基于有限元法的边坡稳定可靠度研究

发布时间：2018-02-16 11:07

本文关键词： 边坡稳定有限元安全系数四阶矩法神经网络截尾分布　出处：《湖南大学》2016年硕士论文　论文类型：学位论文

【摘要】：土体参数具有一定的变异性,在进行边坡稳定分析时采用基于概率的可靠度方法更加合理。目前,国内外边坡稳定可靠度分析的主要方法有一次二阶矩法、二次二阶矩法、响应面法、蒙特卡罗法等可靠度分析方法。其中,采用一次二阶矩法和二次二阶矩法的难点在于精确求解隐式功能函数偏导数,采用响应面法的难点在于响应面函数对取样点尤其是试验点附近需要很好的拟合,采用蒙特卡罗法时需要繁重的计算量。针对这些问题,本文研究了基于有限元法的边坡稳定可靠度分析方法。并根据截尾分布研究了土体参数左右截尾点对边坡稳定影响的敏感度。通过研究本文获得了如下研究成果。(1)根据边坡等效塑性应变的分布以及极限平衡理论,本文提出了一种确定边坡滑裂面以及安全系数的方法。该方法兼具了边坡稳定分析中有限元方法和极限平衡法的优点。本文将该方法计算结果与极限平衡法计算结果对比验证了该方法精度。同时本文也研究了根据刚刚贯通的塑性区确定边坡临界滑裂面的合理性;探讨了重力加速度取值对滑裂面位置及其边坡安全系数影响;探讨了滑裂面的离散数目对边坡安全系数的影响。(2)本文提出了一种边坡稳定可靠度分析的新型四阶矩计算方法。该方法将均匀设计法、径向基神经网络技术、最大熵原理相结合对边坡进行可靠性分析。最终得到边坡安全系数的概率密度函数近似表达式、边坡失效概率以及相应的可靠指标。本文将该方法的计算结果与蒙特卡罗法的计算结果对比验证了该方法的精度。(3)本文获得土体参数左右截尾点对边坡稳定影响的敏感性规律。采用本文提出的边坡稳定可靠度分析的四阶矩方法计算土体参数不同截尾点对应的边坡可靠指标,采用灰色关联理论对土体粘聚力和内摩擦角左右截尾点的敏感度进行了分析。该研究结果将会为基于截尾分布边坡稳定研究提供一些借鉴和参考。
[Abstract]:The reliability method based on probability is more reasonable in slope stability analysis. At present, the main methods of slope stability reliability analysis at home and abroad include first order second moment method, second order second order moment method, and second order second moment method. Among the reliability analysis methods such as response surface method and Monte Carlo method, the difficulty of using the first order second moment method and the second order second order moment method is to accurately solve the partial derivative of implicit function function. The difficulty of using the response surface method is that the response surface function needs to fit the sampling points, especially near the test points, and the Monte Carlo method requires heavy calculation. In this paper, the reliability analysis method of slope stability based on finite element method is studied, and the sensitivity of soil parameters to slope stability is studied according to the distribution of truncation. The following research results are obtained by studying the influence of soil parameters on slope stability. According to the distribution of equivalent plastic strain of slope and the theory of limit equilibrium, In this paper, a method for determining the slip surface and safety factor of slope is presented. The method has the advantages of finite element method and limit equilibrium method in slope stability analysis. The results verify the accuracy of the method, and the rationality of determining the critical slip surface of the slope according to the newly through plastic zone is also studied in this paper. The influence of gravity acceleration on the location of the slip surface and the safety factor of the slope is discussed. This paper discusses the influence of the discrete number of slip surfaces on the safety factor of slope. In this paper, a new method of calculating the stability reliability of slope is presented. The uniform design method and the radial basis function neural network technique are used to calculate the stability reliability of the slope. The maximum entropy principle is combined to analyze the slope reliability. Finally, the approximate expression of the probability density function of the slope safety factor is obtained. This paper compares the calculation results of this method with that of Monte Carlo method and verifies the accuracy of the method. 3) in this paper, the influence of soil parameters on slope stability is obtained. The fourth moment method of slope stability reliability analysis proposed in this paper is used to calculate the slope reliability index corresponding to different truncated points of soil parameters. Grey correlation theory is used to analyze the sensitivity of the soil cohesion and the left and right truncation points of the internal friction angle. The results will provide some reference for the study of slope stability based on the truncated distribution.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU43

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