基于模糊数学的降雨条件下边坡渗流特性及稳定性分析

发布时间：2018-05-18 08:50

本文选题：道路工程 + 模糊数学　；参考：《长沙理工大学》2015年硕士论文

【摘要】：广西位于我国南部地区,全年湿润多雨;加之近几年我国经济的不断发展,人类活动逐渐增加,在一定程度上破坏了地质环境,最终提高了发生地质灾害的可能性,给人民的生命财产造成了巨大损失。因此,根据广西气象及地形特点,寻找符合实际情况的降雨因子,并判断边坡稳定性显得尤为重要。本文将针对降雨因子进行模糊综合评价,通过对降雨入渗模型中的降雨因子用模糊数学的方法进行优化选择,进一步提高了目标函数值,从而使得到的结果更加符合实际情况。通过运用Geostudio软件分析降雨条件下边坡稳定性,能够较为准确地评价出边坡失稳概率,同时,为人工防治边坡出现失稳破坏现象提供了一定的可靠依据。由此可见,此次研究具有非常重要的理论意义和工程应用价值。本文取得的主要研究成果如下:(1)在优化选取降雨因子过程中。以降雨强度、降雨历时及降雨雨型作为对象集,并以最小边坡安全系数、边坡失效概率、最早达到饱和时间点和暂态饱和区面积作为评价指标;利用SAS8.1统计分析软件回归拟合模糊综合评价值,得到合适的降雨因子。(2)降雨入渗边坡过程中,随着降雨的持续,不只是位于边坡表面的土体孔隙水压力升至正值,距坡面一定深度范围内孔隙水压力均得以提高,且地下水位线以下的孔隙水压力值一直大于0。此外,本章还在坡脚处选取一特征截面,以便分析距坡面不同位置处的孔隙水压力变化,认为孔隙水压力距坡面越远而越小,且在该层降雨入渗深度为6.5米。(3)随着降雨强度的增大,安全系数迅速降低,且变化幅度也有所增大;不同降雨历时下的边坡安全系数随降雨历时的增大而降低,待雨停后,安全系数不会立刻降低,而是呈现先上升后下降的趋势;不同降雨雨型对边坡稳定性产生的影响各不相同,本文计算方案中,间断性降雨与连续型降雨相比,边坡更易发生失稳破坏。
[Abstract]:Guangxi is located in the southern part of China. It is wet and rainy throughout the year. In addition, with the continuous development of our economy in recent years, human activities have gradually increased, which to a certain extent has damaged the geological environment and finally raised the possibility of geological disasters. Great losses have been caused to the lives and property of the people. Therefore, it is very important to find rainfall factors and judge slope stability according to the characteristics of Guangxi meteorology and topography. In this paper, the fuzzy comprehensive evaluation of rainfall factors is carried out, and the optimal selection of rainfall factors in rainfall infiltration model is carried out by means of fuzzy mathematics, which further improves the value of the objective function and makes the results more in line with the actual situation. By using Geostudio software to analyze slope stability under rainfall conditions, the probability of slope instability can be evaluated more accurately, and it provides a reliable basis for artificial prevention and control of slope instability. Thus, this study has very important theoretical significance and engineering application value. The main research results obtained in this paper are as follows: 1) in the process of optimizing the selection of rainfall factors. Taking rainfall intensity, rainfall duration and rainfall pattern as object set, and taking minimum slope safety factor, slope failure probability, saturation time point and transient saturation area as evaluation index; By using the SAS8.1 statistical analysis software to regress and fit the fuzzy comprehensive evaluation value, the suitable rainfall factor. 2) in the process of rainfall infiltration, with the continuous rainfall, the pore water pressure of soil is not only rising to positive value on the slope surface. The pore water pressure can be increased in the range of certain depth from the slope, and the pore water pressure below the underground water level line is always greater than 0. In addition, this chapter selects a characteristic section at the foot of the slope in order to analyze the variation of pore water pressure at different locations from the slope surface. It is concluded that the farther away the pore water pressure is from the slope surface, the smaller the pore water pressure is. With the increase of rainfall intensity, the safety factor of slope decreases rapidly and the range of variation increases, and the slope safety coefficient decreases with the increase of rainfall duration, and the slope safety coefficient decreases with the increase of rainfall duration. The factor of safety does not decrease immediately, but increases first and then decreases. The effects of different rainfall patterns on slope stability are different. In this calculation scheme, intermittent rainfall is compared with continuous rainfall. The slope is more vulnerable to instability and failure.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU43

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