的原因进行论述,认为管理、洪水、渗透及液化等是导致尾矿坝失事的主要原因,从而阐述应吸取的教训。     

国外尾矿坝事故调查分析

尾矿设施是矿山生产要素的重要组成部分,同时也是潜在的危险源.伴随矿业工程的不断发展,尾矿坝事故屡有发生.尾矿坝溃坝事故不仅使尾矿流失,严重时还多破坏下游地区的生态环境,造成巨大的生命财产损失.通过调查1960年以来国外发生的较典型的80例尾矿坝事故,对事故发生的时间特征、地点分布特征、在不同矿山发生的频率特征进行了对比分析.从事故发生的特点看,许多溃坝事故发生在暴雨过后的短暂时间内.尾矿坝事故与地震的破坏作用和其他10种因素有关,而由于暴雨和地震原因产生的事故占40%以上.如果尾矿库位于河流附近,其地面坡度较大时,溃坝会使流体状态的尾矿以(8～40)km/h的速度向下游排泄,污染范围多达160 km.对地基强度不足、地震液化、库水位上升、渗流等不同作用机制下发生坝体破坏的主要模式进行了讨论.     

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。     

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.

     

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.     

基于DIC的含水尾砂堆积坝振动破坏研究

为探讨含水率对尾砂堆积坝振动破坏的影响,在室内直剪试验的基础上开展堆积坝模型振动台试验,结合数字图像相关技术(Digital Image Correlation Technology,DIC)研究了含水尾砂堆积坝的振动破坏规律、局部变形及损伤演化特征。试验结果表明:尾砂的黏聚力随含水率增大呈现先增大后减小趋势,并得到c-ω拟合公式,而内摩擦角变化较小,在30.03°～33.44°范围内波动;黏聚力对尾砂堆积坝稳定性和起裂时刻具有重要影响;坝体含水率对堆积坝破裂形态及破坏模式影响显著,高含水率16.0%坝体呈"局部单一式"拉伸破坏,低含水率5.6%坝体发生"交错溃散式"张拉—剪切复合型破坏,随着含水率增加,尾砂堆积坝振动破坏模式由拉剪破坏向张拉破坏主导过渡;基于局部应变场统计分析提出损伤因子定量表征坝面损伤,含水5.6%坝面损伤因子呈突发式增长趋势,呈现为脆性破坏,含水13.0%与16.0%堆积坝后期损伤因子增长缓慢,向延性破坏过渡。     

尾矿坝地质剖面概化及其对渗流场计算的影响

分析了上游堆筑法尾矿坝坝体尾矿砂分布特点，提出地质剖面概化原则，并对比分析了概化剖面对渗流场的影响。认为概化地质剖面，对于深入研究尾矿坝渗流规律和提出防渗排水工程措施是必需的，也是可行的。     

大型尾矿库坝排渗工程施工技术

以德兴铜矿2^#尾矿库坝排渗工程为例，系统、扼要地阐明了采用辐射井排渗系统降低坝体浸润线的加固方法。竣工后对排渗运行情况的检测与分析，证明了辐射井排渗使坝体浸润线水位整体明显下降。     

DAMSAT: An Eye in the Sky for Monitoring Tailings Dams

Mine Water and the Environment - During the past decade, there have been a number of catastrophic tailings dam failures. Affordable monitoring systems, as well as methods to assess the risk posed...     

击实对全尾砂固结体强度及渗透性影响

为了解决全尾砂固结体地面排放时堆排体稳定性的问题,提出通过击实来增大全尾砂固结体的稳定性.通过室内击实试验、无侧限抗压强度试验、常水头渗透试验和扫描电镜试验,研究了击实对全尾砂固结体无侧限抗压强度和渗透系数的影响以及微观层面上击实对固结体内部结构变化的影响.得到了不同击实功下的全尾砂固结体的最大干密度和最优含水率,并以此为基础研究了击实功(598.2 kJ/m3、1074.7 kJ/m3、1535.3 kJ/m3和2149.4 kJ/m3)、干密度、含水率和养护龄期对固结体无侧限抗压强度和渗透系数的影响.结果表明,无侧限抗压强度随击实功、干密度和养护龄期的增加而增大,随含水率的增加而减小;渗透系数随击实功、干密度和养护龄期的增加而增大.对固结体进行击实可以减少固结体内部结构的孔隙并提升固结体结构的密实度,从而提高了固结体的强度和抗渗性能.表明在全尾砂固结排放中,可以通过击实的手段提高全尾砂固结体的强度和抗渗性,进而提高全尾砂固结体的稳定性.     

