降雨入渗条件下土坝渗流和稳定性影响分析
发布时间：2019-03-19 07:02
【摘要】：降雨入渗是导致土石坝失稳的主要诱发因素，它会影响到坝体孔隙水压力分布，很多坝体滑坡都与降雨有着直接而紧密的联系。由于近年来降雨引发的边坡失稳越来越频繁，因此，分析研究降雨入渗对边坡稳定性影响及预测滑坡发生的可能性，在工程应用上具有非常重要的意义。本文在研究降雨入渗对土石坝坡渗流与稳定的影响时，运用饱和-非饱和渗流理论和坝坡稳定分析理论，并利用有限元软件模拟分析不同降雨条件下雨水入渗对坝坡渗流场及稳定性的影响。研究的主要内容有： (1)阐述饱和—非饱和渗流问题的基本理论，从渗流的物理方程出发推导出饱和—非饱和渗流基本微分方程。在饱和渗流控制方程基础上推导出饱和一非饱和渗流控制方程，给出了降雨条件下的边界条件，并给出其定解条件。 (2)介绍有关降雨入渗的几个常见模式，对雨水在土质边坡的入渗过程进行分析研究。为了更好地理解降雨入渗数值模拟过程并得出正确的分析结果，针对数值模拟具体实施过程中需要注意到的关键问题进行了探讨，如降雨入渗初始边界条件的设置、土—水特征曲线的定义及渗透性系数函数的定义。 (3)叙述降雨入渗条件下土坡稳定分析理论，介绍几种常用的土坡稳定分析方法，如极限平衡法、圆弧条分法。在土坡稳定分析中把降雨入渗作为重要的影响因素，分析降雨入渗对坝坡稳定影响机理。 (4)引用江西省鄱阳县滨田水库工程实例，利用简单的二维土坝坝坡模型对不同降雨条件下坝体渗流和稳定进行分析，计算出不同降雨强度、降雨历时、雨型和前期降雨等条件下的渗流场，并根据计算出来的渗流结果进行了土坡稳定分析，，得到相应情况下坝坡稳定安全系数变化规律，研究坝坡稳定安全系数对降雨强度、降雨持续时间、雨型及前期降雨的敏感程度。 本论文的研究工作主要在于试图改进和完善土质边坡渗流与稳定数值计算方法，对降雨诱发的边坡失稳机理和规律有进一步的认识。可为今后水库除险加固提供参考依据，也能为在雨季水库坝坡滑坡预测和坝坡的设计提供科学依据。
[Abstract]:Rainfall infiltration is the main cause of instability of earth-rock dam, it will affect the distribution of pore water pressure in dam body, and many dam landslides are directly and closely related to rainfall. Because the slope instability caused by rainfall is more and more frequent in recent years, it is very important to analyze and study the influence of rainfall infiltration on slope stability and predict the possibility of landslide occurrence. In this paper, when studying the influence of rainfall infiltration on seepage flow and stability of earth-rock dam slope, the saturated-unsaturated seepage theory and the stability analysis theory of dam slope are applied. The influence of Rain Water infiltration on seepage field and stability of dam slope under different rainfall conditions is simulated by finite element software. The main contents of the study are as follows: (1) the basic theory of saturated-unsaturated seepage is expounded, and the basic differential equation of saturated-unsaturated seepage is derived from the physical equation of seepage. Based on the governing equation of saturated seepage, the governing equation of saturated-unsaturated seepage is derived, the boundary conditions under rainfall are given, and the definite solution conditions are given. (2) several common models about rainfall infiltration are introduced, and the infiltration process of Rain Water in soil slope is analyzed and studied. In order to better understand the numerical simulation process of rainfall infiltration and obtain the correct analysis results, the key problems that need to be paid attention to during the concrete implementation of the numerical simulation are discussed, such as the setting of the initial boundary conditions of rainfall infiltration. The definition of soil-water characteristic curve and the definition of permeability coefficient function. (3) the theory of slope stability analysis under rainfall infiltration is described, and several commonly used methods of slope stability analysis, such as limit equilibrium method and circular arc slice method, are introduced. In the stability analysis of soil slope, rainfall infiltration is regarded as an important influence factor, and the influence mechanism of rainfall infiltration on dam slope stability is analyzed. (4) citing the example of Bintian Reservoir Project in Poyang County, Jiangxi Province, using a simple two-dimensional earth dam slope model, the seepage flow and stability of dam body under different rainfall conditions are analyzed, and the different rainfall intensity and rainfall duration are calculated. According to the calculated seepage results, the stability analysis of soil slope is carried out, and the variation rule of stability safety factor of dam slope under the corresponding conditions is obtained, and the effect of stability safety factor of dam slope on rainfall intensity is studied, and the influence of stability safety factor of dam slope on rainfall intensity is studied. Rainfall duration, rainfall type and the sensitivity of previous rainfall. The main research work of this paper is to improve and perfect the numerical calculation method of seepage flow and stability of soil slope, and to further understand the mechanism and law of slope instability induced by rainfall. It can be used as a reference for reservoir reinforcement in the future as well as a scientific basis for landslide prediction and design of dam slope in rainy season.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV223.4
