排渗墙技术及排渗效果分析

对于初期坝为土坝的的尾矿库,后期随着尾矿的堆高,很容易造成坝坡渗水。现有的排渗设施———盲沟、管井、轻型井点、水平滤水孔、辐射井等可以起到一定效果,但不能大面积截断浸润线流线,没有解决悬挂水的影响,降水深度也不够理想。结合现有排渗措施提出排渗墙技术,经过工程实践表明,其有效性和可靠性均大幅提高。     

气驱排渗技术及其在膏体尾矿筑坝工程的应用

果郎沟尾矿库为甲玛铜多金属矿二期工程配套尾矿库,采用初期坝+膏体上游法堆坝形式,实际运行过程中存在尾砂渗透系数低、不固结,且坝体浸润线埋深仅10 m左右等问题.华泰龙矿业公司采用气驱排渗技术,在坝体均匀布设特殊结构的竖直和水平排渗管,采用高压气驱和重力自流的联合排渗方式,大大提高了坝体排渗效率,浸润线埋深快速降低至20...     

Evaluation of Seepage from an Embankment Dam Retaining Fly Ash

Observations, data, and analyses used to investigate the cause of fly ash-laden seepage from the right abutment of an earthen dam are presented herein. The investigation shows that the sediment-laden seepage occurred through permeable/jointed bedrock in the right abutment that was exposed by a landslide prior to construction of the dam. When the level of the impounded fly ash reached the level of the prior landslide, the fly ash-laden seepage migrated through the jointed bedrock of the abutment and exited on the downstream right abutment. The joint bedrock was exposed to the fly ash reservoir because the landslide removed the clayey colluvium and/or residual soil overlying the jointed bedrock that formed a natural impervious barrier to seepage. This sediment-laden seepage initially was a great concern because of the potential for erosion and piping in earth dams. However, the rapid investigation into and subsequent monitoring of the seepage revealed that accumulation of fly ash and other coarser particles created a filter cake that reduced the seepage and eventually sealed the joints and fractures in the sandstone abutment. No fly ash-laden seepage has been observed on the downstream abutment since April 2004 after first appearing on February 16, 2004. This filter cake development and self-healing process averted additional seepage and illustrates the beneficial effects of fly ash-laden seepage in controlling reservoir leakage.     

某钨矿尾矿库坝体渗水治理实践

某钨矿尾矿库坝体渗水严重,存在很大的安全隐患。通过对尾矿库岩土工程地质特征、土层渗透性、坝体渗流计算分析以及初期坝坝坡渗水原因分析,提出在初期坝坝面和排渗棱体顶部各增设一排水平排渗管,将坝体内尾矿渗透水及时引至坝坡排水沟后再排往下游,降低坝体内浸润线,以增强坝体稳定性。治理后初期坝坝面水平排渗管日最大排渗量696 m3,排渗棱体顶部水平排渗管日最大排渗量1 326 m3,解决了坝坡渗水问题,标高200 m浸润线比治理前降低了0.99 m,保证了坝体的稳定与安全。     

Case Study: Finite Element Method and Artificial Neural Network Models for Flow through Jeziorsko Earthfill Dam in Poland

A finite element method (FEM) and an artificial neural network (ANN) model were developed to simulate flow through Jeziorsko earthfill dam in Poland. The developed FEM is capable of simulating two-dimensional unsteady and nonuniform flow through a nonhomogenous and anisotropic saturated and unsaturated porous body of an earthfill dam. For Jeziorsko dam, the FEM model had 5,497 triangular elements and 3,010 nodes, with the FEM network being made denser in the dam body and in the neighborhood of the drainage ditches. The ANN model developed for Jeziorsko dam was a feedforward three layer network employing the sigmoid function as an activator and the back-propagation algorithm for the network learning. The water levels on the upstream and downstream sides of the dam were input variables and the water levels in the piezometers were the target outputs in the ANN model. The two models were calibrated and verified using the piezometer data collected on a section of the Jeziorsko dam. The water levels computed by the models satisfactorily compared with those measured by the piezometers. The model results also revealed that the ANN model performed as good as and in some cases better than the FEM model. This case study offers insight into the adequacy of ANN as well as its competitiveness against FEM for predicting seepage through an earthfill dam body.     