尾矿砂结构特征对渗透性影响的数值模拟

为了探究尾矿砂结构特征对其渗透性的影响,以尾矿砂圆柱模型为研究对象,采用FLUENT对不同实验条件下的尾矿砂圆柱渗透系数进行数值模拟,验证了数值模拟方法在求解渗透系数时的有效性。通过研究不同结构特征因素对尾矿砂圆柱渗透系数的影响,得出了渗透系数和颗粒直径、孔隙率之间的规律。在孔隙率固定不变的情况下,渗透系数和颗粒直径的平方近似呈正比关系;在颗粒直径不变的情况下,渗透系数和孔隙率的三次方成正比关系。极差分析结果显示,颗粒直径是影响渗透系数较大的因素,次因为孔隙率,且两者的影响都表现出正相关性。     

The Use of Accurate Pore Pressure Monitoring for Risk Reduction in Tailings Dams

Mine Water and the Environment - Simply monitoring movement of the tailings dam wall does not address the cause of tailings dam failures and will therefore never be an effective method to reduce or...     

国内外尾矿坝事故致灾因素分析

通过搜集已有尾矿坝事故资料,分析了国内外尾矿坝事故与坝高、筑坝工艺及致灾因素的关系。对147起尾矿坝事故的分析研究表明,引起尾矿坝事故的主要因素为降雨,其次为地震、管理等;对国内的42起尾矿坝溃坝事故的致灾因素分析表明,引起尾矿坝溃坝事故的主要因素为坝体稳定性不足、违规建设、不寻常降雨等。     

Pyrite Flotation Separation and Encapsulation: A Synchronized Remediation System for Tailings Dams

Mine Water and the Environment - Pyrite flotation separation and encapsulation in tailings dams is proposed as a viable way to chemically stabilize tailings. Characterization of potential acid mine...     

酸碱溶液对含硫尾矿砂渗透特性的影响研究

为研究酸碱溶液作用下含硫尾矿砂渗透特性的变化规律,对采自辽宁阜新某尾矿库的含硫尾矿砂开展研究,测得不同p H值溶液入渗条件下尾矿砂的孔隙比、渗透系数等参数,研究了不同水化学环境条件下含硫尾矿砂渗透特性的变化规律。研究表明,经酸溶液入渗的尾矿砂在试验前24 h内,渗透系数显著增大,随着时间的增加,渗透系数逐渐降低至最小值;Na OH溶液处理后的尾矿砂渗透系数逐渐减小;经酸碱溶液入渗的尾矿砂的渗透系数均随着孔隙比的增大而逐渐增大,且各工况的渗透系数均呈现出先缓慢增长,后快速增加的变化趋势。研究成果将为尾矿坝的安全运行和稳定性分析提供重要参考价值。     

化学因素作用下某尾矿砂渗透特性及污染防治研究

尾矿作为矿山开采过程中不可避免的固体废弃物,其渗透(淋滤)特性是诱发环境污染的关键因素之一.以某铜矿山尾矿为例,采用自主设计的渗透(淋滤)装置,探讨了化学因素作用下不同干密度尾矿砂的渗透及淋滤特性,揭示了不同pH溶液环境下尾矿砂的渗透系数变化规律;针对尾矿淋滤对环境的污染现象,采用Visual MODFLOW数值软件,...     

A Tragic Disaster Caused by the Failure of Tailings Dams Leads to the Formation of the Stava 1985 Foundation

Abstract.   This paper summarizes the dynamics and causes of the Stava disaster, and highlights some risky design procedures that led to the 19 July 1985 tailings dam failure. It then presents the Stava 1985 Foundation, which was formed to focus attention on such risks and to strengthen the culture of respect for human lives and safety.     

超声波对浮选柱选钼过程中细粒尾矿再选的试验研究

较多研究结果表明超声波对硫化矿物的选别影响显著,文中选择河南某辉钼矿作为试验对象,将原工艺流程中精扫选I的尾矿作为试验给矿进行超声处理,同时检验超声波的去泥效果。采用正交试验方法研究超声波各因素对选矿效率的影响及各因素间影响的显著性,并通过单因素方差分析评价了超声波有无对钼选矿效率的影响显著性。研究还表明超声波去泥效果显著,精矿中+38μm矿物的含量比无超声时增加了20.22%。     

铀尾矿浸出液对蚕豆（Viciafaba）早期生长的影响

利用室内培养法研究了铀尾矿浸出液对蚕豆（Vicia faba）根尖细胞的微核率、核酸酶活性及对蚕豆种子萌发的影响．结果表明：铀尾矿浸出液达到一定剂量时均可引起蚕豆根尖细胞微核数增加，微核数随浓度增大而逐渐增多，说明铀尾矿对蚕豆幼苗具有明显的遗传毒性效应；铀尾矿对蚕豆种子的萌发率没有影响；铀尾矿促进幼苗的生长，低浓度比高浓度明显；低浓度铀尾矿浸出液对核酸酶有一定的激活作用，高浓度则抑制．当铀尾矿浸出液浓度逐渐增大时，抑制作用逐渐增强．图1，表4，参14．     

尾矿坝排渗设施中土工织物选用的渗透性准则

通过初步的试验研究，确定了有压和土工织物受污染情况下渗透系数会产生变化，提出了土工织物选用的渗透性公式Ｋｇ≥ηｓηｐＫｓ，最后讨论ηｓ、ηｐ的取值。