【作者】 李雷；

【导师】 王恩志； 路新景；

【作者基本信息】 清华大学 ， 水利工程， 2005， 硕士

【摘要】 西霞院工程作为黄河小浪底水利枢纽的配套工程,其任务是以对小浪底电站泄流进行反调节为主,充分发挥小浪底枢纽所承担的供水、灌溉和发电等综合利用效益。西霞院水库坝型为土石坝,建在砂砾石地基上,其渗透稳定是该工程设计中的关键问题之一。在设计过程中,渗流及渗透稳定计算极其重要,而对坝体渗流稳定计算来说,最关键最重要的是坝体材料渗透特性参数的正确选择。针对坝体和坝基渗透稳定问题,开展了坝体材料的物理特性、渗透特性、允许比降和有限元渗流计算方面的研究,取得了有实用性的成果和深入的认识,为工程设计和施工提供了必要的分析成果和参考依据。主要的成果如下:应用三次样条的概念和性质,绘制坝体材料的颗粒级配曲线,并利用样条函数计算砂砾石的特征粒径和不均匀系数。采用Mann-Whitney U检验方法,对白坡料场和堡子料场的颗粒组成性质进行统计分析,结果显示它们属于同一总体。还建立了颗粒级配与孔隙率的相关关系。根据渗流试验资料,建立了渗透系数与控制粒径、砾石含量、孔隙率函数三者的关系。采用单样本K-S检验法,推断出渗透系数取对数后服从正态分布。利用多项式拟合的方法,得到了渗透系数的概率密度函数。根据渗透变形试验资料,研究分析了筑坝材料发生渗透变形的临界水力比降和坝基发生渗透变形的临界比降,进一步提出了坝体、坝基的允许水力比降,并以此作为判断是否产生渗透破坏的标准。根据渗流的基本理论和西霞院土石坝的结构与坝基的地质条件,采用连续介质渗流分析方法,建立了西霞院大坝的渗流分析模型。在西霞院河漫滩和河床坝段各取一个典型断面,利用有限元数值计算原理进行渗流计算,得到了多种工况下的渗流特征,分析了水力比降的分布和变化特征。根据不同防渗状况下的分析结果,推荐了合理的防渗方案。根据渗流分析,提出了两项建议。一是,根据有、无反滤层的不同计算结果,建议在下游坝体坡脚处设置反滤层。二是,根据土工膜局部失效时坝体的渗流特征,建议土工膜在运输、铺设过程中,要采取保护措施;在土工膜的热焊或胶粘接缝处理时,要控制质量。更多还原

【Abstract】 XIXIAYUAN project pertains to the project in Xiao Langdi waterconservancy hinge of the Yellow River, its task is to accommodate mainly thehydropower station of Xiao Langdi, to exert fully its synthetical benefit aswater supply , irrigate and generate electricity etc. XIXIAYUAN reservoirdam type is earth dam , Built on gravel stone ground , Its permeated stabilityis one of the key problems in this engineering design . In the course ofdesigning, the seepage calculation is important extremely. To steadycalculation of the dam, The most important thing is the correct choice of theseepage characteristic parameter . contraposing the seepage question of thedam body and dam foundation , Launch the research that including thephysical characteristic of dam material , seepage characteristic , allowablehydraulic grads and finite element seepage calculate ect. Have obtained theachievement with practicability and deep understanding, afforded the essentialanalysis achievement and the referential gist to engineering design. The mainachievement is as follows:Useing the concept and character of spline fit approximation, drew thecurve of the dam material particle magnitude, Utilize spline function tocalculate the characteristic particle diameter and asymmetry coefficient of thegravel stone. Adopting Mann-Whitney U method of verify inspection , makeup statistical analysis to BAIPO material field and PUZI particle,they belongto one and the same. Established relevant relations between particle grade andporosity.According to the information of the osmosis test, have established arelation between the seepage coefficient and the control granule diameter, andthe gravel percent, and the function of hole percent. Adopting the K-S methodto verify single swatch, inferred the logarithm of seepage coefficient obeyingnormal distribution. The method of utilizing multinomials to fit , has got theprobability density of permeates coefficient.According to the information of permeating distortion test, haveresearched the critical hydraulic grads. Further , have produced the allowablehydraulic grads, regarded as standard to judge that osmosis destroy the dam ornot.grounding on the basic theories seepage and the structure ofXIXIAYUAN earth dam ,the geologic condition, adopting the seepageanalytical method of continuous medium, set up the models for analyzingseepage of the dam. Utilizing the finite element principle to calculate theseepage , has received the influent characteristic under many kinds ofoperating modes, According to the analysis result under the state of differentprevention of seepage , have recommended the scheme of rational preventionof seepage.Being based upon influent analysis , have proposed two suggestions inthe prevention of seepage. First,, according to the different results ofcalculation, propose setting up filtrating layer at the backward lower reachesof the dam , taking the effective protective measure to the dam body. Second,according to the influent characteristic of the dam body at the time of partdamage of got-up geotechnological membrane, propose taking the protectivemeasure in the course of transporting and laying the got-up geotechnologicalmembrane, to prevent got-up geotechnological membrane damage from andincrease its permeability;When the got-up geotechnological membrane iswelded or the sticky seam , should control quality.更多还原