佛寺水库坝体渗流与坝坡稳定分析

发布时间：2018-04-24 21:07

本文选题：土石坝 + 渗流反演　；参考：《大连理工大学》2014年硕士论文

【摘要】：我国水利事业发展较早,并且修建了大量的水利工程,土石坝因工程施工简便,结构简单,便于维护,造价便宜,适应性好等原因而被广泛采用。在土石坝的设计建造和安全评价分析过程中,渗流分析和边坡稳定性分析都是最主要的考虑因素。通过土石坝的渗流分析和边坡稳定性分析之后,才能准确判断可能出现的隐患或病险并采取应对措施,或者对已出现的问题及时采取处理和加固措施,以保证大坝安全运行。本论文结合佛寺水库工程概况,应用GeoStudio软件对佛寺水库大坝进行坝体渗流和坝坡稳定分析,并评价工程安全性。佛寺水库建造时间较早,坝体材料、大坝结构等会随时间推移而产生变化,大坝可能出现异常渗流、坝坡不稳等严重问题,为了判定大坝安全性而进行坝体渗流和坝坡稳定的有限元分析之前,要先通过渗流反演分析推求坝体材料参数,本文采用的反演方法是BP神经网络法和试错法。首先建立三层结构的BP神经网络,然后通过有限元模型的计算分析选取大量训练样本对BP网络进行训练,得到合适的3-7-3型的网络结构,之后再利用控制变量的方法分析出粘土心墙和上下游壤土渗透系数的变化对测压管水头的影响,根据渗透系数和测压管水头的关系,最后联合试错法对大坝进行渗流反演分析,推得大坝0+510.1断面粘土心墙、上游壤土、下游壤土的渗透系数分别为5.90×10-06cm/s,1.00×10-05cm/s、2.00×10-04cm/s。反演求得坝体材料的渗流参数后,就可利用SEEP/W软件进行不同工况下的坝体渗流有限元分析,渗流分析结果表明0+510.1断面上,上游壤土与心墙联合防渗,坝基砂砾石覆盖层排渗效果较好,但仍有部分水头等值线分布在坝基风化岩当中；高水位工况下心墙下部的水平渗透坡降,可能导致心墙发生渗透破坏；各控制工况下该断面的单宽渗流量在0.257-0.855m3/d之间,且随水位的降低而减小。坝体渗流分析后,将SEEP/W软件的数据直接应用于SLOPE/W软件中,就可进行不同工况下的坝坡稳定性有限元分析,结果表明0+510.1断面坝坡稳定基本满足规范要求,但由设计洪水位快速降落至溢洪道堰顶高程的工况稳定安全系数不满足规范要求,会出现坝坡失稳现象。综上所述,可判断出大坝0+510.1断面坝体渗流稳定性基本满足规范要求,但还存有一定问题,建议对坝基未灌浆区域进行帷幕灌浆,以改善坝基渗流条件,保证坝基渗流稳定；对高渗透坡降区域进行防渗加固处理；对上游坝坡采取排渗加固措施,防止高水位情况下水位骤降引起的坝坡失稳。
[Abstract]:The development of water conservancy in our country is early and a large number of water conservancy projects have been built. The earth-rock dam is widely used because of its simple construction, simple structure, convenient maintenance, cheap cost and good adaptability. Seepage analysis and slope stability analysis are the most important factors in the design and construction of earth-rock dams and safety evaluation and analysis. Only after the seepage analysis and slope stability analysis of earth-rock dam can we accurately judge the hidden danger or disease risk and take countermeasures, or take timely treatment and reinforcement measures to ensure the safe operation of the dam. In this paper, combined with the general situation of Fosi reservoir project, GeoStudio software is used to analyze the seepage and slope stability of the dam, and the safety of the dam is evaluated. The Fossi reservoir was built earlier, the dam body material and dam structure will change with the passage of time, the dam may have serious problems such as abnormal seepage, unstable dam slope, etc. In order to determine the safety of the dam, before the finite element analysis of seepage flow and slope stability of the dam is carried out, the material parameters of the dam must be derived through the seepage inversion analysis. The inversion methods used in this paper are BP neural network method and trial and error method. Firstly, a three-layer BP neural network is established, and then a large number of training samples are selected to train the BP neural network through the finite element analysis, and a suitable 3-7-3 network structure is obtained. Then the influence of the change of permeability coefficient of clay core wall and upstream and downstream loam on the pressure pipe head is analyzed by using the method of controlling variables. According to the relation between the permeability coefficient and the water head of the pressure measuring pipe, the seepage inversion analysis of the dam is carried out by combined trial and error method. The permeability coefficients of clay core wall, upper loam and downstream loam are 5.90 脳 10 ~ (-6) cm / s ~ 1.00 脳 10 ~ (-5) cm / s ~ (2) 脳 10 ~ (-4) cm / s respectively. After obtaining seepage parameters of dam body material, finite element analysis of seepage flow of dam body under different working conditions can be carried out by using SEEP/W software. The seepage analysis results show that the upstream loam soil and core wall are combined to prevent seepage on section 0 510.1. The effect of sand gravel overburden on dam foundation is good, but there are still some water head isolines distributed in the weathered rock of dam foundation, the horizontal seepage slope of the lower part of the core wall under high water level condition may lead to the percolation failure of the core wall. The single wide seepage discharge of this section is between 0.257-0.855m3/d and decreases with the decrease of water level. After the seepage analysis of dam body, the data of SEEP/W software can be directly applied to SLOPE/W software, and the stability of dam slope under different working conditions can be analyzed by finite element method. The results show that the stability of 0 510.1 section dam slope basically meets the requirements of the code. However, when the design flood level drops rapidly to the top of the spillway Weir, the stability safety factor of the working condition does not meet the requirements of the code, and the instability of the dam slope will occur. In summary, it can be concluded that the seepage stability of the dam 0 510.1 section dam body basically meets the requirements of the code, but there are still some problems. It is suggested that curtain grouting should be carried out in the ungrouting area of the dam foundation in order to improve the seepage condition of the dam foundation and ensure the seepage stability of the dam foundation. In order to prevent the instability of dam slope caused by sudden drop of water level in high water level, seepage prevention and reinforcement measures are taken for upstream dam slope.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV641;TV223

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