Research on hydraulic and mechanical design of flowthrough rockfill dams.

本研究的目的是为干旱、半干旱地区的防洪或水资源开发而修建的“过流式堆石坝”制定一种水力设计方案。在研究的第一年，通过堆石体的水头损失特性进行了调查和建模。在第二年的研究中，对堆石结构的渗流特性进行了研究，并提出了一些实用的设计方案。主要研究成果如下：1）通过室内一维渗透试验，研究了堆石体中水力坡降与流速的关系。采用Forchheimer方程较好地模拟了堆石体中水流的水头损失特性。成功地将水力平均孔隙半径引入到水头损失方程中，以描述岩石颗粒形状、孔隙尺寸和几何形状对通过堆石体的水流的影响。2）有限元数值 ...更多信息 摘要开发了计算堆石结构水流水头损失特性的程序。通过与室内水槽试验结果的对比，验证了本文提出的水头损失方程的适用性以及所开发的有限元数值程序的有效性。3）将本文提出的水头损失方程应用于确定小、大尺寸过流堆石坝的水位流量关系曲线。结果表明，堆石体过流流量随上游水位的增加呈指数增长，温度变化对水位流量关系曲线无明显影响。4）采用有效水力坡降概念，建立了统一的水位流量关系曲线，可方便、简便地估算堆石体过流流量。结果表明，采用一种简单实用的设计方案来确定堆石结构的水力特性是可行的。少

The purpose of the RESEARCH is to develop a hydraulic design scheme of "flowthrough rockfill dams" which have been constructed for flood control or water resource development in arid and semi-arid region. In the first year of the RESEARCH the head loss property of flow through rockfill was investigated and modeled. In the second year of the RESEARCH the flow transmissibility of the rockfill structures was investigated and some practical design scheme was proposed. The research results are summarized as follows :1) The laboratory one-dimensional permeability tests were conducted to measure the relationship between the hydraulic gradient and the velocity of flow through rockfill column. The head loss property of flow through rockfill was well modeled by using the Forchheimer equation. The hydraulic mean radius of voids was successfully introduced into the head loss equation to describe the effects of rock particle shape, void size and geometry on the flow through rockfill.2) The FEM nume … More rical code was developed to estimate the head loss property of flow through rockfill structures. By comparing the FEM estimation with the laboratory water flume tests the applicability of the head loss equation proposed above as well as the validity of the FEM numerical code developed were examined.3) The FEM numerical code incorporating the head loss equation proposed was applied to determine the stage-discharge rating curve of small to large size flowthrough rockfill dams. It was shown that the flow discharge through rockfill structure increases exponentially with the upstream water level, and that no effect of flow temperature on the stage-discharge rating curve can be seen.4) A unified stage-discharge rating curve was determined by employing the concept of effective hydraulic gradient, from which the flow discharge through rockfill structures can be easily and simply estimated. It was concluded that a simple and practical design scheme to determine the hydraulic properties of rockfill structures nay be feasible. Less