降雨条件下非饱和土边坡的渗流场分析

发布时间：2018-02-23 22:12

本文关键词： 非饱和土降雨边坡渗流　出处：《河北工业大学》2014年硕士论文　论文类型：学位论文

【摘要】：边坡广泛存在于我国的大部分地区，雨季边坡失稳崩塌现象屡见不鲜，因而降雨条件下的非饱和土边坡渗流分析是土力学与岩土工程学中的重点、经典课题。常规的边坡稳定性分析方法主要基于饱和土理论和稳定渗流场情况，难以反映实际情况下降雨作用对边坡的影响。本文首先介绍了关于边坡渗流问题的国内外研究现状，然后阐述了渗流基本理论、基本方程和非饱、土的基本概念和FLAC3D中的渗流分析，以此作为本文的理论基础。本文主要针对降雨条件下非饱和土边坡的渗流场问题，采用三维有限差分数值模拟软件FLAC3D对其进行数值模拟，具体的研究内容包括以下几点：在选择合适土层的基础上，建立坡度不同的三个模型。再根据降雨量、渗透系数、雨型和坡度分成不同的工况；借助FLAC3D分析相应的土层参数、初始状态，建立三维地面渗流模型，针对不同的工况进行数值模拟分析，，分别得到了不同工况下的边坡渗流场分布；通过模拟不同的工况，得出降雨强度、土体的渗透系数、雨型和边坡坡度对非饱和土边坡渗流场的影响。通过模拟十种不同工况下的边坡渗流场，得到以下结论： 1.降雨强度越大，边坡中孔隙水压力变化的程度越大。 2.土体的渗透系数越大，雨水的入渗速度越大，则入渗的深度越深。 3.当降雨有间歇时，随着雨水的消散，表层基质吸力增加，雨水在重力作用下向下运动，使得下部的基质吸力有所降低。当继续降雨时，表层和内部的基质吸力降低。 4.随着边坡坡度的不断增加，坡面上基质吸力降低的程度逐渐减小。 5.当降雨强度大于土体的渗透系数时容易形成地表径流，并积聚成水膜。水膜的存在对非饱和土边坡的孔隙水压力分布有着很大的影响。论文的研究成果对降雨条件下非饱和土边坡渗流的分析具有一定的指导意义。
[Abstract]:The slope exists widely in most areas of our country, and the unstable slope collapse phenomenon is common in the rainy season. Therefore, the seepage analysis of unsaturated soil slope under rainfall condition is the key point in soil mechanics and geotechnical engineering. The conventional method of slope stability analysis is mainly based on saturated soil theory and steady seepage field. It is difficult to reflect the effect of rainfall on slope in practice. This paper first introduces the research status of slope seepage problem at home and abroad, and then expounds the basic theory of seepage, basic equations and basic concepts of unsaturated soil and seepage analysis in FLAC3D, which is the theoretical basis of this paper. In this paper, the seepage field of unsaturated soil slope under rainfall condition is numerically simulated by using 3D finite difference numerical simulation software FLAC3D. The specific research contents are as follows: on the basis of selecting suitable soil layer, Three models of different slope are established. According to rainfall, permeability coefficient, rain type and slope, the model is divided into different working conditions. By means of FLAC3D, the corresponding soil parameters and initial state are analyzed, and a three-dimensional surface seepage model is established. According to the numerical simulation analysis of different working conditions, the seepage field distribution of slope under different working conditions is obtained, and the rainfall intensity and soil permeability coefficient are obtained by simulating different working conditions. Effects of rain type and slope gradient on seepage field of unsaturated soil slope. By simulating the seepage field of the slope under ten different working conditions, the following conclusions are obtained:. 1. The greater the rainfall intensity, the greater the change of pore water pressure in the slope. 2. The greater the permeability coefficient of soil, the deeper the infiltration depth of Rain Water. 3.When the rainfall is intermittent, with the dispersing of Rain Water, the suction of the surface matrix increases, and Rain Water moves downward under the action of gravity, which makes the suction of the lower part of the matrix decrease, and when the rainfall continues, the suction of the surface and the inner matrix decreases. 4. With the increasing of slope, the decrease of matrix suction on slope gradually decreases. 5. When rainfall intensity is greater than the permeability coefficient of soil, surface runoff is easy to form and water film is accumulated. The existence of water film has great influence on pore water pressure distribution of unsaturated soil slope. The research results of this paper have certain guiding significance for the analysis of unsaturated soil slope seepage under rainfall conditions.
【学位授予单位】：河北工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU43

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