【作者】 富强；

【导师】 冉启华；

【作者基本信息】 浙江大学 ， 水文学及水资源工程， 2010， 硕士

【摘要】 在水利工程中,水对工程设施的破坏是影响工程安全最主要的方面。其中尤以地下水对水利工程的作用不易观察,而且一经发现就难以挽回,常常引起严重的经济损失。因此水利工程对地下水渗流破坏的预防非常关键。土石坝作为世界坝工建筑中应用最广泛,发展最快的一种形式,结构简单,取材方便。这样的结构形式和材料特性,使得土石坝成为在各种形式的挡水建筑物中,与渗流关系最为密切的一种。渗流问题直接关系到土石坝工程的费用和安全,国内外许多溃决或破坏的土石坝工程,都是由渗流引发的。合理的渗流控制是保障土石坝安全运行的必要条件。本文选取土石坝中的粘土心墙坝作为典型研究对象,以辽宁柴河大坝为模板,建立了适于研究的三维数值模型。从土石坝渗流的机理出发,应用基于物理概念的先进水文数值模型InHM模型,通过对复杂条件下土石坝的渗流过程的模拟,得到不同状态工况下各时刻土石坝系统的浸润线位置、压强水头场、渗流量、流速场等要素并进行深入分析,从而探求土石坝渗流破坏的特性。本研究将土石坝渗流分为两类进行分析:包括稳定水位时不同作用水头、不同心墙、不同排水的情况,以及水位以不同方式变化时土石坝渗流的情况。重点针对水位变化条件下,土石坝内部渗流场的改变特性以及渗流危险位置和危险时间的发生做了考察。通过一系列针对性的研究,得出以下结论:1.水头差是土石坝渗流的驱动因素;2.大坝全局最危险的部位在坝趾出流处和心墙下游侧;3.心墙对渗流的作用与其厚度有关;4.排水体在土石坝渗流控制中有着两方面的综合作用;5.水位变化情况下,土石坝渗流危险区域和危险时间根据水位变化方式有所不同。更多还原

【Abstract】 Hydraulic factors are always important in embankment engineering. Seepage is one of the most dangerous because it is difficult to monitor. As one of the most popular dam types, earth dam is very sensitive to seepage. It is extremely important for extra attention to be paid to this problem since most of the earth dam failures were caused by seepage.In this dissertation, the seepage processes of earth dams under complex conditions were simulated by using a physics-based hydrological model: Integrated Hydrology Model (InHM). Phreatic surface, seepage discharge, and seepage velocity were analyzed to study the characteristics and mechanism of earth dam seepage.Both the steady-state seepage and the transient seepage were simulated and analyzed in this dissertation. The simulation scenarios considered different steady water head, various thickness of the clay core, with/without drainage structure, and the rising/declining of the water level. The seepage in upslope under drawdown condition was investigated in detail since it is the most dangerous condition.Following conclusions were generated by this study:1. The water head is the driving force for the seepage in earth dams;2. Related to seepage, the most dangerous locations include 1) the seepage face near the dam toe and 2) in the dam, around the downstream side of clay core;3. The efficiency of the clay core is related to its thickness: not necessarily the thinner the better4. The drainage structure has both positive and negative effects in seepage control;5. The transient seepage caused by changing water level is extremely complex and need to be handled carefully.更多还原