【作者】 魏月娟；

【导师】 孙华东；

【作者基本信息】 中北大学 ， 工程力学， 2010， 硕士

【摘要】 边坡是自然界的地质体,是人类生产生活的最普遍的地理环境,与人们的各种活动密切相关,它的稳定性受多种因素的影响制约,譬如地层特性、地形地貌、地质构造、地下水、地震作用、人为活动等。因此,边坡的稳定性表现出动态的、非确定性的基本特性,其稳定性分析一直是岩土工程领域重要的研究课题,在工程实践中占据相当重要的地位。黄土地区边坡问题尤为突出,该地区由于受干旱半干旱气候的影响,黄土边坡基本属于非饱和土质边坡。基质吸力在控制非饱和土体力学性质方面起着十分重要的作用,在降雨入渗情况下,雨水的入渗使得边坡顶部非饱和区缩小,出现局部暂态饱和区,导致边坡土体基质吸力下降,抗剪强度减小,从而导致边坡稳定性的下降,因此,降雨入渗是导致边坡失稳的主要因素,是本文的研究重点。由于边坡稳定性分析方法很多,不同的方法又各具特点,有一定的适用条件。如何根据具体的边坡工程地质条件,具体的分析目的与精度要求,合理有效地选用与之相适应的边坡稳定性分析方法,是一项很重要的工作。目前边坡稳定性分析方法主要分为两大类：确定性分析方法和不确定性分析方法。本文主要考虑降雨入渗影响下的非饱和黄土边坡稳定性分析方法,运用非饱和土水分子运动方程,求解降雨入渗条件下边坡土体的吸水率,又考虑到其与非饱和土抗剪强度的关系,首先利用确定性分析方法中最具代表性的极限平衡法对非饱和黄土边坡稳定性进行了评价；由于边坡工程是一个复杂的开放系统,影响因素较多,并且带有相当的随机性、模糊性和不确定性,沿用传统的力学方法进行计算分析,存在许多问题和不足,因此,本文还针对相同条件下的黄土边坡稳定性用人工神经网络方法进行评价,并对两种方法的评价结果进行比较分析。更多还原

【Abstract】 Slope, the geological body of the nature,is the most common geographical environment of human production and life, and closely related to the various activities of human beings. Because its stability is affected by many factors constraining, such as strata characteristics, topography, geological structure, groundwater, earthquake, human activities,etc.,the performance of slope stability turns out dynamic, non-deterministic.So its stability analysis of geotechnical engineering has been an important research topic, occupying an important position in engineering practice.Loess slope is particularly prominent in the region. Due to the arid and semi-arid climate, loess slope essentially is classified into unsaturated soil slope.With regard to controlling physical properties of unsaturated soil, matricsuction plays an important role.In the case of rainfall infiltration,water infiltration so narrows unsaturated zone at the top of slope, and local temporary saturated zone presents, leading to decreased matricsuction of slope soil body, and weak shear strength, thus a decline in slope stability. It can be concluded that rainfall infiltration is the main factor contributing to slope instability, which is the focus of this study.There are many different ways to analyze the slope stability, and their characteristics differ under certain conditions of application. So it is believed to be exceptionally important to adopt reasonable and effective methods suitable to give one appropriate analysis on slop stability according to engineering geological conditions, the specific purpose of analysis and accuracy. Slope-stability-analysis methods currently fell into two categories:certain analysis and uncertain analysis.This paper is to employ slope stability analysis on unsaturated soil under the influence of rainfall infiltration, introducing motion equation of water molecular from unsaturated soil for the solution to moisture content in slope soil under the rainfall infiltration, but also taking into account the relationship between it and shear strength of non-saturated soil.So this paper firstly adopted the limit equilibrium method, the most typical one of the certainty analysis to value non-saturated loess slope stability;Since engineering is a complex open system, influenced by many factors and with considerable random, fuzzy and uncertainty, the traditional mechanical method of calculation had many problems and shortcomings,therefore, this article is devoted to providing an evaluation on loess slope stability with artificial neural network in response to the same conditions,and evaluation results of the two methods were compared.更多还原