【作者】 赵瑜；

【导师】 王铁成；

【作者基本信息】 天津大学 ， 结构工程， 2009， 博士

【摘要】 在大坝失事事故中,土石坝所占比例高达70.5%。渗流问题是土石坝中的常见问题,严重影响水库的安全运行。目前,对水库防渗加固效果的研究还比较少,因此,开展土石坝防渗加固和安全监测及评价研究就显得十分重要且意义重大。本文以某水库堤坝防渗加固工程为背景,主要通过模型试验、有限元计算及实测数据分析,论证了影响土石坝防渗加固效果的各种因素,对加固工程的防渗效果进行了系统研究,开发了渗流安全监测及评价系统。基于二维饱和-非饱和渗流的基本方程,应用伽辽金法对其进行了离散,得到有限元控制方程。针对某水库堤坝采用高压旋喷混凝土地下连续墙全封闭的加固情况,采用有限元软件SEEP/W分析了影响堤坝渗流的各种因素。结果表明,在已建水库堤坝的防渗加固工程中,防渗墙的施工质量对加固效果影响最大。进行了不同堤坝断面、不同渗透系数的防渗墙水库堤坝加固前后的模型渗透试验研究,并与数值计算做了对比验证。结果表明,堤坝加固后,渗流速度明显减小,渗流量相应下降幅度可达26.9%~71.6%;总水头和堤坝浸润线明显降低,渗透坡降普遍下降幅度可达29%~75%,抗渗能力明显提高。对实测测压管水位值的相关分析,也说明整体加固效果良好。有限元数值计算也能够很好地模拟防渗加固工程的渗流形态,其结果可以作为设计和施工的重要参考。通过振动模型试验,研究分析了各种工况下堤坝的抗液化能力。结果表明,当与堤坝接触的土层为粘土时,堤坝不易液化破坏;当接触土层为粉土或者沙土时,堤坝较易液化破坏。加固后堤坝在地震波作用下具有较好的抗液化性能。研究了某堤坝各渗流影响因子与等效可监测效应量的相关关系,建立了渗流监测模型,F和T检验表明相关性很好。基于ACCESS 2003数据库,利用VB6.0语言,开发了科学实用且智能化的堤坝渗流监测及多级模糊识别综合评价管理系统。可以有效地对水库堤坝性能起到监测、预测和安全评价作用。更多还原

【Abstract】 Among all the accidents of the dams, those of earth - rock dams made up the biggest share, accounting for 70.5 percent of the total. Seepage is a common problem of earth - rock dams and is harmful to the safety of the dam when the seepage is serious. At present, the research about the effects of the seepage reinforcement is limited, so it is essential to study the seepage reinforcing, safe monitoring and evaluating problems of the earth - rock dams.In this paper, based on model tests, calculation of the finite element and analysis of the prototype observed data of the anti-seepage reinforcement project of the reservoir dyke, each factor which affects seepage of the earth - rock dam is analyzed,impervious effect of the project is studied systematically. Safe monitoring and evaluating system on seepage is developed.Based on the 2-D saturated and unsaturated basic seepage equation, a FEM (Finite Element Method) governing equation for seepage problem is presented by applying Galerkin Method. Various factors which affect seepage are analyzed by using the FEM software SEEP/W to the earth - rock dam reinforced by the underground diaphragm wall. The results indicate that the construction quality of the wall is the most significant factor for impervious effect of the dyke.Through model tests of different cross-sections with different cutoff walls which have different permeability coefficients, comparison between the testing results and calculating results is made. The results indicate that the seepage velocity reduces obviously, seepage quantity declines 26.9～71.6 percent, the total water head as well as the saturation line decreases, and seepage gradient declines 29～75 percent after reinforced. The capacity of seepage resistance of the dyke has a remarkableimprovement. Through correlation analysis of the prototype observed data, overall reinforcing effect is verified to be better. From above, the numerical analysis can simulate the reinforcement project more perfectly, and the result calculated can be the reference of design and construction.According to the vibrating experiment of the model, the capacity of earthquake-induced liquefaction under many working conditions is analyzed. The experimental results indicate that when the dyke directly contacts clay it has stronger liquefaction resistance, and when the dyke directly contacts silt or sand soil it has weaker liquefaction resistance. The dyke shows liquefaction resistance better in the case of earthquake after reinforced.The relation between the factors which affect seepage of the dyke and the equivalent factors which can be directly measured is studied, and the seepage-monitoring model also be established. F and T inspections show that correlation is better. Based on ACCESS 2003 and VB6.0, the dyke seepagemonitoring and multi-fuzzy evaluating system which is a scientific practical andintellectual system is developed. It can play an effective role in monitoring, predicting and safe evaluating for behaviors of the dyke.更多还原