某尾矿库在地震作用下的坝体动力稳定性研究

发布时间：2019-04-20 12:15

【摘要】：尾矿库是用来贮存金属、非金属矿山进行矿石选别后排出尾矿的场所,其下游经常会有村庄、厂矿、农田等重要设施,如果在外部或内部因素下尾矿库遭到破坏进而发生溃坝事故,将会给下游群众造成巨大损失。同时,我国是一个多地震国家,地震又是导致尾矿库溃坝的一个重要因素。因此,本文以河北省承德市砬子沟尾矿库为研究对象,主要进行了以下的地震作用下尾矿坝动力稳定性研究工作:(1)对该尾矿库的基本情况进行了描述和总结,详细叙述了库区地质条件和地震效应,并选取了两个断面进行稳定分析。(2)在坝体静应力分析中,采用增量法考虑土料的非线性性质,土料的应力—应变关系采用邓肯—张双曲线E-v模型。针对尾矿库选取的两个断面选取了八种工况,用有限元软件计算出了每个断面不同工况下的最大主应力σ_1、最小主应力σ_3、剪应力τ_(xy)、水平位移和垂直位移云图,根据不同工况下的计算结果可判断坝体在静力作用下处于稳定状态。(3)采用时域上的Wilson-θ逐步积分法按照等价线性化法进行动力分析,输入的地震波中选取2条实测地震波和1条人工合成地震波,在两个不同断面四种不同工况下利用有限元软件计算坝体X、Y方向节点加速度,最大和最小主应力以及X-Y动剪应力的动力响应云图,可以看出坝顶和库表面水平加速度反应最大,坝体垂直加速度反应在坝体表面最大。为了得出加速度、动剪应力和位移随时间的变化趋势,在同样的工况下分别绘制相应的时程图。可以看出加速度和动剪应力刚开始比较小,往后有越来越大的趋势,而且地震对坝体位移影响很大,最大位移出现在坝坡约3/4高度处。(4)在尾矿砂动力特性试验与地震动力反应分析的基础上,针对选取的两个断面以及四种工况下,计算出在同一断面上同一工况下相对紧密度的数值大小对坝体断面可能的液化区分布范围的影响。分别用Elcentro波、Taft波和人工合成地震波对尾矿库进行了液化分析,三种波计算出的液化区分布规律相似,计算结果没有明显离散,表明地震波选取的合理性,同时表明了计算程序的稳定性。通过有限元软件计算出两个断面中每个断面在三种不同地震波作用下的永久变形图可确定震后发生残余变形后尾矿库的最小安全超高和最小干滩长度满足规范的要求。(5)总结了尾矿库发生溃坝事故的危险因素和主要原因,提出了加强现场管理工作措施,并建立了有效的管理制度,保障尾矿库的长期安全稳定。
[Abstract]:Tailings reservoir is used to store metal, non-metallic mines for ore separation after the discharge of tailings, the downstream of which will often have villages, factories, mines, farmland and other important facilities. If the tailings reservoir is destroyed under the external or internal factors and then the dam break happens, it will cause great losses to the downstream masses. At the same time, China is a multi-earthquake country, earthquake is an important factor that leads to tailing dam break. Therefore, taking Lazigou tailing reservoir in Chengde City, Hebei Province as the research object, this paper mainly studies the dynamic stability of tailing dam under the action of earthquake: (1) the basic situation of the tailing dam is described and summarized. The geological conditions and seismic effects of the reservoir area are described in detail, and two sections are selected for the stability analysis. (2) in the static stress analysis of the dam body, the nonlinear properties of the soil are considered by the incremental method. Duncan-Chang hyperbolic model is used to describe the stress-strain relationship of soil. The maximum principal stress 蟽 _ 1, minimum principal stress 蟽 _ 3 and shear stress 蟿 _ (xy), of each section under different working conditions are calculated by using finite element software according to the two sections selected in tailing reservoir under eight working conditions. The maximum principal stress 蟽 _ 1, the minimum principal stress 蟽 _ 3, and the shear stress 蟿 _ stress are calculated by finite element software. The horizontal displacement and vertical displacement cloud diagram can be used to judge that the dam body is stable under the static action according to the calculated results under different working conditions. (3) the dynamic analysis is carried out by the Wilson- 胃 step-by-step integration method in the time domain according to the equivalent linearization method. In the input seismic wave, two measured seismic waves and one synthetic seismic wave are selected. Under four different conditions of two different sections, the acceleration of the joints in the X and Y direction of the dam body is calculated by finite element software. The maximum and minimum principal stress and the dynamic response cloud diagram of the dynamic shear stress show that the horizontal acceleration response of the dam top and reservoir surface is the largest, and the vertical acceleration response of the dam body is the largest on the dam body surface. In order to obtain the changing trend of acceleration, dynamic shear stress and displacement with time, the corresponding time-history diagrams are drawn under the same conditions. It can be seen that the acceleration and dynamic shear stress are relatively small at first, and there is an increasing trend in the future, and the earthquake has a great influence on the displacement of the dam body. The maximum displacement occurs at the height of about 3 ~ 4 on the dam slope. (4) on the basis of the test of dynamic characteristics of tailings and the analysis of seismic dynamic response, according to the selected two sections and four working conditions, The influence of the numerical value of relative compact density on the possible distribution range of the liquefied zone in the dam cross-section is calculated under the same section and the same working condition. The liquefaction analysis of tailing reservoir is carried out by using Elcentro wave, Taft wave and synthetic seismic wave respectively. The distribution of liquefaction zone calculated by three kinds of waves is similar, and the calculated results are not obviously discrete, which indicates that the selection of seismic wave is reasonable. At the same time, the stability of the program is shown. The permanent deformation map of each cross section in the two sections under the action of three different seismic waves can be calculated by finite element software. The minimum safe superelevation and minimum dry beach length of the tailing reservoir after residual deformation after the earthquake can be determined to meet the specifications. Requirements. (5) the risk factors and main causes of dam break in tailings reservoir are summarized. Measures to strengthen on-site management are put forward, and effective management system is established to ensure long-term safety and stability of tailing depots.
【学位授予单位】：石家庄铁道大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD926.4

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