山区河流散抛石坝防冲毁措施研究

【作者】 瞿凌锋；

【导师】 张玮；

【作者基本信息】 河海大学 ， 港口海岸及近海工程， 2003， 硕士

【摘要】 山区河流坡降大、流速急且分布不均，散抛石坝水毁现象较为普遍，开展相关问题研究十分必要。本文首先根据散抛石坝损毁情况的现场调查资料，结合有关专家多年的整治经验，总结出坝体的损毁原因及影响因素；对现有块体稳定性的研究成果进行回顾和总结，并针对散抛石坝的直接损毁现象，结合山区河流的水流、地形特点，利用块体粒径与起动流速的关系，提出块体稳定重量与起动流速高次方成正比的概念，流速50％的增长可能导致块体稳定重量接近40倍的变化；通过二维变坡水槽试验，研究了坝体稳定的主要影响因素，包括块体重量、坝顶水深、断面尺寸、块体材料(块石和卵石两种)、护底等，结果表明对于山区河流，试图仅仅通过增加坝体单个块体重量或断面尺寸来提高坝体稳定性效果甚微；最后，根据西部地区的自然、经济、交通等条件，提出可以采用柔性混凝土铰链体等一类整体性较好的护面层作为散抛石坝的防冲毁措施，以期取得良好的工程效果。更多还原

【Abstract】 Loose rock dams are often destroyed due to rapid flow velocity in mountain streams. In this thesis, first, reasons and factors for the stability of loose rock dams were summarized according to the field surveys and certain expert’s experiences. Then, researches on block stability problems were reviewed, and according to the relationship between grain size and incipient velocity, it is found that the block weight is in direct proportion to 6-9 power of incipient velocity, and 50% increase of the velocity willresult in about 40 times change of the block weight. After that, experiments were conducted in a flume, focusing on the relationship between incipient velocity and some main factors including block weight, water depth over the dam, cross-section size, block material and river bed material. The result shows that it is not appropriate to improve the stability of loose rock dams by simply increasing the block weight. Finally, a flexile concrete gemel was suggested to protect loose rock dams.更多还原