尾矿膏体蠕动堆存技术在窄沟陡坡降雨集中尾矿库的应用

为解决高寒陡坡尾矿库下游式排放方式降雨集中季节在窄沟陡坡形成的泥石流冲击尾矿坝等问题,对高海拔尾矿库采用上游法排放尾矿,采用自高而下分台阶蠕动排放,修筑防汛缓冲子坝,实行全面防渗与排渗,以及边运行边复垦等有效措施,保证了降雨集中季节以及尾矿冻结融化过程中尾矿库运行的稳定性。     

两流板坯连铸58t中间包过滤器的水模型试验和应用

通过几何相似比0.29:1的水模型试验了湍流抑制器+挡墙+挡坝和湍流抑制器+挡墙+过滤器两种控流装置的钢液流动,研究了通道式过滤器对58t中间包钢液流场的影响。结果表明,原中间包（湍流抑制器+挡墙+挡坝）活塞区体积小,死区体积高达29.53%,优化中间包加入过滤器后（湍流抑制器+挡墙+过滤器）短路流基本消失,钢液的实际平均停留时间延长,死区体积由29.53%减小至13.52%。50t中间包,230mm×1100mm连铸板坯,拉速1.25~1.30m/min工业生产结果表明,使用过滤器后,中间包浇注区的夹杂物尺寸明显小于冲击区,中间包浇注区T[O]由原86×10^-6降至30×10^-6,连铸坯大多数夹杂物尺寸≤10μm,没有发现≥30μm夹杂物。     

某矿山尾矿库渗流电模拟试验研究

某矿山尾矿库三期扩建设计方案中,堆积高程为734 m时洪水运行的最小干滩长度不能满足要求。为了确定此堆积高程坝体逸出点位置及浸润线情况,进行了三组电模拟试验,即设计方案、管式排渗方案和铺设土工膜方案。试验结果表明,管式排渗和铺设土工膜均可有效地降低坝体浸润线,有利于尾矿库坝体的稳定。     

Some Uncertainties in Embankment Dam Engineering

In the design and construction of embankment dams, our current capability for precise mathematical analysis and modeling of induced stresses and deformations, or of potential seepage patterns, far exceeds our capability to make judgments of comparable accuracy concerning, for example, the site and geology or how the soil properties may be affected by the weather or by the contractor’s methods. In addition, there is often a lack of adequate communication between the design and the supervision of construction. These uncertainties or doubts about the actual performance of the dam when constructed are discussed in the paper and illustrated by case history examples, with particular reference to the uncertain effects of cold weather, to the use of broadly graded soils (tills) as core and to problems in the placement, and segregation of tills and filter materials.     

EH-4在堤坝渗漏探测中的应用

EH-4连续电导率成像系统是新一代数字化的电磁法仪器。分析了EH-4观测信号经离散傅里叶变换后,不同频率时长的傅立叶变换不可避免地产生信号频谱泄露。在分析和理解窗口函数特点及其作用的基础上,结合堤坝渗漏探测中对信号的分析与处理,确定了堤坝渗漏的空间位置,为帷幕灌浆提供了科学依据。     

尾矿库溃坝影响范围预测评价

尾矿库溃坝影响范围预测是金属矿山环境影响评价的重点,但目前尚没有系统、统一的评价方法,一般采用经验类比和经验公式推理分析估算确定。针对包气带渗透性强的开阔地区采用单沟泥石流经验预测公式和地下水对流扩散模式对尾矿库溃坝后泥石流覆盖范围和地下水影响范围及程度进行定量分析评价,得出了某尾矿库一旦溃坝后泥石流覆盖范围为坝下游58.15 hm2,事故发生4年后地下水最大超标范围2.4 km。该尾矿库溃坝影响范围预测评价,为同地区、同类型项目环境评价和环境管理者决策提供依据和参考。     

大口辐射井在尾矿库堆积坝排渗中的应用

In order to solve the problem that the saturation line of the dam body is shallow in the safety inspection of Dexing Copper Mine tailing dam of Jiangxi Copper Co., Ltd., and ensure the stability of the dam, the reasons for the shallow buried depth of the saturation line of the dam body are analyzed firstly. Then, considering the characteristics of different drainage methods of the tailings pond, combined with the actual situation of the No.2 tailings pond of Dexing Copper Mine, the addition of large radial wells and water is proposed through the establishment of seepage finite element calculation model, it is concluded that after adding large radial well and horizontal drainage layer, the buried depth of saturation line of tailings pond is obviously reduced, the influence range of large radial well is 128~184m, the elevation phreatic line is 5 ~ 12m lower than the current situation, and the average buried depth of phreatic line is 15m, which meets the design requirements under normal working conditions, the saturation line of the dam body is controlled to be 15m deep, which effectively ensures the stability of the dam body.     

泉水沟尾矿坝三维渗流分析及渗透稳定性研究

针对设计方案计算分析了4种干滩长度运行工况下的尾矿库渗流场分布情况以及坝体浸润线埋深规律,为尾矿坝的各种运行工况下的渗流场渗流量预测计算,提供了一个较合理的模型和本尾矿坝各部分的渗流计算参数,对坝体设计、排渗设施提出合理性建议。     

申家峪尾矿库三维渗流稳定分析与研究

为确保申家峪尾矿库坝体的安全稳定,根据尾矿库工程地质和水文地质的实际情况,对申家峪尾矿库的渗流条件进行了符合实际情况的假设,并建立了反映主要坝体结构和周边岩体特性的三维有限元模型。通过MIDAS/GTS NX计算软件的数值模拟,分析了尾矿坝终期标高340 m时正常工况下坝体的渗流特性和正常运行条件下的渗流情形;评价分析了尾矿库在终期堆积标高时的渗流稳定性,并为坝体抗滑稳定验算提供了准确的浸润面位置。通过工程分析证明,利用MIDAS/GTS NX计算软件可以较好地模拟尾矿库的渗流特性,对尾矿库的安全生产有一定的参考价值和指导意义。     

