重力坝非线性有限元深层抗滑稳定分析中突变理论的应用研究

发布时间：2018-02-20 01:57

本文关键词： 重力坝深层抗滑稳定非线性突变理论失稳判据　出处：《太原理工大学》2014年硕士论文　论文类型：学位论文

【摘要】：通常情况下,坝基并不是完整的岩体,往往存在复杂的节理、裂隙以及断层等地质结构,当这些结构面贯通形成滑动通道时,将会造成重大工程事故,给人民的生命财产以及国家建设造成重大损失。因此,对重力坝深层抗滑稳定性的研究具有重要意义。近年来,我国许多学者针对重力坝深层抗滑稳定分析做了大量的研究。但重力坝坝基深层抗滑稳定是一个复杂的问题,至今仍未形成统一规范以及客观精准的理论评价方法,故需要进一步探讨与分析重力坝深层抗滑稳定问题。本文将突变理论应用于重力坝深层抗滑稳定分析中,利用ANSYS软件,采用非线性有限元强度折减法进行研究。本文的主要研究内容如下：首先,利用ANSYS软件,通过非线性有限元计算得到坝趾夹层处上下两点的节点号以及水平方向相对位移值,然后基于尖点突变理论,确定坝址夹层处上下两点的水平方向相对位移X与强度折减系数k的尖点突变模型势函数,进而将该尖点突变模型势函数转化为尖点突变模型的标准势函数,根据尖点突变理论得到重力坝失稳判据的判别式,通过计算标准势函数的极值点和拐点共轭条件集来判别重力坝是否失稳。其次,在清峪水库重力坝深层抗滑稳定分析过程中,采用非线性有限元强度折减法,得到各典型点水平方向位移—强度折减系数关系曲线,当以典型点位移突变作为失稳判据时,不同典型点所得到的安全系数并不唯一。然后,在进行清峪水库重力坝非线性有限元深层抗滑稳定分析时,根据计算结果,采用重力坝深层抗滑稳定的相对位移尖点突变模型失稳判据,此时得到的安全系数和采用常用的塑性区贯通失稳判据进行判别所得的结果相同,最后,采用双斜面法和三斜面法分别计算,将采用相对位移尖点突变模型失稳判据所得的计算结果同双斜面法和三斜面法的计算结果进行比较,计算结果相对误差较小,证明了重力坝深层抗滑稳定的相对位移尖点突变模型失稳判据在工程中的正确性和适用性。本文建立了坝趾夹层处的上下两点的水平方向相对位移—强度折减系数尖点突变模型,并将其作为失稳判据,可以体现重力坝失稳过程的突变性,能够将安全系数量化到一个客观具体的数值,同时结果具有唯一性。通过建立模型的标准势函数,并比较其判别式与零的大小关系来判断重力坝是否失稳,概念清楚,界定明确。
[Abstract]:Usually, the dam foundation is not a complete rock mass, and there are complex geological structures such as joints, fractures and faults. It has great loss to people's life and property and national construction. Therefore, it is of great significance to study the deep anti-slide stability of gravity dam. In recent years, many scholars in China have done a lot of research on the analysis of the deep anti-slide stability of gravity dam, but the deep anti-slide stability of gravity dam foundation is a complex problem, which has not yet formed a unified standard and objective and accurate theoretical evaluation method. Therefore, it is necessary to further discuss and analyze the problem of deep anti-slip stability of gravity dam. In this paper, the catastrophe theory is applied to the analysis of the deep anti-slip stability of gravity dams. The nonlinear finite element strength reduction method is used to study the stability of gravity dams by using ANSYS software. The main contents of this paper are as follows:. Firstly, using ANSYS software, the node number and horizontal relative displacement of the upper and lower two points in the dam toe intercalation are calculated by nonlinear finite element method, and then based on the cusp catastrophe theory, The potential function of the cusp catastrophe model of the horizontal direction relative displacement X and the strength reduction coefficient k of the upper and lower two points at the dam site is determined, and the potential function of the cusp catastrophe model is transformed into the standard potential function of the cusp mutation model. According to the cusp catastrophe theory, the discriminant of gravity dam instability criterion is obtained, and the stability of gravity dam is judged by calculating the conjugate condition set of extreme point and inflection point of standard potential function. Secondly, in the process of deep anti-slide stability analysis of gravity dam in Qingyu reservoir, The nonlinear finite element strength reduction method is used to obtain the displacement-strength reduction coefficient curve of each typical point in horizontal direction. When the displacement abrupt change of typical point is used as the criterion of instability, the safety factor obtained from different typical points is not unique. In this paper, the nonlinear finite element analysis of deep anti-slip stability of gravity dam in Qingyu Reservoir is carried out. According to the calculation results, the instability criterion of relative displacement cusp catastrophe model of gravity dam deep anti-slide stability is adopted. The safety factor obtained at this time is the same as that obtained by using the commonly used plastic zone through instability criterion. Finally, the double inclined plane method and the three oblique plane method are used to calculate the safety factor. The calculated results obtained by using the instability criterion of the cusp catastrophe model of relative displacement are compared with those of the double inclined plane method and the three oblique plane method. The relative error of the calculated results is relatively small. It is proved that the instability criterion of the cusp model of relative displacement of gravity dam is correct and applicable in engineering. In this paper, the cusp catastrophe model of the relative displacement-strength reduction coefficient of the upper and lower two points of the dam toe intercalation is established and used as the criterion of instability, which can reflect the catastrophe of the instability process of gravity dam. The safety factor can be quantified to an objective and concrete value, and the result is unique. By establishing the standard potential function of the model and comparing the size relation between the discriminant and the zero, the concept is clear. Clearly defined.
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV642.3;TV223

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