【作者】 何刚；

【导师】 陈建康；

【作者基本信息】 四川大学 ， 水工结构工程， 2003， 硕士

【摘要】 目前，我国已建各类水库87000余座，大坝坝型以土石坝为主，约占90％以上。这些水库绝大多数为五十～七十年代建造(约80000座)，为我国水利水电建设奠定了坚实的基础，对我国国民经济建设发挥了重要作用。但此间建造的大坝，已经运行了三、四十年，有的将近半个世纪，即使是优质工程，也难免有老化问题。我国是世界上拥有水库大坝座数最多的国家之一，而溃坝率亦位居世界前列，因此，在注重其巨大社会与经济效益的同时，如何正视水库枢纽之关键性建筑物——大坝的风险问题，如何在新工程的立项决策和已建工程的安全评估中全面系统地考虑各种因素的变异特征，科学合理地把握每座大坝的风险程度，是一个急待研究的课题。 在进行大洪河水土坝风险分析之前，本文首先对其40余年的变形与渗流长系列监测资料进行了统计分析，在深入分析研究大坝变形与渗流变化规律的同时，构建了大坝变形与坝体渗流规律模拟模型，探讨了各环境因子对大坝变形与渗流的影响程度，以期对大坝工作性态作出科学、合理的评价。 众所周知，我国拥有的土石坝数量居世界第一，而其失事率亦居榜首，可以说大坝风险，土石坝尤为突出。本文在查阅国内外大量文献资料的基础上，针对土石坝工程特点，通过对其失事模式的分析，应用工程风险及可靠度分析理论，建立了土坝坝坡、渗流破坏及超标洪水漫顶失事的风险模型，采用Monte-Carlo法对大洪河土坝坝坡、渗流风险分析以及皮尔逊Ⅲ型曲线拟合大洪河历史和运行期洪水资料推求超标洪水漫顶风险分析证明了模型的合理性，并四川大学硕士学位论文采用宽窄界限法对该工程大坝整体风险进行了评估。据笔者所查，对土坝三项风险建模分析尚未见相关报道。 大洪河土坝监测资料分析表明，坝体垂直与水平变形呈现出总量逐年增大，而增量逐年减小的趋势，坝体变位曲线已趋收敛，大坝变形稳定。大坝测压管水位变化趋势反映出坝体空隙水压强已明显减弱，渐趋稳定，并由施工期及运行初期反映空隙水压强为主转变为以反映坝体渗流浸润面为主的阶段，大坝渗流工作性态正常。在影响坝体变形、渗流的诸多环境因子中，以时效因子影响最大，库水位次之，符合土坝的一般规律。 采用本文所构建的风险模型对大洪河土坝三项风险分析表明，坝坡失稳、渗透破坏及漫顶失事的风险率分别为4.305x10-’，9.080xl。，及2.246x10一，，根据宽窄界限估计法，该大坝的整体风险率为2.335、1『，‘乃‘2.377 x 10一参考混凝土坝有关规范规定及该工程实际运行情况，认为该大坝运行是安全可靠的。 我国水利水电工程风险分析尚属起步阶段，本文所做研究工作是在土坝风险建模及分析方法方面的一次探索和新的尝试。针对不同失事模式构建的风险分析数学模型可供类似工程借鉴，亦可推广采用于土石坝工程设计与安全评价的风险决策分析。更多还原

【Abstract】 At present, there have been about 87,000 reservoirs in China, among which above 90% or so are earth dams. Most of them were built in the 1950s- 1970s(about eighty thousands), which have established firm base for water conservancy construction and took great effect for national economic development. However, the dams built during the period have worked for over thirty or forty years, some even for nearly half century, some dams has aged, including some high quality engineering. China is one of the countries which have the most amount of dams in the world and the ratio of dams failure is front-line in the world, too. Therefore, howto dispose correctly the key structure of the reservoir conservancy project-therisk questions of dams, how to consider fully and systemically all kinds of the variable characteristics in decision-making of the new engineering in safety assessment of the engineering built, and how to grasp the risk degree of each dam scientifically and reasonably is an urgent subject.Before the risk analysis of the Da Hong River earth dam, in this paper, a long series of displacement and seepage for over forty years is analysed statistically, while analysing the disciplinarians of displacement and seepage of the dam, the simulation models of displacement and seepage of the dam are established and theinfluence degree to displacement and seepage are explored by each environmentalfactor in order to make the scientific and reasonable assessment.It is well known that China is the country, which has the most amount of the earth dam throughout the world, and the same to the cases of accidents, among them, the earth dam safety is especially serious. Aiming at the characteristics of the earth dam, through the analysis of their failure modes, the risk model of earth dam failure caused by landslide, seepage and over-standard flood overtopping is founded according to the overseas and domestic statistical data. Its rationality is proved through the risk ratio analysis with the applying the Monte-Carlo method to the landslide failure -, seepage failure and flood over-standard overtopping and through P-D curve by fitting of historical and the operation period flood data of the Da Hong River and the whole risk analysis of the dam has been assessed by the width limit method. According to the existing reference, it is the first application of the risk model analysis of three items.It can be seen from the observational data analysis results of the Da Hong River earth dam that the total amount of the vertical and horizontal displacement has a trend of the stepwise increase year after year, while the increment is minishing. The displacement curve of the dam body has converged, and displacement of the dam is stable. Pore water pressure intensity loweres obviously and is coming to be steady. The water level in piezometric pipes has changed from mainly reflecting water pressure intensity during the construction and operation period to mainly reflecting seepage wetted area now. Among the factors influencing displacement and seepage of the dam, the time factor takes the greatest effect, and the reservoir water level is in succession, it answers for the general rules of the earth dam.Three items risk analysis of the Da Hong River earth dam hi the application of the risk models built hi this paper indicate that the risk ratio of landslide failure, seepage failure and flood overtopping is respectively 4.305 ×10-4,9.080×10-4 and2.246×10~2. According to the width limit method, the whole risk ratio of the dam is 2.335×10-2 <Pf < 2.377 ×10~2. In the reference of the criterions of the concretedam and the practical operation situation of the dam, it can been drawn a conclusion that this dam works safely and reliably.The engineering risk analysis of the hydro projiect in China is in the stage of the beginning. The study in this paper is an explore and a new attempt to the risk analysis of the earth dam. The risk analysis model aiming to the different failure modes is able to be referenced by更多还原