Column Test Studies of Ochre Biofilm Formation in Geotextile Filters

This paper presents a study of ochre formation in geotextile filters. Ochre is a substance found sticking to solid surfaces of drainage systems that may cause clogging. The accumulation of such materials in a drainage system may have undesirable implications, such as a decrease in drainage flow capacity and an increase in soil pore pressure; instability of soil masses and retaining systems; and alteration of the direction of flow and development of pipes. Ochre formation is the result of microbial activities on iron compounds naturally found in seepage water. Even though geotextiles have been widely used in drainage systems, very few studies have considered ochre formation in the tests. Laboratory column filter tests were conducted to simulate the ochre formation process under similar conditions to those in geotechnical works and to assess the long-term performance of a geotextile. Ochre is most likely to be formed at an aerated/nonaerated interface in the filter. In order to obtain this condition, the underneath face of the filters was opened to the atmosphere. Three different types of geotextile—nonwoven polyester, nonwoven polypropylene, and woven polypropylene—were used in the tests. Control tests were also conducted with a sand filter to provide a basis for comparison. Hydraulic conductivity changes and iron retention within the permeameters were monitored throughout the tests. Ochre was formed under the presence of iron ions and iron bacteria. During the test period, the filters were not clogged to such an extent as to induce a global reduction in the permeability of the drainage system. Nevertheless, at the end of the tests a considerable amount of ochre was found in all filters and there was a significant variation in the permeability of the geotextile filters when tested in isolation. These studies may contribute to discovering whether ochre can be considered as a biofilm, evaluating the clogging potential and defining mitigating measures.     

Seepage Modeling Assisted Optimal Design of a Homogeneous Earth Dam: Procedure Evolution

Presented herein is a procedure for arriving at an optimal design of a homogeneous earth dam laid on an impervious foundation and provided with a drain. The procedure, heavily dependent on variably saturated flow modeling, involves optimizing a multiobjective function comprising a weighted summation of four objective functions, viz., the dam section area, seepage discharge, wetted area of the dam section and the drain area. The design variables considered in the optimization are the upstream and downstream slopes and the drain dimensions. The optimization is carried out subject to the constraints ensuring safe upstream and downstream slopes and sufficient distance between the free surface and the downstream face. Two of the objective functions (viz., the seepage discharge and the wetted area) and the constraints are implicit functions of the design variables. Their values are obtained by employing a numerical model of two-dimensional (vertical plane) variably saturated flow in a homogeneous earth dam. Optimization, conducted by the sequential unconstrained minimization technique procedure is preceded by several runs of the model for various combinations of the design variables. The discrete values of the implicit functions so generated are invoked during optimization to compute the implicit objective functions and constraints. The results are presented in the form of nondimensional design tables/curves. The design procedure is illustrated with the help of few examples.     

带过滤器63t中间包钢液流场的物理和数学模拟

通过采用几何相似比0.29:1的水模型和数学模型分别对(a)湍流抑制器和挡墙+坝(原结构),(b)湍流抑制器,挡墙+坝和过滤器,以及(c)湍流抑制器,挡墙和过滤器3种结构两流板坯连铸中间包钢液流场、温度场和夹杂物运动轨迹进行模拟研究。结果表明,原中间包结构(a)活塞区体积偏小,死区体积偏大;加入通道式钢液过滤器(b)后短路流基本消失,中间包死区减小6.83%,钢液的平均停留时间由287.04 s延长至373.76 s,有利于夹杂物的上浮去除,且过滤器的加入对钢液的温降影响不大;用钢液过滤器代替挡坝(c)后优化效果最为明显,中间包钢液平均停留时间由287.04 s延长至404.26 s,峰值时间由原来的95,4 s延长至190.8 s,死区体积由36.10%减小至8.76%。     

某尾矿库渗漏水对地下水的影响分析

尾矿库在运行期间,坝基和坝身都可能存在一定的渗漏问题;渗透水中含有采矿、选矿过程的有害物质,会对地下水造成污染。文中针对某尾矿库的渗漏水对地下水的污染途径进行了详细分析,给出了渗漏水量计算模型、参数选择及污染趋势预测。通过分析知道,某尾矿库运行期间最大渗漏水量达27.9m^3／d,对区域地下水影响较小。     

某钽铌矿尾矿库闭库整治工程设计研究

某钽铌矿尾矿库即将库满停用,进入闭库程序。整治设计采取了沿坝轴线射水造混凝土防渗墙、翻修排水棱体和加设溢洪道消力池及钢筋混凝土护面等整治措施。经渗流及坝坡稳定等分析计算,表明设计采取的整治加固措施具有较好的效果,满足尾矿库安全要求。