中文摘要：

透水四面体框架群能降低其附近的水流流速、耗散水流的能量,起到减速防冲和促淤的效果,同时也可以保护床沙、抑制局部冲刷。不同的抛投密度防护效果也不同,随着抛投密度的增加,其防护效果几乎线性增强,但达到一定限度后将不再增加。抛石防护是使用历史较早、使用频率较高的一种桥墩局部冲刷防护措施。抛石防护就是将所选石料布设于桥墩周围床面上,用以提高桥墩周围河床床面的抗冲能力。抛石防护主要工作原理是保护床沙、增加其起动或扬动流速;增大桥墩附近局部糙率、减小局部流速。本文采用多组水槽清水冲刷试验,对比分析了透水四面体框架群在不同抛投密度条件下的防护效果差异,及其与抛石防护桥墩局部冲刷的最大深度及其整体防护效果的优劣,为四面体框架群和抛石防护的应用提供一些决策所必须的技术参数。

英文摘要：

Many countermeasures for local scour protection are developed for keeping river-bed from scouring around bridge piers,such as ripraps/and tetrahedron frame group.Countermeasures are divided into two types： to enhance the ability of the bed material to resist scour and to reduce the power of eroding agents.The riprap is usually used as the former type of countermeasure.The tetrahedron frame group has both of the two functions to resist bed scour around piers and is considered as a new approach to provide protection to piers.In this study,a series of experimental tests are conducted in a flume and protective effects of local scour around a pier using riprap or tetrahedron frame group with different densities of layout are discussed,which provide information for scour protection design around pies.