深覆盖层面板堆石坝应力应变分析

发布时间：2018-03-17 02:37

本文选题：混凝土面板堆石坝　切入点：深覆盖层　出处：《兰州交通大学》2014年硕士论文　论文类型：学位论文

【摘要】：混凝土面板堆石坝由于其广泛的适应性，较高的安全性和较好的经济性而被广泛应用于工程实际。随着堆石坝的广泛运用，在我国已有很多深覆盖层上建坝的工程实例，对深覆盖层混凝土面板堆石坝的应力变形问题的研究探讨就显得尤为重要。本文全面介绍了面板堆石坝的发展历程，研究现状，并从深覆盖层建坝的特点出发，以察哈乌苏混凝土面板堆石坝为例，研究了深覆盖层上建坝对坝体的应力变形的影响。通过多方面的比较，邓肯张的E-B模型由于其模型参数代表的物理意义相对较明确，且应力应变关系曲线与实测曲线拟合性较好，故文章选取邓肯张的E-B模型作为堆石体本构模型，并对其进行详细的介绍。文章建立了察哈乌苏混凝土面板堆石坝三维有限元模型，采用有限元分析方法，利用ANSYS软件对坝体分级施工和加载进行了模拟，并选取了三个坝体典型剖面，对竣工期、死水位和正常蓄水位三种工况下的坝体和面板的应力、变形进行了分析。通过分析得出：竣工期，坝体大、小主应力对应的最大受拉区都在上游坝体与厚覆盖层接触的坝尖处，大主应力对应的最大受压区则位于坝体的二分之一处对应的厚覆盖层的最底端。沿着坝坡方向，面板大体处于受压状态，，且底部的压应力较大，但在坝顶及岸坡附近出现较小的拉应力；岸坡两侧面板主要发生顺流方向的位移，且位移值很小，而河床段面板发生了较大的逆流方向位移。故竣工后面板会出现一定的鼓起和脱空。蓄水之后，坝体大、小主应力对应的最大受拉区和最大受压区的位置都变化不大，由于水压力的影响，面板出现一定程度的弯曲变形，面板所受拉应力和压应力都随着水位的增加而增大，但压应力的增幅明显大于拉应力。总体上，蓄水后由于面板传递的水压力作用，坝体逆流位移有明显减小，而顺流位移有所增加，最大逆流位移位置上移至面板与趾板连接处正下方30m左右覆盖层处。受到水压力的作用，面板的顺流位移出现大幅度的增加，逆流位移则有所减小，脱空现象消失。总体上，三种工况下大主应力呈不对称分布，上游坝体所受压应力明显大于下游；小主应力的分布呈略偏上游的对称分布。通过分析，通常在深覆盖层面板坝的面板与趾板连接处出现最大拉应力，故在面板施工时，应该做好面板与趾板的连接与接缝处理。由于面板在竣工期会出现一定的隆起脱空现象，因此要求混凝土面板具有一定的抵抗弯曲变形的能力。
[Abstract]:Concrete face rockfill dam is widely used in engineering practice because of its wide adaptability, high safety and good economy. It is very important to study the stress and deformation of deep overburden concrete face rockfill dam. In this paper, the development history and present situation of the concrete face rockfill dam are introduced. Based on the characteristics of the deep overburden dam, the paper takes Chahawusu concrete face rockfill dam as an example. The influence of dam construction on the stress and deformation of the dam body in deep overburden is studied. Through the comparison of various aspects, the E-B model of Duncan Chang is relatively clear because of the physical meaning of its model parameters. The stress-strain relationship curve fits well with the measured curve, so this paper chooses Duncan Chang's E-B model as the constitutive model of rockfill and introduces it in detail. In this paper, the three-dimensional finite element model of Chahawusu concrete face rockfill dam is established. By using the finite element analysis method and ANSYS software, the construction and loading of the dam body are simulated, and three typical sections of the dam body are selected for the completion period. The stress and deformation of dam body and face slab under three working conditions of dead water level and normal storage water level are analyzed. It is concluded that the maximum tension area corresponding to large dam body and small principal stress is located at the top of the dam in the upper reaches of the dam body in contact with thick overburden layer. The maximum compression region corresponding to the large principal stress is located at the bottom of the thick overburden corresponding to 1/2 points of the dam body. Along the direction of the dam slope, the face slab is generally in the state of compression, and the compressive stress at the bottom is large. However, there are small tensile stresses near the dam top and bank slope, and the displacement in the downstream direction is mainly observed on both sides of the bank slope, and the displacement value is very small. However, the face slab of the river bed has a large countercurrent displacement. After completion, there will be a certain bulging and emptying of the face slab. After water storage, the position of the maximum tension zone and the maximum compression area corresponding to the large dam body and the small principal stress will not change much, and the position of the maximum tension area and the maximum compression area will not change much after the completion of the dam. Due to the influence of water pressure, the face slab appears a certain degree of bending deformation. The tensile stress and compressive stress of the face plate increase with the increase of water level, but the increase of compressive stress is obviously larger than that of tensile stress. After water storage, the countercurrent displacement of the dam body decreases obviously due to the effect of the water pressure transmitted by the face slab, while the downstream displacement increases, and the position of the maximum countercurrent displacement moves up to the cover layer about 30 m below the joint of the face slab and the toe plate, which is affected by the water pressure. The downstream displacement of the face slab increases by a large margin, the countercurrent displacement decreases, and the void phenomenon disappears. In general, the large principal stress is distributed asymmetrically under three working conditions, and the compressive stress of the upstream dam body is obviously larger than that of the downstream dam body. The distribution of small principal stress is slightly upstream symmetrical distribution. Through analysis, the maximum tensile stress usually appears at the joint of the face slab and toe slab of the deep overburden face slab dam, so in the construction of the face slab, The connection and joint treatment between the slab and the toe slab should be done well. Due to the phenomenon of uplift and void in the completion period of the concrete slab, it is required that the concrete slab has the ability to resist bending and deformation.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV641.43

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