本文编号：2443290
[Abstract]:Rainfall infiltration is the main cause of instability of earth-rock dam, it will affect the distribution of pore water pressure in dam body, and many dam landslides are directly and closely related to rainfall. Because the slope instability caused by rainfall is more and more frequent in recent years, it is very important to analyze and study the influence of rainfall infiltration on slope stability and predict the possibility of landslide occurrence. In this paper, when studying the influence of rainfall infiltration on seepage flow and stability of earth-rock dam slope, the saturated-unsaturated seepage theory and the stability analysis theory of dam slope are applied. The influence of Rain Water infiltration on seepage field and stability of dam slope under different rainfall conditions is simulated by finite element software. The main contents of the study are as follows: (1) the basic theory of saturated-unsaturated seepage is expounded, and the basic differential equation of saturated-unsaturated seepage is derived from the physical equation of seepage. Based on the governing equation of saturated seepage, the governing equation of saturated-unsaturated seepage is derived, the boundary conditions under rainfall are given, and the definite solution conditions are given. (2) several common models about rainfall infiltration are introduced, and the infiltration process of Rain Water in soil slope is analyzed and studied. In order to better understand the numerical simulation process of rainfall infiltration and obtain the correct analysis results, the key problems that need to be paid attention to during the concrete implementation of the numerical simulation are discussed, such as the setting of the initial boundary conditions of rainfall infiltration. The definition of soil-water characteristic curve and the definition of permeability coefficient function. (3) the theory of slope stability analysis under rainfall infiltration is described, and several commonly used methods of slope stability analysis, such as limit equilibrium method and circular arc slice method, are introduced. In the stability analysis of soil slope, rainfall infiltration is regarded as an important influence factor, and the influence mechanism of rainfall infiltration on dam slope stability is analyzed. (4) citing the example of Bintian Reservoir Project in Poyang County, Jiangxi Province, using a simple two-dimensional earth dam slope model, the seepage flow and stability of dam body under different rainfall conditions are analyzed, and the different rainfall intensity and rainfall duration are calculated. According to the calculated seepage results, the stability analysis of soil slope is carried out, and the variation rule of stability safety factor of dam slope under the corresponding conditions is obtained, and the effect of stability safety factor of dam slope on rainfall intensity is studied, and the influence of stability safety factor of dam slope on rainfall intensity is studied. Rainfall duration, rainfall type and the sensitivity of previous rainfall. The main research work of this paper is to improve and perfect the numerical calculation method of seepage flow and stability of soil slope, and to further understand the mechanism and law of slope instability induced by rainfall. It can be used as a reference for reservoir reinforcement in the future as well as a scientific basis for landslide prediction and design of dam slope in rainy season.
【学位授予单位】：南昌大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV223.4
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