在长江中下游历史险情资料调研的基础上,提出了一种盲沟管与传统人字沟相结合的新型导渗结构,并开展了不同水力梯度下不同土工织物长期淤堵试验和新型导渗结构排水物理模型试验.结果表明:改进后的盲沟管具有良好的反滤排水特性和抗淤堵特性,可为汛期散浸险情抢险提供参考.

闸站基坑开挖过程中的降水问题重要且复杂.采用"大井法"和数值模拟2种方法,对引江济淮工程中凤凰颈泵站改造的基坑涌水量进行了计算.基于三维渗流模型对基坑降水方案作了优化研究,对比分析了降水井的空间布置和井深度变化对基坑降水效果的影响,并综合考虑了工程经济性和施工便捷性,最终得到了推荐的降水方案.通过对各降水方案的分析可知:在基坑降水满足降深要求的前提下,降水井空间分布越均匀,各井抽水量的差距越小,有利于统一的水泵配购;将降水井布置在基坑周边,避免在基坑内部布井,能够减小对施工的干扰,但会显著提高总抽水量;降水井深度越大,需要布置的降水井数目越少,基坑总抽水量越大.该研究为闸站基坑降水方案的优化提供了良好的思路和范例.

The concepts of piping’s criticality and piping tending to breach dyke were presented in the light of some cases of piping happened in the Jingjiang stretch of Yangtze River dyke and the studies of piping modelling. The concept of piping’s criticality is conducive for the quantitative research on factors affecting piping’s evolution. Spe-cial influence factors on criticality of piping include: flood process, water level in the protected area, piping’s lo-cation, structure and soil properties near the piping and along its evolution path, as well as seepage control meas-ures. Classifying piping according to criticality lays an important foundation for the separate treatment of different piping types,and is also a vital approach to improving the pertinence and scientific decision of piping treatment. Generally, piping in the embankment, and those extending fast to the embankment, should be recognized as piping tending to breach dyke, which should be followed with treatment measures to hinder the evolution, or emergency plans implemented immediately.

Cushion layer is an important subarea of concrete faced rockfill dam (CFRD).Prior to the construction of CFRD for Shitouxia Hydropower Station in Qinghai,China,sandy gravel materials collected from riverbed were checked,and the results revealed that the weight percentage of fine grains in the samples screened under mesh size of 100 mm(directly screened cushion material) was likely inferior to the low limit required for cushion layer.Seepage destruction and filter tests were performed for the directly screened materials and transition zone materials.Seepage field in the dam and probable maximum hydraulic gradient values both in cushion and transition zones were forecasted by numerical simulation method.The applicability of tested samples were assessed on the basis of seepage characteristics for cushion zone materials in response to the functional requirements of water leakage and seepage destruction control.The directly screened materials were judged unsuitable for cushion layer.Moreover,a scheme was proposed to improve the filling material by adding fine grains screened under mesh size of 5 mm to the directly screened material.The improved materials were checked with seepage destruction and filter tests,and were demonstrated applicable for dam cushion layer.The dam has been built up and has performed well during reservoir impoundment even under earthquake.This example tells the necessity of research on filling material throughout the construction of any embankment dam.Proof tests and applicability assessment should be taken for the natural or produced materials as early as possible before the dam fill construction.

由于膨胀土对于水的敏感性,膨胀土渠坡及其衬砌结构的稳定性是南水北调中线一期工程建设和运行遇到的重要挑战之一.在地层结构分类基础上,开展了膨胀土地区的渗透结构分类、渗流系统分类以及膨胀土渠坡渗流系统分类研究.针对各类膨胀土渠坡渗流系统,分析了渠道工程对渗流场的改造作用,归纳了各自的渗流控制任务,提出了渗流控制措施的应用原则:非饱和带设置排水垫层以利于含水率的长效控制,合理设计马道以减轻对渗流控制的负效应,合理运用排水孔和减压井控制地下水流场及水压力,地下水动态变化与渠道水位变化范围交叉渠段应合理设置逆止阀并保障其灵敏性和可靠性,工程长期运行过程中跟踪研究渗流控制效果和适时有效调控渗流场.

A transient saturate-unsaturated water flow model is adopted to simulate the seepage field in Shuibuya Concrete Faced Rockfill Dam under different conditions: concrete face functions normally,cracks locally or does not work totally.The distribution of water head and hydraulic gradient in different dam zone is analyzed.The max hydraulic gradient that might appear in the padding zone,transition zone and main rockfill zone is suggested separately, which would control the seepage stability status of the dam.Hereby,the design standard for acceptable seepage gradient of rockfill materials is suggested.This standard can be used to estimate the rationality of hydraulic transition and seepage stability for the dam..